Sample records for ra zr hf

  1. Ternary ceramic alloys of Zr-Ce-Hf oxides

    DOE Patents [OSTI]

    Becher, P.F.; Funkenbusch, E.F.

    1990-11-20T23:59:59.000Z

    A ternary ceramic alloy is described which produces toughening of zirconia and zirconia composites through the stress transformation from tetragonal phase to monoclinic phase. This alloy, having the general formula Ce[sub x]Hf[sub y]Zr[sub 1[minus]x[minus]y]O[sub 2], is produced through the addition of appropriate amounts of ceria and hafnia to the zirconia. Typically, improved toughness is achieved with about 5 to about 15 mol % ceria and up to about 40 mol % hafnia. The preparation of alloys of these compositions are given together with data as to the densities, tetragonal phase content, hardness and fracture toughness. The alloys are useful in preparing zirconia bodies as well as reinforcing ceramic composites. 1 fig.

  2. ACCEPTED MANUSCRIPT The behaviour of Rare-Earth Elements, Zr and Hf during biologically-mediated

    E-Print Network [OSTI]

    ACCEPTED MANUSCRIPT ACCEPTED MANUSCRIPT 1 The behaviour of Rare-Earth Elements, Zr and Hf during.a,b* , Cangemi M.a , Brusca L.c , Madonia P.c , Saiano F.d , Zuddas P.e a) Department of Earth and Marine at the solid-liquid interface influencing the distribution of trace elements onto microbial surfaces. Since

  3. Ternary ceramic alloys of ZR-CE-HF oxides

    DOE Patents [OSTI]

    Becher, Paul F. (Oak Ridge, TN); Funkenbusch, Eric F. (White Bear Lake, MN)

    1990-01-01T23:59:59.000Z

    A ternary ceramic alloy which produces toughening of zirconia and zirconia composites through the stress transformation from tetragonal phase to monoclinic phase. This alloy, having the general formula Ce.sub.x Hf.sub.y Zn.sub.1-x-y O.sub.2, is produced through the addition of appropriate amounts of ceria and hafnia to the zirconia. Typically, improved toughness is achieved with about 5 to about 15 mol % ceria and up to about 40 mol % hafnia. The preparation of alloys of these compositions are given together with data as to the densities, tetragonal phase content, hardness and fracture toughness. The alloys are useful in preparing zirconia bodies as well as reinforcing ceramic composites.

  4. First-principles phase diagram calculations for the HfCTiC, ZrCTiC, and HfCZrC solid O. Adjaoud,1,*,

    E-Print Network [OSTI]

    Steinle-Neumann, Gerd

    Transition metal carbides, including the NaCl-structured group IV Ti, Zr, and Hf carbides, have extremely of oxidizing agents, and retain good corrosion resistance to high temperature.1,5,6 The transition-metal high melting points and are therefore referred to collectively as the "refractory carbides

  5. A new class of materials with promising thermoelectric properties: MNiSn (M=Ti, Zr, Hf)

    SciTech Connect (OSTI)

    Hohl, H.; Ramirez, A.P.; Kaefer, W.; Fess, K.; Thurner, Ch.; Kloc, Ch.; Bucher, E.

    1997-07-01T23:59:59.000Z

    TiNiSn, ZrNiSn and HfNiSn are members of a large group of intermetallic compounds which crystallize in the cubic MgAgAs-type structure. Polycrystalline samples of these compounds have been prepared and investigated for their thermoelectric properties. With thermopowers of about {minus}200 {micro}V/K and resistivities of a few m{Omega}cm, power factors S{sup 2}/{rho} as high as 38 {micro}W/K{sup 2}cm were obtained at 700 K. These remarkably high power factors are, however, accompanied by a thermal conductivity, solid solutions Zr{sub 1{minus}x}Hf{sub x}NiSn, Zr{sub 1{minus}x}Ti{sub x}NiSn, and Hf{prime}{sub 1{minus}x}Ti{sub x}NiSn were formed. The figure of merit of Zr{sub 0.5}Hf{sub 0.5}NiSn at 700 K (ZT = 0.41) exceeds the end members ZrNiSn (ZT = 0.26) and HfNiSn (ZT = 0.22).

  6. 13.21 Geochemistry of the Rare-Earth Element, Nb, Ta, Hf, and Zr Deposits RL Linnen, University of Western Ontario, London, ON, Canada

    E-Print Network [OSTI]

    Chakhmouradian, Anton

    13.21 Geochemistry of the Rare-Earth Element, Nb, Ta, Hf, and Zr Deposits RL Linnen, University to Y, the rare- earth elements (REE, La to Lu), Zr, Hf, Nb, and Ta. The rare elements, Canada ã 2014 Elsevier Ltd. All rights reserved. 13.21.1 Introduction 543 13.21.1.1 Uses of Rare Elements

  7. Electric transport properties of the pentatelluride materials HfTe{sub 5} and ZrTe{sub 5}

    SciTech Connect (OSTI)

    Tritt, T.M.; Wilson, M.L.; Littleton, R.L. [and others

    1997-07-01T23:59:59.000Z

    The authors have measured the resistivity and thermopower of single crystals as well as polycrystalline pressed powders of the low-dimensional pentatelluride materials: HfTe{sub 5} and ZrTe{sub 5}. They have performed these measurements as a function of temperature between 5K and 320K. In the single crystals there is a peak in the resistivity for both materials at a peak temperature, T{sub p} where T{sub p} {approx} 80K for HfTe{sub 5} and T{sub p} {approx} 145K for ZrTe{sub 5}. Both materials exhibit a large p-type thermopower around room temperature which undergoes a change to n-type below the peak. These data are similar to behavior observed previously in these materials. They have also synthesized pressed powders of polycrystalline pentatelluride materials, HfTe{sub 5} and ZrTe{sub 5}. They have measured the resistivity and thermopower of these polycrystalline materials as a function of temperature between 5K and 320K. For the polycrystalline material, the room temperature thermopower for each of these materials is relatively high, +95 {micro}V/K and +65 {micro}V/K for HfTe{sub 5} and ZrTe{sub 5}, respectively. These values compare closely to thermopower values for single crystals of these materials. At 77 K, the thermopower is +55 {micro}V/K for HfTe{sub 5} and +35 {micro}V/K for ZrTe{sub 5}. In fact, the thermopower for the polycrystals decreases monotonically with temperature to T {approx} 5K, thus exhibiting p-type behavior over the entire range of temperature. As expected, the resistivity for the polycrystals is higher than the single crystal material, with values of 430 m{Omega}-cm and 24 m{Omega}-cm for HfTe{sub 5} and ZrTe{sub 5} respectively, compared to single crystal values of 0.35 m{Omega}-cm (HfTe{sub 5}) and 1.0 m{Omega}-cm (ZrTe{sub 5}). The authors have found that the peak in the resistivity evident in both single crystal materials is absent in these polycrystalline materials. They will discuss these materials in relation to their potential as candidates for thermoelectric applications.

  8. Memory functions of nanocrystalline cadmium selenide embedded ZrHfO high-k dielectric stack

    SciTech Connect (OSTI)

    Lin, Chi-Chou; Kuo, Yue [Thin Film Nano and Microelectronics Research Laboratory, Artie McFerrin Department of Chemical Engineering, Texas A and M University, College Station, Texas 77843-3122 (United States)

    2014-02-28T23:59:59.000Z

    Metal-oxide-semiconductor capacitors made of the nanocrystalline cadmium selenide nc-CdSe embedded Zr-doped HfO{sub 2} high-k stack on the p-type silicon wafer have been fabricated and studied for their charge trapping, detrapping, and retention characteristics. Both holes and electrons can be trapped to the nanocrystal-embedded dielectric stack depending on the polarity of the applied gate voltage. With the same magnitude of applied gate voltage, the sample can trap more holes than electrons. A small amount of holes are loosely trapped at the nc-CdSe/high-k interface and the remaining holes are strongly trapped to the bulk nanocrystalline CdSe site. Charges trapped to the nanocrystals caused the Coulomb blockade effect in the leakage current vs. voltage curve, which is not observed in the control sample. The addition of the nanocrystals to the dielectric film changed the defect density and the physical thickness, which are reflected on the leakage current and the breakdown voltage. More than half of the originally trapped holes can be retained in the embedded nanocrystals for more than 10 yr. The nanocrystalline CdSe embedded high-k stack is a useful gate dielectric for this nonvolatile memory device.

  9. Microstructural Characterization and Shape Memory Response of Ni-Rich NiTiHf and NiTiZr High Temperature Shape Memory Alloys

    E-Print Network [OSTI]

    Evirgen, Alper

    2014-08-14T23:59:59.000Z

    NiTiHf and NiTiZr high temperature shape memory alloys (HTSMAs) have drawn a great deal of attention as cheaper alternatives to Pt, Pd and Au alloyed NiTi-based HTSMAs while NiTiZr alloys also providing at least 20% weight reduction then its Ni...

  10. Two-Dimensional Polaronic Behavior in the Binary Oxides m-HfO2 and m-ZrO2

    SciTech Connect (OSTI)

    McKenna, K. P.; Wolf, M. J.; Shluger, A. L.; Lany, S.; Zunger, A.

    2012-03-16T23:59:59.000Z

    We demonstrate that the three-dimensional (3D) binary monoclinic oxides HfO{sub 2} and ZrO{sub 2} exhibit quasi-2D polaron localization and conductivity, which results from a small difference in the coordination of two oxygen sublattices in these materials. The transition between a 2D large polaron into a zero-dimensional small polaron state requires overcoming a small energetic barrier. These results demonstrate how a small asymmetry in the lattice structure can determine the qualitative character of polaron localization and significantly broaden the realm of quasi-2D polaron systems.

  11. Electron-stimulated desorption from polished and vacuum fired 316LN stainless steel coated with Ti-Zr-Hf-V

    SciTech Connect (OSTI)

    Malyshev, Oleg B., E-mail: oleg.malyshev@stfc.ac.uk; Valizadeh, Reza; Hogan, Benjamin T.; Hannah, Adrian N. [ASTeC, STFC Daresbury Laboratory, Daresbury, Warrington, WA4 4AD Cheshire (United Kingdom)

    2014-11-01T23:59:59.000Z

    In this study, two identical 316LN stainless steel tubular samples, which had previously been polished and vacuum-fired and then used for the electron-stimulated desorption (ESD) experiments, were coated with Ti-Zr-Hf-V with different morphologies: columnar and dense. ESD measurement results after nonevaporable getter (NEG) activation to 150, 180, 250, and 350?°C indicated that the values for the ESD yields are significantly (2–20 times) lower than the data from our previous study with similar coatings on nonvacuum-fired samples. Based on these results, the lowest pressure and best long-term performance in particle accelerators will be achieved with a vacuum-fired vacuum chamber coated with dense Ti-Zr-Hf-V coating activated at 180?°C. This is likely due to the following facts: after NEG activation, the hydrogen concentration inside the NEG was lower than in the bulk stainless steel substrate; the NEG coating created a barrier for gas diffusion from the sample bulk to vacuum; the dense NEG coating performed better as a barrier than the columnar NEG coating.

  12. First principle study of elastic and thermodynamic properties of ZrZn{sub 2} and HfZn{sub 2} under high pressure

    SciTech Connect (OSTI)

    Sun, Na; Zhang, Xinyu, E-mail: jiaqianqin@gmail.com; Ning, Jinliang; Zhang, Suhong; Liang, Shunxing; Ma, Mingzhen; Liu, Riping [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China); Qin, Jiaqian, E-mail: jiaqianqin@gmail.com [Metallurgy and Materials Science Research Institute, Chulalongkorn University, Bangkok 10330 (Thailand)

    2014-02-28T23:59:59.000Z

    A comprehensive investigation of the structural, elastic, and thermodynamic properties for Laves-phases ZrZn{sub 2} and HfZn{sub 2} are conducted using density functional total energy calculations combined with the quasi-harmonic Debye model. The optimized lattice parameters of ZrZn{sub 2} and HfZn{sub 2} compare well with available experimental values. We estimated the mechanical behaviors of both compounds under compression, including mechanical stability, Young's modulus, Poisson's ratio, ductility, and anisotropy. Additionally, the thermodynamic properties as a function of pressure and temperature are analyzed and found to be in good agreement with the corresponding experimental data.

  13. Thermal stability of Al- and Zr-doped HfO{sub 2} thin films grown by direct current magnetron sputtering

    SciTech Connect (OSTI)

    Hong, Yeong-Eui; Kim, Yong-Seok; Do, Kihoon; Lee, Dongwon; Ko, Dae-Hong; Ku, Ja-Hum; Kim, Hyoungsub [Department of Ceramic Engineering, Yonsei University, 134 Shinchon-Dong, Seodaemoon-Ku, Seoul 120-749 (Korea, Republic of); Semiconductor R and D Division, Samsung Electronics Co, Ltd., San no. 24, Nongseo-Ri, Kiheung-Eup, Yongin-City, Kyunggi-Do 449-711 (Korea, Republic of); Department of Advanced Materials Engineering, Sungkyunkwan University, 300 Chunchun-Dong, Jangan-Ku, Suwon 440-746 (Korea, Republic of)

    2005-09-15T23:59:59.000Z

    Ultrathin HfO{sub 2} dielectric films doped with Al and Zr were grown on p-type Si(100) substrates by dc magnetron sputtering, and their microstructural and electrical properties were examined. Compositions and chemical states of the dielectric films were analyzed by Rutherford backscattering spectrometry and x-ray photoelectron spectroscopy. The HfO{sub 2} films doped with Zr were crystallized even from the as-deposited state, however, the crystallization temperature of the HfO{sub 2} film doped with 16% Al{sub 2}O{sub 3} was delayed up to 900 deg. C. As the annealing temperature increases, high-resolution transmission electron microscopy analyses of all doped HfO{sub 2} films showed an increase of the interfacial layer thickness due to the diffusion of small partial pressure of oxygen in annealing ambient. Our results also showed that the addition of Al{sub 2}O{sub 3} to 14% is not useful for blocking the oxygen diffusion through the (HfO{sub 2}){sub 0.86}(Al{sub 2}O{sub 3}){sub 0.14} film. From the capacitance-voltage measurements, the dielectric constants of the Al- and Zr-doped HfO{sub 2} thin films were measured to be 18.7 and 7.6, respectively.

  14. Thermal and electronic charge transport in bulk nanostructured Zr{sub 0.25}Hf{sub 0.75}NiSn composites with full-Heusler inclusions

    SciTech Connect (OSTI)

    Makongo, Julien P.A.; Misra, Dinesh K. [Advanced Materials Research Institute, University of New Orleans, New Orleans, LA 70148 (United States); Salvador, James R. [Chemical Sciences and Materials Systems Laboratory, General Motors R and D Center, Warren, MI 48090 (United States); Takas, Nathan J. [Advanced Materials Research Institute, University of New Orleans, New Orleans, LA 70148 (United States); Wang, Guoyu [Department of Physics, University of Michigan, Ann Arbor, MI 48109 (United States); Shabetai, Michael R.; Pant, Aditya; Paudel, Pravin [Advanced Materials Research Institute, University of New Orleans, New Orleans, LA 70148 (United States); Uher, Ctirad [Department of Physics, University of Michigan, Ann Arbor, MI 48109 (United States); Stokes, Kevin L. [Advanced Materials Research Institute, University of New Orleans, New Orleans, LA 70148 (United States); Department of Physics, University of New Orleans, New Orleans, LA 70148 (United States); Poudeu, Pierre F.P., E-mail: ppoudeup@umich.edu [Advanced Materials Research Institute, University of New Orleans, New Orleans, LA 70148 (United States); Department of Chemistry, University of New Orleans, New Orleans, LA 70148 (United States); Laboratory for Emerging Energy and Electronic Materials, Materials Science and Engineering Department, University of Michigan, Ann Arbor, MI 48109 (United States)

    2011-11-15T23:59:59.000Z

    Bulk Zr{sub 0.25}Hf{sub 075}NiSn half-Heusler (HH) nanocomposites containing various mole fractions of full-Heusler (FH) inclusions were prepared by solid state reaction of pre-synthesized HH alloy with elemental Ni at 1073 K. The microstructures of spark plasma sintered specimens of the HH/FH nanocomposites were investigated using transmission electron microscopy and their thermoelectric properties were measured from 300 K to 775 K. The formation of coherent FH inclusions into the HH matrix arises from solid-state Ni diffusion into vacant sites of the HH structure. HH(1-y)/FH(y) composites with mole fraction of FH inclusions below the percolation threshold, y{approx}0.2, show increased electrical conductivity, reduced Seebeck coefficient and increased total thermal conductivity arising from gradual increase in the carrier concentration for composites. A drastic reduction ({approx}55%) in {kappa}{sub l} was observed for the composite with y=0.6 and is attributed to enhanced phonon scattering due to mass fluctuations between FH and HH, and high density of HH/FH interfaces. - Graphical abstract: Large reduction in the lattice thermal conductivity of bulk nanostructured half-Heusler/full-Heusler (Zr{sub 0.25}Hf{sub 075}NiSn/ Zr{sub 0.25}Hf{sub 075}Ni{sub 2}Sn) composites, obtained by solid-state diffusion at 1073 K of elemental Ni into vacant sites of the half-Heusler structure, arising from the formation of regions of spinodally decomposed HH and FH phases with a spatial composition modulation of {approx}2 nm. Highlights: > Bulk composites from solid state transformation of half-Heusler matrix through Ni diffusion. > Formation of coherent phase boundaries between half-Heusler matrix and full-Heusler inclusion. > Alteration of thermal and electronic transports with increasing full-Heusler inclusion. > Enhanced phonon scattering at half-Heusler/ full-Heusler phase boundaries.

  15. Exploration of R2XM2 (R=Sc, Y, Ti, Zr, Hf, rare earth; X=main group element; M=transition metal, Si, Ge): Structural Motifs, the novel Compound Gd2AlGe2 and Analysis of the U3Si2 and Zr3Al2 Structure Types

    SciTech Connect (OSTI)

    Sean William McWhorter

    2006-05-01T23:59:59.000Z

    In the process of exploring and understanding the influence of crystal structure on the system of compounds with the composition Gd{sub 5}(Si{sub x}Ge{sub 1-x}){sub 4} several new compounds were synthesized with different crystal structures, but similar structural features. In Gd{sub 5}(Si{sub x}Ge{sub 1-x}){sub 4}, the main feature of interest is the magnetocaloric effect (MCE), which allows the material to be useful in magnetic refrigeration applications. The MCE is based on the magnetic interactions of the Gd atoms in the crystal structure, which varies with x (the amount of Si in the compound). The crystal structure of Gd{sub 5}(Si{sub x}Ge{sub 1-x}){sub 4} can be thought of as being formed from two 3{sup 2}434 nets of Gd atoms, with additional Gd atoms in the cubic voids and Si/Ge atoms in the trigonal prismatic voids. Attempts were made to substitute nonmagnetic atoms for magnetic Gd using In, Mg and Al. Gd{sub 2}MgGe{sub 2} and Gd{sub 2}InGe{sub 2} both possess the same 3{sup 2}434 nets of Gd atoms as Gd{sub 5}(Si{sub x}Ge{sub 1-x}){sub 4}, but these nets are connected differently, forming the Mo{sub 2}FeB{sub 2} crystal structure. A search of the literature revealed that compounds with the composition R{sub 2}XM{sub 2} (R=Sc, Y, Ti, Zr, Hf, rare earth; X=main group element; M=transition metal, Si, Ge) crystallize in one of four crystal structures: the Mo{sub 2}FeB{sub 2}, Zr{sub 3}Al{sub 2}, Mn{sub 2}AlB{sub 2} and W{sub 2}CoB{sub 2} crystal structures. These crystal structures are described, and the relationships between them are highlighted. Gd{sub 2}AlGe{sub 2} forms an entirely new crystal structure, and the details of its synthesis and characterization are given. Electronic structure calculations are performed to understand the nature of bonding in this compound and how electrons can be accounted for. A series of electronic structure calculations were performed on models with the U{sub 3}Si{sub 2} and Zr{sub 3}Al{sub 2} structures, using Zr and A1 as the building blocks. The starting point for these models was the U{sub 3}Si{sub 2} structure, and models were created to simulate the transition from the idealized U{sub 3}Si{sub 2} structure to the distorted Zr{sub 3}Al{sub 2} structure. Analysis of the band structures of the models has shown that the transition from the U{sub 3}Si{sub 2} structure to the Zr{sub 3}Al{sub 2} structure lifts degeneracies along the {Lambda} {yields} Z direction, indicating a Peierls-type mechanism for the displacement occurring in the positions of the Zr atoms.

  16. WUSM RA Forum Grants & Contracts

    E-Print Network [OSTI]

    Kroll, Kristen L.

    1 WUSM RA Forum March 2006 Grants & Contracts #12;2 NIH Update #12;3 Beginning February 1, 2006, National Institute of Health (NIH) will stop sending summary statements and Peer Review Outcome letter NIH eRA Commons #12;4 Advantages to Registering in the NIH eRA Commons: · The NIH eRA Commons

  17. Co.ra

    Office of Legacy Management (LM)

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  18. Hf-irJ

    Office of Legacy Management (LM)

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  19. RA

    National Nuclear Security Administration (NNSA)

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  20. Phase selection and transition in Hf-rich hafnia-titania nanolaminates

    SciTech Connect (OSTI)

    Cisneros-Morales, Massiel Cristina; Rubin Aita, Carolyn

    2011-06-15T23:59:59.000Z

    Hf-rich hafnia-titania nanolaminate films with five HfO{sub 2}-TiO{sub 2} bilayer architectures (0.64 to 0.94 Hf atom fraction) were sputter deposited on unheated fused silica substrates, annealed post-deposition from 573 to 1273 K, and analyzed by x-ray diffraction to study phase selection and transition. Isochronal annealing for 1 h intervals from 573 to 1173 K produces weak crystallization into monoclinic (m) HfO{sub 2} doped with Ti, i.e., m-Hf{sub 1-x}Ti{sub x}O{sub 2}. The amount of Ti incorporated into m-HfO{sub 2} depends upon both architecture and overall stoichiometry, but in all but the coarsest architecture, exceeds the bulk solubility limit of x = 0.05. Initial annealing at 1273 K produces significant crystallization into a biphasic structure, m-Hf{sub 1-x}Ti{sub x}O{sub 2} and orthorhombic (o) HfTiO{sub 4}. From bulk phase equilibrium considerations, o-HfTiO{sub 4} is expected to crystallize under conditions of interfacial bilayer mixing. However, upon further annealing at 1273 K, o-HfTiO{sub 4} proves to be unstable. o-HfTiO{sub 4} demixing inevitably occurs independent of architecture and stoichiometry, resulting in final crystallization products after 96 h at 1273 K that are m-Hf{sub 1-x}Ti{sub x}O{sub 2} with x {approx_equal} 0.05 and TiO{sub 2} doped with Hf. We suggest that o-HfTiO{sub 4} instability arises from a driving force to form domains similar to those found in the low temperature in/commensurate structures of ZrTiO{sub 4}. A detailed crystallographic group-subgroup analysis of the o (Pbcn) {yields} m (P2{sub 1}/c) transition shows that these domains can be represented by an orientation twin in the latter structure and their creation can be achieved by a single step second-order phase transition.

  1. Characterization of Ceramic Plasma-Sprayed Coatings, and Interaction Studies Between U-Zr Fuel and Ceramic Coated Interface at an Elevated Temperature

    SciTech Connect (OSTI)

    Ki Hwan Kim; Chong Tak Lee; R. S. Fielding; J. R. Kennedy

    2011-08-01T23:59:59.000Z

    Candidate coating materials for re-usable metallic nuclear fuel crucibles, HfN, TiC, ZrC, and Y2O3, were plasma-sprayed onto niobium substrates. The coating microstructure and the thermal cycling behavior were characterized, and U-Zr melt interaction studies carried out. The Y2O3 coating layer had a uniform thickness and was well consolidated with a few small pores scattered throughout. While the HfN coating was not well consolidated with a considerable amount of porosity, but showed somewhat uniform thickness. Thermal cycling tests on the HfN, TiC, ZrC, and Y2O3 coatings showed good cycling characteristics with no interconnected cracks forming even after 20 cycles. Interaction studies done on the coated samples by dipping into a U-20wt.%Zr melt indicated that HfN and Y2O3 did not form significant reaction layers between the melt and the coating while the TiC and the ZrC coatings were significantly degraded. Y2O3 exhibited the most promising performance among HfN, TiC, ZrC, and Y2O3 coatings.

  2. eRA Training Team1 Terminations

    E-Print Network [OSTI]

    Baker, Chris I.

    eRA Training Team1 xTrain Terminations Electronic Research Administration Sponsored by: The National Institutes of Health, Office of Extramural Research March 2012 #12;eRA Training Team2 xTrain General Information xTrain Overview The following section provides general information on the xTrain

  3. eRA Training Team1 Terminations

    E-Print Network [OSTI]

    Baker, Chris I.

    eRA Training Team1 xTrain Terminations Electronic Research Administration Sponsored by: The National Institutions of Health, Office of Extramural Research April 2010 #12;eRA Training Team2 xTrain General Information xTrain Overview The following section provides general information on the xTrain

  4. Magnetic properties of HITPERM ,,Fe,Co...88Zr7B4Cu1 magnets M. A. Willard,a)

    E-Print Network [OSTI]

    Laughlin, David E.

    power applications requires new bulk soft magnetic materials that 1 are capable of operating at higher magnetization that persists to the phase transformation at 980 °C. Alternating current permeability experiments nanocrystalline Fe­Si­B­Nb­Cu alloys and nanocrystalline Fe­M­B­Cu M Zr, Nb, Hf, etc. alloys have been optimized

  5. (RA) Gila's Departments (RA) Jena's Departments BK Anesthesiology LN Biomedical Engineering

    E-Print Network [OSTI]

    Mahon, Bradford Z.

    (RA) Gila's Departments (RA) Jena's Departments BK Anesthesiology LN Biomedical Engineering JC Biochemistry & Biophysics JC Biostatistics & Computational Biology BK Biomedical Genetics BK Brain & Cognitive Development & Disease AC Center for Oral Biology LN Center for Primary Care AB Center for Pediatric Biomedical

  6. Ra-226 radioassay of soil and tailings

    SciTech Connect (OSTI)

    Sabau, C.S.; Rayno, D.R.; Kretz, N.D.; Zelle, P.W.

    1983-01-01T23:59:59.000Z

    Studies of inactive uranium tailings piles have shown that tailings sands containing Ra-226 and other radionuclides may be dispersed by wind and water erosion, causing contamination of adjacent areas. To conduct an effective cleanup operation, it is necessary that boundaries of contamination be well defined. To accomplish this, data from surface gamma-ray surveys made under the Measurement Monitoring Program of the US DOE's Uranium Mill Tailings Remedial Action Project (UMTRAP) are first used to delineate a general outline of the contaminated area. Then, data from portable scintillometer surveys and from sealed-can gamma-ray analyses of soil samples are used to more precisely define the perimeter of Ra-226 contamination. These field measurements are supported by radiochemical analyses of randomly selected samples. Because of its adaptability to the widely varying chemical composition of the material in these samples, the complexing agent EDTA is used in a complexometric leaching procedure to analyze Ra-226. By this procedure, natural concentrations of Ra-226 in soil (approx. 1 pCi/g) can be measured routinely. The potential limit of detection is in the 0.1 to 0.5 pCi/g range. Details of the method, which includes leaching of radium followed by radon de-emanation, are described. Comparative data for various soil and tailings samples are presented.

  7. Metal-Organic Frameworks Based on Previously Unknown Zr8/Hf Cubic

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

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  8. Acidizing of Sandstone Reservoirs Using HF and Organic Acids

    E-Print Network [OSTI]

    Yang, Fei

    2012-10-19T23:59:59.000Z

    Mud acid, which is composed of HCl and HF, is commonly used to remove the formation damage in sandstone reservoirs. However, many problems are associated with HCl, especially at high temperatures. Formic-HF acids have served as an alternative...

  9. R.A. Spicer -Publications. January, 2010 1 R.A. Spicer Publications -Articles, Papers and Books

    E-Print Network [OSTI]

    Spicer, Robert A

    2 108. Spicer, R.A., Ahlberg, A., Herman, A.B., Hofmann, C-C., Raikevich, M., Valdes, P -de Leon, M.P., Spicer, R.A., and Steart, D.C., In Press. Climatic reconstruction of two Pliocene Yakutia). Palaeogeography, Palaeoclimatolgy, Palaeoecology, 111. Moiseeva, M.G., Herman, A.B., and Spicer

  10. Phase transformations in Cu-Zr multilayers

    SciTech Connect (OSTI)

    Weihs, T.P.; Barbee, T.W. Jr.; Wall, M.A.

    1993-04-01T23:59:59.000Z

    A study of phase transformations is reported for Cu-rich, Cu-Zr multilayer foils synthesized using magnetron sputter deposition and annealed using a differential scanning calorimeter. The foils range in composition from 1.6 to 9.0 at% Zr and consist of alternate layers of polycrystalline Cu and Zr. Differential scanning calorimetry, X-ray analysis and electron microscopy were used to three distinct reactions in the foils: a mixing and an amorphization of the Cu and die Zr, a crystallization on of this amorphous phase to the metastable intermetallic Cu{sub 5l}Zr{sub l4}, and a transformation of the Cu{sub 5l}Zr{sub l4} phase into the equilibrium phase Cu{sub 9}Zr{sub 2}. The as-deposited layering remained stable during the first two reactions and then broke down in the third reaction as large grains of Cu{sub 9}Zr{sub 2} encompassed the smaller Cu grains. Heats of the reactions and activation energies of these reactions are measured and are compared to values reported for bulk samples. The measured heats provide evidence that amorphous Cu-Zr alloys phase separate and that mixing and short range ordering produce 3.5 times more heat than long range ordering produces when Ca and Zr react and form Cu{sub 5l}Zr{sub l4}.

  11. HF separation in a carbonylation process

    SciTech Connect (OSTI)

    Grote, D.; Trivedi, B.C.; Mason, T.O.

    1987-04-28T23:59:59.000Z

    This patent describes the carbonylation of an olefin with carbon monoxide in the presence of hydrogen fluoride catalyst wherein the reaction product is treated with water to produce a mixture of a carboxylic acid, HF and optionally water. The improvement comprises contacting at a temperature in the range of from about 25/sup 0/C up to about 100/sup 0/C, the mixture with one side of a cation permeable membrane of a copolymer of tetrafluoro ethylene and perfluoro-3, 6-dioxa-4-methyl-octen sulfamic acid whose other side is in contact with water.

  12. E-Print Network 3.0 - al hf ta Sample Search Results

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    -based gate dielectric for MOSFETs with TaN metal gate. By incorporating Ta into HfO2 films, significant... shift than HfO2 3. In this work, we developed HfTaO gate ......

  13. DEPARTMENT OF CHEMICAL ENGINEERING Name of SOP Manual Hydrofluoric Acid (HF) Etching of Glass

    E-Print Network [OSTI]

    Thompson, Michael

    required Fume Hood, safety eye goggles, lab coat, two layers of nitrile gloves and HF Safety Kit Sequential containers. 5. HF is a glass etchant; only use plastic labware to contain HF. 6. Personal protective gear

  14. RAPID DETERMINATION OF RA-226 IN ENVIRONMENTAL SAMPLES

    SciTech Connect (OSTI)

    Maxwell, S.

    2012-01-03T23:59:59.000Z

    A new rapid method for the determination of {sup 226}Ra in environmental samples has been developed at the Savannah River Site Environmental Lab (Aiken, SC, USA) that can be used for emergency response or routine sample analyses. The need for rapid analyses in the event of a Radiological Dispersive Device or Improvised Nuclear Device event is well-known. In addition, the recent accident at Fukushima Nuclear Power Plant in March, 2011 reinforces the need to have rapid analyses for radionuclides in environmental samples in the event of a nuclear accident. {sup 226}Ra (T1/2 = 1,620 years) is one of the most toxic of the long-lived alpha-emitters present in the environment due to its long life and its tendency to concentrate in bones, which increases the internal radiation dose of individuals. The new method to determine {sup 226}Ra in environmental samples utilizes a rapid sodium hydroxide fusion method for solid samples, calcium carbonate precipitation to preconcentrate Ra, and rapid column separation steps to remove interferences. The column separation process uses cation exchange resin to remove large amounts of calcium, Sr Resin to remove barium and Ln Resin as a final purification step to remove {sup 225}Ac and potential interferences. The purified {sup 226}Ra sample test sources are prepared using barium sulfate microprecipitation in the presence of isopropanol for counting by alpha spectrometry. The method showed good chemical recoveries and effective removal of interferences. The determination of {sup 226}Ra in environmental samples can be performed in less than 16 h for vegetation, concrete, brick, soil, and air filter samples with excellent quality for emergency or routine analyses. The sample preparation work takes less than 6 h. {sup 225}Ra (T1/2 = 14.9 day) tracer is used and the {sup 225}Ra progeny {sup 217}At is used to determine chemical yield via alpha spectrometry. The rapid fusion technique is a rugged sample digestion method that ensures that any refractory radium particles are effectively digested. The preconcentration and column separation steps can also be applied to aqueous samples with good results.

  15. Hf propagation through actively modified ionospheres

    SciTech Connect (OSTI)

    Argo, P.E.; Fitzgerald, T.J.; Wolcott, J.H.; Simons, D.J. (Los Alamos National Lab., NM (USA)); Warshaw, S.; Carlson, R. (Lawrence Livermore National Lab., CA (USA))

    1990-01-01T23:59:59.000Z

    We have developed a computer modeling capability to predict the effect of localized electron density perturbations created by chemical releases or high-power radio frequency heating upon oblique, one-hop hf propagation paths. We have included 3-d deterministic descriptions of the depleted or enhanced ionization, including formation, evolution, and drift. We have developed a homing ray trace code to calculate the path of energy propagation through the modified ionosphere in order to predict multipath effects. We also consider the effect of random index of refraction variations using a formalism to calculate the mutual coherence functions for spatial and frequency separations based upon a path integral solution of the parabolic wave equation for a single refracted path through an ionosphere which contains random electron density fluctuations. 5 refs., 8 figs.

  16. Simulation of Heat Treatment Distortion R.A. Hardin1

    E-Print Network [OSTI]

    Beckermann, Christoph

    quenched in water and in oil. Unfortunately, due to the lack of documentation on the heat treatment processSimulation of Heat Treatment Distortion R.A. Hardin1 and C. Beckermann2 1 Research Engineer, 2 Abstract This paper gives an overview of the problem of heat treatment stress and distortion and a review

  17. NEWS & VIEWS X-RaY oPtiCS

    E-Print Network [OSTI]

    Loss, Daniel

    NEWS & VIEWS X-RaY oPtiCS Clarity through a keyhole Janos Hajdu1,2 & Filipe R. n. C. maia2 are at 1 Stanford Synchrotron Radiation Laboratory, Stanford Linear Accelerator Center, 2575 Sand Hill Road, Menlo, as it does in conventional crystallography, but only on the wavelength used, the extent of ionization damage

  18. Audit Report: OAS-RA-L-13-01 | Department of Energy

    Energy Savers [EERE]

    RA-L-13-01 Audit Report: OAS-RA-L-13-01 November 1, 2012 Implementation of the Department of Energy's Concentrating Solar Power Program The Department of Energy's (Department)...

  19. Amorphous powders of Al-Hf prepared by mechanical alloying

    SciTech Connect (OSTI)

    Schwarz, R.B.; Hannigan, J.W.; Sheinberg, H.; Tiainen, T.

    1988-01-01T23:59:59.000Z

    We synthesized amorphous Al/sub 50/Hf/sub 50/ alloy powder by mechanically alloying an equimolar mixture of crystalline powders of Al and Hf using hexane as a dispersant. We characterized the powder as a function of mechanical-alloying time by scanning electron microscopy, x-ray diffraction, and differential scanning calorimetry. Amorphous Al/sub 50/Hf/sub 50/ powder heated at 10 K s/sup /minus/1/ crystallizes polymorphously at 1003 K into orthorhombic AlHf (CrB-type structure). During mechanical alloying, some hexane decomposes and hydrogen and carbon are incorporated into the amorphous alloy powder. The hydrogen can be removed by annealing the powder by hot pressing at a temperature approximately 30 K below the crystallization temperature. The amorphous compacts have a diamond pyramidal hardness of 1025 DPH. 24 refs., 7 figs., 1 tab.

  20. Theoretical Assessment of 178m2Hf De-Excitation

    SciTech Connect (OSTI)

    Hartouni, E P; Chen, M; Descalle, M A; Escher, J E; Loshak, A; Navratil, P; Ormand, W E; Pruet, J; Thompson, I J; Wang, T F

    2008-10-06T23:59:59.000Z

    This document contains a comprehensive literature review in support of the theoretical assessment of the {sup 178m2}Hf de-excitation, as well as a rigorous description of controlled energy release from an isomeric nuclear state.

  1. Bremsstrahlung emission during $?$-decay of $^{226}{\\rm Ra}$

    E-Print Network [OSTI]

    Giorgio Giardina; Giovanni Fazio; Giuseppe Mandaglio; Marina Manganaro; Serghei P. Maydanyuk; Vladislav S. Olkhovsky; Nikolay V. Eremin; Anton A. Paskhalov; Dmitry A. Smirnov; Carmelo Sacca

    2008-04-16T23:59:59.000Z

    We obtained the spectrum of probability of the bremsstrahlung emission accompanying the $\\alpha$-decay of $^{226}{\\rm Ra}$ (E$_{\\alpha}$=4.8 MeV) by measuring the $\\alpha$-$\\gamma$ coincidences and using the model presented in our previous study on the $\\alpha-$decay of $^{214}{\\rm Po}$ (E$_{\\alpha}$=7.7 MeV). We compare the experimental data with the quantum mechanical calculation and find a good agreement between theory and experiment. We discuss the differences between the photon spectra connected with the $\\alpha$-decay of the $^{226}{\\rm Ra}$ and $^{214}{\\rm Po}$ nuclei. For the two mentioned nuclei we analyze the bremsstrahlung emission contributions from the tunneling and external regions of the nucleus barrier into the total spectrum, and we find the destructive interference between these contributions. We also find that the emission of photons during tunneling of the $\\alpha$-particle gives an important contribution to the bremsstrahlung spectrum in the whole E$_{\\gamma}$ energy range of the studied $^{226}$Ra nucleus.

  2. Octupole collectivity in $^{220}$Rn and $^{224}$Ra

    E-Print Network [OSTI]

    Gaffney, Liam Paul

    Collective properties of the radioactive nuclei $^{220}$Rn and $^{224}$Ra have been studied via Coulomb excitation of a $2.8$~A.MeV radioactive ion beam (RIB) incident upon $^{60}$Ni, $^{112,114}$Cd and $^{120}$Sn targets. The experiments took place at the REX-ISOLDE RIB facility, CERN. De-excitation $gamma$-ray yields following multiple-step Coulomb excitation were detected in coincidence with recoiling target nuclei in the Miniball spectrometer. For the first time, $B(E3;3^{+} ightarrow0^{+})$ values have been directly measured with a radioactive ion beam. In the process, $^{224}$Ra becomes the heaviest post-accelerated RIB to date at ISOLDE (with the possible exception of the quasi-stable $^{238}$U). The measurements presented in this thesis represent a tripling of the number of nuclei around $Zsimeq88$ and $Nsimeq134$, for which direct measurements of the octupole collectivity have been performed. The only previous measurements being for the relatively long-lived $^{226}$Ra. The $gamma$-ray yields, in con...

  3. Growth of HfO{sub 2} films using an alternate reaction of HfCl{sub 4} and O{sub 2} under atmospheric pressure

    SciTech Connect (OSTI)

    Takahashi, Naoyuki [Department of Materials Science and Technology, Faculty of Engineering Shizuoka University, 3-5-1 Johoku, Hamamatu, Shizuoka 432-8561 (Japan)]. E-mail: tntakah@ipc.shizuoka.ac.jp; Nonobe, Shinichi [Department of Materials Science and Technology, Faculty of Engineering Shizuoka University, 3-5-1 Johoku, Hamamatu, Shizuoka 432-8561 (Japan); Nakamura, Takato [Department of Materials Science and Technology, Faculty of Engineering Shizuoka University, 3-5-1 Johoku, Hamamatu, Shizuoka 432-8561 (Japan)

    2004-11-01T23:59:59.000Z

    HfO{sub 2} films were deposited onto a Si(100) substrate using an alternate reaction of HfCl{sub 4} and O{sub 2} under atmospheric pressure. Self-limiting growth of the HfO{sub 2} was achieved in the range of the growth temperature above 873K. The X-ray diffraction of the HfO{sub 2} films showed a typical diffraction pattern assigned to the monoclinic polycrystalline phase. Residual chloride concentration in HfO{sub 2} films were not higher than 0.1at%. When the growth temperature was 973K, the HfSiO{sub x} is formed in HfO{sub 2} film. This gives effective permittivity value of 9.6 for the HfO{sub 2} film grown at 573K.

  4. Growth mechanism difference of sputtered HfO{sub 2} on Ge and on Si

    SciTech Connect (OSTI)

    Kita, Koji; Kyuno, Kentaro; Toriumi, Akira [Department of Materials Science, School of Engineering, University of Tokyo 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan)

    2004-07-05T23:59:59.000Z

    HfO{sub 2} films were deposited by the reactive sputtering on Ge and Si substrates simultaneously, and we found both the interface layer and the HfO{sub 2} film were thinner on Ge substrate than those on Si substrate. A metallic Hf layer has a crucial role for the thickness differences of both interface layer and HfO{sub 2} film, since those thickness differences were observed only when an ultrathin metallic Hf layer was predeposited before the reactive sputtering process. The role of metallic Hf in these phenomena is understandable by assuming the formation of a volatile Hf-Ge-O ternary compound at the early stage of the film growth. This result shows that the HfO{sub 2}/Ge system has an advantage over the HfO{sub 2}/Si system from the viewpoint of further reduction of the gate oxide film thickness.

  5. Superlattice Structure and Precipitates in O+ and Zr+ Ion Coimplanted...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    and Zr+ Ion Coimplanted SrTiO3: a Model Waste Form for 90Sr. Abstract: We investigate strontium titanate as a model waste form for 90Sr. Implantation with O+ and Zr+ ions, followed...

  6. Hole Trapping at Surfaces of mZrO2 and mHfO2 Nanocrystals. | EMSL

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: Vegetation ProposedUsingFun withconfinement plasmas in theinPlasticsreductionCuln(1-x)GaxSe2 Solar

  7. Two-Dimensional Polaronic Behavior in the Binary Oxides m-HfO2 and m-ZrO2.

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear SecurityTensile Strain Switched Ferromagnetism in Layeredof Energy Two CompaniesTwo Studies RevealTwoColumn|

  8. The Bayo Canyon/radioactive lanthanum (RaLa) program

    SciTech Connect (OSTI)

    Dummer, J.E.; Taschner, J.C.; Courtright, C.C.

    1996-04-01T23:59:59.000Z

    LANL conducted 254 radioactive lanthanum (RaLa) implosion experiments Sept. 1944-March 1962, in order to test implosion designs for nuclear weapons. High explosives surrounding common metals (surrogates for Pu) and a radioactive source containing up to several thousand curies of La, were involved in each experiment. The resulting cloud was deposited as fallout, often to distances of several miles. This report was prepared to summarize existing records as an aid in evaluating the off-site impact, if any, of this 18-year program. The report provides a historical setting for the program, which was conducted in Technical Area 10, Bayo Canyon about 3 miles east of Los Alamos. A description of the site is followed by a discussion of collateral experiments conducted in 1950 by US Air Force for developing an airborne detector for tracking atmospheric nuclear weapons tests. All known off-site data from the RaLa program are tabulated and discussed. Besides the radiolanthanum, other potential trace radioactive material that may have been present in the fallout is discussed and amounts estimated. Off-site safety considerations are discussed; a preliminary off-site dose assessment is made. Bibliographical data on 33 persons important to the program are presented as footnotes.

  9. E-Print Network 3.0 - atmospheric pressure hf Sample Search Results

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    for: atmospheric pressure hf Page: << < 1 2 3 4 5 > >> 1 Atomic rearrangements in HfO2Si1-xGex interfaces Deok-Yong Cho and S.-J. Oha Summary: by PDA. PDA was per- formed...

  10. Capacitive Behavior of HF Power Transformers: Global Approach to Draw Robust Equivalent Circuits

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    behavior of all components. Among these components, HF power transformers constitute a special case. EvenCapacitive Behavior of HF Power Transformers: Global Approach to Draw Robust Equivalent Circuits of n-windings HF power transformers. A global approach, mainly based on energy considerations about

  11. Effect of Al addition on the microstructure and electronic structure of HfO2 film

    E-Print Network [OSTI]

    Gong, Xingao

    Effect of Al addition on the microstructure and electronic structure of HfO2 film X. F. Wang investigated the microstructures and electronic structures of a series of hafnium aluminate HfAlO films with Al concentration ranging from 0% to 100%. When the films evolve from pure HfO2 to pure Al2O3 by increasing

  12. A correlation between soil descriptions and {sup 226}Ra concentrations in Florida soils

    SciTech Connect (OSTI)

    Harrison, D.P.

    1992-12-31T23:59:59.000Z

    The soil radium content in Florida is highly variable. The range in radium concentrations, where the samples involved in this study are concerned, is from 0.1 pCi/g to 18.5 pCi/g. Low {sup 226}Ra concentrations (0.1 to 5 pCi/g) are evidenced in sands, moderate concentrations (5 to 11 pCi/g) are found in silt and gravel, and high {sup 226}Ra concentrations (>11 pCi/g) are found in soil horizons with shell, clay, and strata with phosphate. Strata containing phosphate yields a high concentration of {sup 226}Ra. The information obtained in this study, soil descriptions with their corresponding {sup 226}Ra concentrations, comes from geological cores drilled by geotechnical consultants with gamma spectrometry analysis performed by high resolution gamma spectroscopy. Concentration; of {sup 226}Ra generally increase with depth. These cores are usually terminated at 20 feet deep, with some cores being shallower than this due to hitting bedrock or encountering the water table. These frequency distributions give the core-logging geologist an approximate concentration of {sup 226}Ra based on the description of the soil. Since the correlation of {sup 226}Ra and soil descriptions can be used as a tool in assigning indoor radon potential, this study is of importance to land managers, contractors, developers, and regulating agencies who are attempting to place standards on tracts of land with {sup 226}Ra concentration used as a criterion.

  13. Comparison of the Ca+HF(DF) and Sr+HF(DF) reaction dynamics Rong Zhang, David J. Rakestraw,a) Kenneth G. McKendrick,b) and Richard N. Zare

    E-Print Network [OSTI]

    Zare, Richard N.

    Comparison of the Ca+HF(DF) and Sr+HF(DF) reaction dynamics Rong Zhang, David J. Rakestraw family, Ca and Sr with rovibrationally selected HF or DF, has been carried out under single-collision conditions. A thermal beam of the alkaline earth atoms, Ca or Sr, is fired into a low-pressure gas of HF

  14. Intrinsic metastability of orthorhombic HfTiO{sub 4} in thin film hafnia-titania

    SciTech Connect (OSTI)

    Cisneros-Morales, Massiel Cristina; Aita, Carolyn Rubin [Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, P.O. Box 413, Milwaukee, Wisconsin 53201 (United States)

    2011-01-31T23:59:59.000Z

    Orthorhombic (o) HfTiO{sub 4} is crystallized when sputter deposited hafnia-titania nanolaminates with ultrathin layers and bilayer (HfO{sub 2}){sub 0.5}(TiO{sub 2}){sub 0.5} composition are annealed between 573 and 1173 K. However, o-HfTiO{sub 4} demixes after annealing at 1273 K, a result not predicted from bulk thermodynamics. X-ray diffraction and Raman microscopy are used here to study structural changes as o-HfTiO{sub 4} demixes upon long-term annealing at 1273 K into Ti-doped monoclinic HfO{sub 2} and Hf-doped rutile TiO{sub 2}. We conclude that o-HfTiO{sub 4} crystallized at low temperature is intrinsically metastable. A space group symmetry analysis shows that demixing can be accomplished by a continuous phase transition chain.

  15. Octupole deformation and Ra puzzle in reflection asymmetric covariant density functional theory

    E-Print Network [OSTI]

    L. F. Yu; P. W. Zhao; S. Q. Zhang; J. Meng

    2012-11-03T23:59:59.000Z

    Reflection asymmetric covariant density functional theory(CDFT) based on the point-coupling interaction is established on a two-center harmonic-oscillator basis and applied to investigate the Ra puzzle, i.e., the anomalous enhancement of the residual proton-neutron interactions for Ra isotopes around N=135. The octupole deformation and shape evolution in the Ra and Rn isotopes are examined in the potential energy surfaces in(beta2, beta3) plane by the constrained reflection asymmetric calculations. The residual proton-neutron interactions extracted from the double difference of the binding energies for Ra isotopes are compared with the data as well as the axial and the triaxial calculations. It is found that the octupole deformation is responsible for the Ra puzzle in the microscopic CDFT.

  16. Compression mode resonances in Zr-90

    E-Print Network [OSTI]

    Youngblood, David H.; Lui, YW; John, B.; Tokimoto, Y.; Clark, HL; Chen, X.

    2004-01-01T23:59:59.000Z

    Compression mode resonances in 90Zr D. H. Youngblood, Y.-W. Lui, B. John,* Y. Tokimoto, H. L. Clark, and X. Chen Cyclotron Institute, Texas A&M University, College Station, Texas 77843, USA (Received 18 February 2004; published 20 May 2004..., JOHN, TOKIMOTO, CLARK, AND CHEN PHYSICAL REVIEW C 69, 054312 (2004) 054312-2 Fig. 2. The continuum distributions are similar over the en- tire energy range, whereas the angular distributions of the cross sections for the peak change...

  17. Growth, microstructure and electrical properties of sputter-deposited hafnium oxide (HfO2) thin films grown using HfO2 ceramic target

    SciTech Connect (OSTI)

    Aguirre, B.; Vemuri, R. S.; Zubia, David; Engelhard, Mark H.; Shutthanandan, V.; Kamala Bharathi, K.; Ramana, Chintalapalle V.

    2011-01-01T23:59:59.000Z

    Hafnium oxide (HfO?) thin films have been made by radio-frequency (rf) magnetron-sputtering onto Si(100) substrates under varying growth temperature (Ts). HfO? ceramic target has been employed for sputtering while varying the Ts from room temperature to 500?C during deposition. The effect of Ts on the growth and microstructure of deposited HfO? films has been studied using grazing incidence x-ray diffraction (GIXRD), X-ray photoelectron spectroscopy (XPS), and high-resolution scanning electron microscopy (HR-SEM) coupled with energy dispersive x-ray spectrometry (EDS). The results indicate that the effect of Ts is significant on the growth, surface and interface structure, morphology and chemical composition of the HfO? films. Structural characterization indicates that the HfO? films grown at Ts<200 ?C are amorphous while films grown at Ts>200 ?C are nanocrystalline. An amorphous-to-crystalline transition occurs at Ts=200 ?C. Nanocrystalline HfO? films crystallized in a monoclinic structure with a (-111) orientation. XPS measurements indicated the high surface-chemical quality and stoichiometric nature of the grown HfO? films. An interface layer (IL) formation occurs due to reaction at the HfO?-Si interface for HfO? films deposited at Ts>200 ?C. The thickness of IL increases with increasing Ts. XPS and EDS at the HfO?-Si cross-section indicate the IL is a (Hf, Si)-O compound. The electrical characterization using capacitance-voltage measurements indicate that the dielectric constant decreases from 25 to 16 with increasing Ts.

  18. Metrological Determination of Natural Radioactive Isotopes {sup 226}Ra, {sup 228}Ra and {sup 210}Pb by Means of Ge Detector

    SciTech Connect (OSTI)

    Almeida, Maria Candida M. de; Delgado, Jose U.; Poledna, Roberto; Oliveira, Estela Maria de; Silva, Ronaldo L. da [Laboratorio Nacional de Metrologia das Radiacoes Ionizantes, Instituto de Radioprotecao e Dosimetria, Comissao Nacional de Energia Nuclear(SEMRA/LNMRI/IRD/CNEN) Av. Salvador Allende s/n, Recreio, Rio de Janeiro, CEP 22780-160, RJ (Brazil)

    2008-08-07T23:59:59.000Z

    A metrological method to determine the activity per mass unity (activity concentration) of {sup 226}Ra and {sup 210}Pb ({sup 238}U decay series) and {sup 228}Ra ({sup 232}Th series) by gamma-ray spectrometers based on hyper-pure coaxial germanium detector was developed. In the soil the {sup 22}Ra (half-life = 1600 years) exhibits the same level of radioactivity as {sup 238}U (half-life 4.5x10{sup 9} years) because of a natural phenomenon called secular equilibrium. {sup 226}Ra decays into {sup 222}Rn (half-life = 3.8 days), a radioactive inert gas. After several days, the {sup 222}Rn naturally decays to {sup 218}Po (half-life = 3 minutes), where finally {sup 210}Pb (half-life = 22 years) is produced. The metrological capability of high-resolution gamma-ray spectrometry for naturally occurring radionuclides at environmental levels is showed, with emphasis on the use of 2 mL standard sources volume in a glass ampoule. Source preparation and calibration procedures are described. Radionuclide standards in an activity range of 10 to 250 Bq/g were produced which can be applied in a variety of environmental sample analysis (water, plant material, sediment, etc.). Uncertainties for {sup 226}Ra and {sup 210}Pb around 3% (k = 1) were obtained.

  19. PoPulation Differentiation anD raPiD evolution of egg Color in aCCorDanCe with Solar raDiation

    E-Print Network [OSTI]

    Lahti, David C.

    PoPulation Differentiation anD raPiD evolution of egg Color in aCCorDanCe with Solar raDiation Davi, . Diferenciación entre Poblaciones y Evolución Rápida del Color de los Huevos de Acuerdo a la Radiación Solar Uy C P' R d Pm wb, ://www.j. m/I.. DOI: 10.1525/k.2008.07033DOI: 10.1525/k.2008.07033 Bird egg color

  20. Audit Report: OAS-RA-13-31 | Department of Energy

    Energy Savers [EERE]

    3-31 Audit Report: OAS-RA-13-31 September 27, 2013 The Department of Energy's Hydrogen and Fuel Cells Program The Department of Energy spent approximately 1 billion over the last...

  1. Ra, a naturally occurring isotope of the 238 U-series with a

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    for counting, liquid scintillation, or mass spectrometry at comparable activities, the simple setup, low cost- fiber and is continuously transferred to a scintillation cham- 226 Ra determination via the rate of 222

  2. Audit Report: OAS-RA-12-12 | Department of Energy

    Energy Savers [EERE]

    2-12 Audit Report: OAS-RA-12-12 May 22, 2012 The Department of Energy's Clean Cities Alternative Fuel Vehicle Grant Program Funded under the American Recovery and Reinvestment Act...

  3. Examination Report: OAS-RA-13-01 | Department of Energy

    Energy Savers [EERE]

    OAS-RA-13-01 October 9, 2012 California Energy Commission - Energy Efficiency and Conservation Block Grant Program Funds Provided by the American Recovery and Reinvestment Act of...

  4. Examination Report: OAS-RA-13-12 | Department of Energy

    Energy Savers [EERE]

    Report: OAS-RA-13-12 February 19, 2013 City of Los Angeles - Energy Efficiency and Conservation Block Grant Program Funds Provided by the American Recovery and Reinvestment Act of...

  5. Examination Report: OAS-RA-13-02 | Department of Energy

    Office of Environmental Management (EM)

    Report: OAS-RA-13-02 October 9, 2012 County of Los Angeles - Energy Efficiency and Conservation Block Grant Program Funds Provided by the American Recovery and Reinvestment Act of...

  6. Audit Report: OAS-RA-11-12 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Audit Report: OAS-RA-11-12 August 22, 2011 The Department of Energy's Weatherization Assistance Program under the American Recovery and Reinvestment Act in the State of Missouri...

  7. Audit Report: OAS-RA-11-14 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Audit Report: OAS-RA-11-14 August 25, 2011 The Department of Energy's Weatherization Assistance Program Funded under the American Recovery and Reinvestment Act for the Commonwealth...

  8. Performance & Risk Assessment Community of Practice (P&RA CoP...

    Energy Savers [EERE]

    an enduring data and modeling resource to minimize duplication of effort across DOE and train future generation of PA professionals In late 2013, the group was broadened as P&RA...

  9. E-Print Network 3.0 - ab initio hf Sample Search Results

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    for: ab initio hf Page: << < 1 2 3 4 5 > >> 1 imageslogoetsf Introduction Electron Energy Loss Spectroscopy Applications: Nanotubes and Graphene Perspectives Summary: of...

  10. Reduced-temperature processing and consolidation of ultra-refractory Ta4HfC5

    SciTech Connect (OSTI)

    Gaballa, Osama [Ames Laboratory; Cook, B. A. [TRI International; Russell, A. M. [Ames Laboratory

    2013-04-26T23:59:59.000Z

    TaC, HfC, and WC powders were subjected to high-energy milling and hot pressing to produce Ta4HfC5, a composite of Ta(4)HfC5 + 30 vol.% WC, and a composite of Ta4HfC5 + 50 vol.% WC. Sub-micron powders were examined after four different milling intervals prior to hot pressing. XRD was used to verify proper phase formation. SEM, relative density, and hardness measurements were used to examine the resulting phases. Hot pressed compacts of Ta4HfC5 showed densification as high as 98.6% along with Vickers hardness values of 21.4 GPa. Similarly, Ta4HfC5 + 30 vol.% WC exhibited 99% densification with a Vickers hardness of 22.5 GPa. These levels of densification were achieved at 1500 degrees C, which is lower than any previously reported sintering temperature for Ta4HfC5. Microhardness values measured in this study were higher than those previously reported for Ta4HfC5. The WC additions to Ta4HfC5 were found to improve densification and increase microhardness. (C) 2013 Elsevier Ltd. All rights reserved.

  11. First In Vivo Evaluation of Liposome-encapsulated 223Ra as a Potential Alpha-particle-emitting Cancer Therapeutic Agent

    SciTech Connect (OSTI)

    Jonasdottir, Thora J.; Fisher, Darrell R.; Borrebaek, Jorgen; Bruland, Oyvind S.; Larsen, Roy H.

    2006-09-13T23:59:59.000Z

    Liposomes carrying chemotherapeutics have had some success in cancer treatment and may be suitable carriers for therapeutic radionuclides. This study was designed to evaluate the biodistribution of and to estimate the radiation doses from the alpha emitter 223Ra loaded into pegylated liposomes in selected tissues. 223Ra was encapsulated in pegylated liposomal doxorubicin by ionophore-mediated loading. The biodistribution of liposomal 223Ra was compared to free cationic 223Ra in Balb/C mice. We showed that liposomal 223 Ra circulated in the blood with an initial half-time in excess of 24 hours, which agreed well with that reported for liposomal doxorubicin in rodents, while the blood half-time of cationic 223Ra was considerably less than one hour. When liposomal 223 Ra was catabolized, the released 223Ra was either excreted or taken up in the skeleton. This skeletal uptake increased up to 14 days after treatment, but did not reach the level seen with free 223Ra. Pre-treatment with non-radioactive liposomal doxorubicin 4 days in advance lessened the liver uptake of liposomal 223 Ra. Dose estimates showed that the spleen, followed by bone surfaces, received the highest absorbed doses. Liposomal 223 Ra was relatively stable in vivo and may have potential for radionuclide therapy and combination therapy with chemotherapeutic agents.

  12. Investigation of abnormal negative threshold voltage shift under positive bias stress in input/output n-channel metal-oxide-semiconductor field-effect transistors with TiN/HfO{sub 2} structure using fast I-V measurement

    SciTech Connect (OSTI)

    Ho, Szu-Han; Chen, Ching-En; Tseng, Tseung-Yuen [Department of Electronics Engineering, National Chiao Tung University, Hsinchu 300, Taiwan (China); Chang, Ting-Chang, E-mail: tcchang@mail.phys.nsysu.edu.tw; Lu, Ying-Hsin; Tsai, Jyun-Yu; Liu, Kuan-Ju [Department of Physics, National Sun Yat-Sen University, Kaohsiung 804, Taiwan (China); Cheng, Osbert; Huang, Cheng-Tung; Lu, Ching-Sen [Device Department, United Microelectronics Corporation, Tainan Science Park, Taiwan (China)

    2014-03-17T23:59:59.000Z

    This letter investigates abnormal negative threshold voltage shifts under positive bias stress in input/output (I/O) TiN/HfO{sub 2} n-channel metal-oxide-semiconductor field-effect transistors using fast I-V measurement. This phenomenon is attributed to a reversible charge/discharge effect in pre-existing bulk traps. Moreover, in standard performance devices, threshold-voltage (V{sub t}) shifts positively during fast I-V double sweep measurement. However, in I/O devices, V{sub t} shifts negatively since electrons escape from bulk traps to metal gate rather than channel electrons injecting to bulk traps. Consequently, decreasing pre-existing bulk traps in I/O devices, which can be achieved by adopting Hf{sub x}Zr{sub 1?x}O{sub 2} as gate oxide, can reduce the charge/discharge effect.

  13. ccsd00001055 First principles study of the solubility of Zr in Al

    E-Print Network [OSTI]

    ccsd­00001055 (version 1) : 22 Jan 2004 First principles study of the solubility of Zr in Al (Dated: January 22, 2004) The experimental solubility limit of Zr in Al is well-known. Al3Zr has a stable the solubility limit of Zr in Al for the stable as well as the metastable phase diagrams. The formation energies

  14. Hf isotope compositions of northern Luzon arc lavas suggest involvement of pelagic sediments in their source

    E-Print Network [OSTI]

    Boyer, Edmond

    1 Hf isotope compositions of northern Luzon arc lavas suggest involvement of pelagic sediments passing through the data intersect fields for depleted mantle and pelagic sediments suggesting. The relationship between Nd and Hf isotopic compositions in the Luzon volcanics show that the type of sediment

  15. Finland HF and Esrange MST radar observations of polar mesosphere summer echoes

    E-Print Network [OSTI]

    Kirkwood, Sheila

    Finland HF and Esrange MST radar observations of polar mesosphere summer echoes Tadahiko Ogawa1 (200x) xx:1­8 Finland HF and Esrange MST radar observations of polar mesosphere summer echoes Tadahiko in Finland are presented. The echoes were detected at four frequencies of 9, 11, 13 and 15 MHz at slant

  16. Interfacial and structural properties of sputtered HfO{sub 2} layers

    SciTech Connect (OSTI)

    Aygun, G. [Department of Physics, Izmir Institute of Technology, Urla, TR-35430 Izmir (Turkey); Yildiz, I. [Department of Physics, Middle East Technical University, TR-06531 Ankara (Turkey); Central Laboratory, Middle East Technical University, TR-06531 Ankara (Turkey)

    2009-07-01T23:59:59.000Z

    Magnetron sputtered HfO{sub 2} layers formed on a heated Si substrate were studied by spectroscopic ellipsometer (SE), x-ray diffraction (XRD), Fourier transform infrared (FTIR), and x-ray photoelectron spectroscopy (XPS) depth profiling techniques. The results show that the formation of a SiO{sub x} suboxide layer at the HfO{sub 2}/Si interface is unavoidable. The HfO{sub 2} thickness and suboxide formation are highly affected by the growth parameters such as sputtering power, O{sub 2}/Ar gas ratio during sputtering, sputtering time, and substrate temperature. XRD spectra show that the deposited film has (111) monoclinic phase of HfO{sub 2}, which is also supported by FTIR spectra. The atomic concentration and chemical environment of Si, Hf, and O have been measured as a function of depth starting from the surface of the sample by XPS technique. It shows that HfO{sub 2} layers of a few nanometers are formed at the top surface. Below this thin layer, Si-Si bonds are detected just before the Si suboxide layer, and then the Si substrate is reached during the depth profiling by XPS. It is clearly understood that the highly reactive sputtered Hf atoms consume some of the oxygen atoms from the underlying SiO{sub 2} to form HfO{sub 2}, leaving Si-Si bonds behind.

  17. A Study of the Grain Boundaries and Hydrogen in HF-CVD Diamond Films

    E-Print Network [OSTI]

    Adler, Joan

    composition of grain boundaries in polycrystalline diamond lms by transmission electron microscopy and highA Study of the Grain Boundaries and Hydrogen in HF-CVD Diamond Films Israel Yoel Koenka #12;A Study of the Grain Boundaries and Hydrogen in HF-CVD Diamond Films Research Thesis In partial fulllment

  18. Ca+HF: The anatomy of a chemical insertion reaction R. L. Jaffe

    E-Print Network [OSTI]

    Zare, Richard N.

    Ca+HF: The anatomy of a chemical insertion reaction R. L. Jaffe NASA Ames Research Center, Moffett theoretical investigation of the gas phase reaction Ca + HF-CaF + H is reported. The overall study involves electronic state of the Ca-F-H system, (b) careful fitting of the computed surface to an analytical form

  19. Ge interactions on HfO{sub 2} surfaces and kinetically driven patterning of Ge nanocrystals on HfO{sub 2}

    SciTech Connect (OSTI)

    Stanley, Scott K.; Joshi, Sachin V.; Banerjee, Sanjay K.; Ekerdt, John G. [Department of Chemical Engineering, University of Texas at Austin, Austin, Texas 78712-0231 (United States); Department of Electrical and Computer Engineering, University of Texas at Austin, Austin, Texas 78712-0240 (United States); Department of Chemical Engineering, University of Texas at Austin, Austin, Texas 78712-0231 (United States)

    2006-01-15T23:59:59.000Z

    Germanium interactions are studied on HfO{sub 2} surfaces, which are prepared through physical vapor deposition (PVD) and by atomic layer deposition. X-ray photoelectron spectroscopy and temperature-programed desorption are used to follow the reactions of germanium on HfO{sub 2}. Germanium chemical vapor deposition at 870 K on HfO{sub 2} produces a GeO{sub x} adhesion layer, followed by growth of semiconducting Ge{sup 0}. PVD of 0.7 ML Ge (accomplished by thermally cracking GeH{sub 4} over a hot filament) also produces an initial GeO{sub x} layer, which is stable up to 800 K. PVD above 2.0 ML deposits semiconducting Ge{sup 0}. Temperature programed desorption experiments of {approx}1.0 ML Ge from HfO{sub 2} at 400-1100 K show GeH{sub 4} desorption below 600 K and GeO desorption above 850 K. These results are compared to Ge on SiO{sub 2} where GeO desorption is seen at 550 K. Exploiting the different reactivity of Ge on HfO{sub 2} and SiO{sub 2} allows a kinetically driven patterning scheme for high-density Ge nanoparticle growth on HfO{sub 2} surfaces that is demonstrated.

  20. Crystal structure of Si-doped HfO{sub 2}

    SciTech Connect (OSTI)

    Zhao, Lili [Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States); School of Information Science and Technology, Northwest University, Xi'an 710127 (China); Department of Materials Science and Engineering, University of Florida, Gainesville, Florida 32611 (United States); Nelson, Matthew; Fancher, Chris M. [Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States); Aldridge, Henry [Department of Materials Science and Engineering, University of Florida, Gainesville, Florida 32611 (United States); Iamsasri, Thanakorn; Forrester, Jennifer S.; Jones, Jacob L., E-mail: jacobjones@ncsu.edu [Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States); Department of Materials Science and Engineering, University of Florida, Gainesville, Florida 32611 (United States); Nishida, Toshikazu [Department of Electrical and Computer Engineering, University of Florida, Gainesville, Florida 32611 (United States); Moghaddam, Saeed [Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, Florida 32611 (United States)

    2014-01-21T23:59:59.000Z

    Si-doped HfO{sub 2} was prepared by solid state synthesis of the starting oxides. Using Rietveld refinement of high resolution X-ray diffraction patterns, a substitutional limit of Si in HfO{sub 2} was determined as less than 9 at.?%. A second phase was identified as Cristobalite (SiO{sub 2}) rather than HfSiO{sub 4}, the latter of which would be expected from existing SiO{sub 2}-HfO{sub 2} phase diagrams. Crystallographic refinement with increased Si-dopant concentration in monoclinic HfO{sub 2} shows that c/b increases, while ? decreases. The spontaneous strain, which characterizes the ferroelastic distortion of the unit cell, was calculated and shown to decrease with increasing Si substitution.

  1. Thermal decomposition of HfCl{sub 4} as a function of its hydration state

    SciTech Connect (OSTI)

    Barraud, E. [Laboratoire de Science et Genie des Materiaux et de Metallurgie, UMR CNRS INPL 7584, Ecole des Mines, F-54042 Nancy Cedex (France); Begin-Colin, S. [Laboratoire de Science et Genie des Materiaux et de Metallurgie, UMR CNRS INPL 7584, Ecole des Mines, F-54042 Nancy Cedex (France) and Institut de Physique et Chimie des Materiaux, GMI, UMR CNRS-ULP 7504, Ecole de Chimie, Polymeres et Materiaux, 23, rue du Loess, BP 43, F-67034 Strasbourg Cedex 2 (France)]. E-mail: begin@ipcms.u-strasbg.fr; Le Caer, G. [Groupe Matiere Condensee et Materiaux, UMR CNRS-Universite de Rennes-I 6626, Campus de Beaulieu, Batiment 11A, F-35042 Rennes Cedex (France); Villieras, F. [Laboratoire Environnement et Mineralurgie, UMR CNRS-INPL 7569, Ecole Nationale Superieure de Geologie de Nancy, F-54501 Vandoeuvre-les-Nancy Cedex (France); Barres, O. [Laboratoire Environnement et Mineralurgie, UMR CNRS-INPL 7569, Ecole Nationale Superieure de Geologie de Nancy, F-54501 Vandoeuvre-les-Nancy Cedex (France)

    2006-06-15T23:59:59.000Z

    The thermogravimetric behavior of HfCl{sub 4} powders with different hydration states has been compared. Strongly hydrated powders consist of HfOCl{sub 2}.nH{sub 2}O with n>4. Partially hydrated powders consist of particles with a HfCl{sub 4} core and a hydrated outerlayer of HfOCl{sub 2}.nH{sub 2}O with n in the range of 0-8. Hydrated powders decomposed at temperature lower than 200 deg. C whereas the decomposition of partially hydrated powders was completed at a temperature of around 450 deg. C. The observed differences in decomposition temperature is related to the structure of HfOCl{sub 2}.nH{sub 2}O, which is different if n is higher or smaller than 4 and leads to intermediate compounds, which decompose at different temperatures.

  2. Safety Slide 1 Hydrofluoric (HF) Acid Hazards http://www.emsworld.com/web/online/Education/Hydrofluoric-Acid-/5$12949

    E-Print Network [OSTI]

    Cohen, Robert E.

    Safety Slide 1 ­ Hydrofluoric (HF) Acid Hazards http://www.emsworld.com/web may be delayed for up to 24 hours, even with dilute solutions. HF burns affect deep tissue layers

  3. Digital hf radar observations of equatorial spread-F

    SciTech Connect (OSTI)

    Argo, P.E.

    1984-01-01T23:59:59.000Z

    Modern digital ionosondes, with both direction finding and doppler capabilities can provide large scale pictures of the Spread-F irregularity regions. A morphological framework has been developed that allows interpretation of the hf radar data. A large scale irregularity structure is found to be nightward of the dusk terminator, stationary in the solar reference frame. As the plasma moves through this foehn-wall-like structure it descends, and irregularities may be generated. Localized upwellings, or bubbles, may be produced, and they drift with the background plasma. The spread-F irregularity region is found to be best characterized as a partly cloudy sky, due to the patchiness of the substructures. 13 references, 16 figures.

  4. DFT STUDY REVISES INTERSTITIAL CONFIGURATIONS IN HCP Zr

    SciTech Connect (OSTI)

    Samolyuk, German D [ORNL; Golubov, Stanislav I [ORNL; Osetskiy, Yury N [ORNL; Stoller, Roger E [ORNL

    2012-06-01T23:59:59.000Z

    Analysis of experimental result on microstructure evolution in irradiated Zr and alloys has demonstrated that available knowledge on self-interstitial defects in Zr is in contradiction. We therefore have initiated an extensive theoretical and modeling program to clarify this issue. In this report we present first ab initio calculations results of single SIA configurations in Zr. We demonstrate importance of simulations cell size, applied exchange-correlation functional and simulated c/a ratio. The results obtained demonstrate clearly that the most stable configurations are in basal plane and provide some evidences for enhanced interstitial transport along basal planes. The results obtained will be used in generation a new interatomic potential for Zr to be used in large-scale atomistic modeling of mechanisms relevant for radiation-induced microstructure evolution.

  5. RAPID METHOD FOR DETERMINATION OF {sup 228}Ra IN WATER SAMPLES

    SciTech Connect (OSTI)

    Maxwell, S.

    2012-09-05T23:59:59.000Z

    A new rapid method for the determination of {sup 228}Ra in natural water samples has been developed at the SRNL/EBL (Savannah River National Lab/ Environmental Bioassay Laboratory) that can be used for emergency response or routine samples. While gamma spectrometry can be employed with sufficient detection limits to determine {sup 228}Ra in solid samples (via {sup 228}Ac) , radiochemical methods that employ gas flow proportional counting techniques typically provide lower MDA (Minimal Detectable Activity) levels for the determination of {sup 228}Ra in water samples. Most radiochemical methods for {sup 228}Ra collect and purify {sup 228}Ra and allow for {sup 228}Ac daughter ingrowth for ~36 hours. In this new SRNL/EBL approach, {sup 228}Ac is collected and purified from the water sample without waiting to eliminate this delay. The sample preparation requires only about 4 hours so that {sup 228}Ra assay results on water samples can be achieved in < 6 hours. The method uses a rapid calcium carbonate precipitation enhanced with a small amount of phosphate added to enhance chemical yields (typically >90%), followed by rapid cation exchange removal of calcium. Lead, bismuth, uranium, thorium and protactinium isotopes are also removed by the cation exchange separation. {sup 228}Ac is eluted from the cation resin directly onto a DGA Resin cartridge attached to the bottom of the cation column to purify {sup 228}Ac. DGA Resin also removes lead and bismuth isotopes, along with Sr isotopes and {sup 90}Y. La is used to determine {sup 228}Ac chemical yield via ICP-MS, but {sup 133}Ba can also be used instead if ICP-MS assay is not available. Unlike some older methods, no lead or strontium holdback carriers or continual readjustment of sample pH is required.

  6. Audit Report: OAS-RA-12-12 | Department of Energy

    Energy Savers [EERE]

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious RankCombustionImprovement3--Logistical5/08 Attendance List1-02 Audit2-02 AuditRA-10-06 Audit22-07RA-12-12

  7. Role of oxygen vacancy in HfO{sub 2}/SiO{sub 2}/Si(100) interfaces

    SciTech Connect (OSTI)

    Cho, Deok-Yong; Oh, S.-J.; Chang, Y.J.; Noh, T.W.; Jung, Ranju; Lee, Jae-Cheol [CSCMR and School of Physics, Seoul National University, Seoul 151-747 (Korea, Republic of); ReCOE and School of Physics, Seoul National University, Seoul 151-747 (Korea, Republic of); Samsung Advanced Institute of Technology, Suwon 440-900 (Korea, Republic of)

    2006-05-08T23:59:59.000Z

    We have investigated the interface states in HfO{sub 2}/SiO{sub 2}/Si(100) systems that were prepared by using the in situ pulsed laser deposition technique. X-ray photoelectron spectroscopy data revealed that when the HfO{sub 2} film thickness exceeds 11 A, the film composition undergoes a systematic change from Hf silicate to oxygen-deficient HfO{sub x<2}. Furthermore, we determined that the evolution of the interface states clearly depends on the oxygen condition applied during the film growth and that the oxygen vacancy is an important parameter for Hf silicate formation.

  8. Towards forming-free resistive switching in oxygen engineered HfO{sub 2?x}

    SciTech Connect (OSTI)

    Sharath, S. U., E-mail: sharath@oxide.tu-darmstadt.de; Kurian, J.; Hildebrandt, E.; Alff, L. [Institute of Materials Science, Technische Universität Darmstadt, Alarich-Weiss-Strasse 2, 64287 Darmstadt (Germany); Bertaud, T.; Walczyk, C.; Calka, P.; Zaumseil, P.; Sowinska, M.; Walczyk, D. [IHP, Im Technologiepark 25, 15236 Frankfurt Oder (Germany); Gloskovskii, A. [Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, 22607 Hamburg (Germany); Schroeder, T. [IHP, Im Technologiepark 25, 15236 Frankfurt Oder (Germany); Brandenburgische Technische Universität, Konrad-Zuse-Strasse 1, 03046 Cottbus (Germany)

    2014-02-10T23:59:59.000Z

    We have investigated the resistive switching behavior in stoichiometric HfO{sub 2} and oxygen-deficient HfO{sub 2?x} thin films grown on TiN electrodes using reactive molecular beam epitaxy. Oxygen defect states were controlled by the flow of oxygen radicals during thin film growth. Hard X-ray photoelectron spectroscopy confirmed the presence of sub-stoichiometric hafnium oxide and defect states near the Fermi level. The oxygen deficient HfO{sub 2?x} thin films show bipolar switching with an electroforming occurring at low voltages and low operating currents, paving the way for almost forming-free devices for low-power applications.

  9. Low energy N{sub 2} ion bombardment for removal of (HfO{sub 2}){sub x}(SiON){sub 1-x} in dilute HF

    SciTech Connect (OSTI)

    Hwang, Wan Sik; Cho, Byung-Jin; Chan, Daniel S. H.; Yoo, Won Jong [Silicon Nano Device Laboratory, Department of Electrical and Computer Engineering, National University of Singapore, E4A 02-04, Engineering Drive 3, 117576 Singapore (Singapore); SKKU Advanced Institute of Nanotechnology (SAINT) and Department of Mechanical Engineering, Sungkyunkwan University 300 Cheoncheon-dong, Jangan-gu, Suwon, Gyeonggi-do 440-746 (Korea, Republic of)

    2007-07-15T23:59:59.000Z

    The ion assisted wet removal of (HfO{sub 2}){sub x}(SiON){sub 1-x} high dielectric constant (k) materials and its effect on electrical properties were investigated. Crystallization temperature of (HfO{sub 2}){sub x}(SiON){sub 1-x} increased as the percentage of SiON increased. The crystallized (HfO{sub 2}){sub 0.6}(SiON){sub 0.4} was damaged and turned to an amorphous film via incorporation of N species into the film by N{sub 2} plasma treatment. In addition, the structure of (HfO{sub 2}){sub 0.6}(SiON){sub 0.4} was disintegrated into HfO{sub 2}, SiO(N), and ON after N{sub 2} plasma treatment. N{sub 2} plasmas using low bias power were applied for wet removal of high-k films and the mechanism of the ion assisted wet removal process was explored. When high bias power was applied, the surface of source and drain regions was nitrided via the reaction between N and Si substrates. Feasibility of the low bias power assisted wet removal process was demonstrated for short channel high-k metal oxide semiconductor device fabrication by the smaller shift of threshold voltage, compared to the high bias power assisted wet removal process as well as the wet-etching-only process.

  10. Mixed cation phases in sputter deposited HfO{sub 2}-TiO{sub 2} nanolaminates

    SciTech Connect (OSTI)

    Cisneros-Morales, M. C.; Aita, C. R. [Advanced Coatings Experimental Laboratory, College of Engineering and Applied Science, University of Wisconsin-Milwaukee, P.O. Box 784, Milwaukee, Wisconsin 53201 (United States)

    2008-07-14T23:59:59.000Z

    Nanolaminate HfO{sub 2}-TiO{sub 2} films are grown by reactive sputter deposition on unheated fused SiO{sub 2}, sequentially annealed at 573 to 973 K, and studied by x-ray diffraction. A nanocrystalline structure of orthorhombic (o) HfTiO{sub 4} adjacent to an interface followed by monoclinic (m) Hf{sub 1-x}Ti{sub x}O{sub 2} is identified. m-Hf{sub 1-x}Ti{sub x}O{sub 2}, a metastable phase, is isomorphous with m-HfO{sub 2} and a high pressure phase, m-HfTiO{sub 4}. A Vegard's law analysis shows that the Ti atomic fraction in m-Hf{sub 1-x}Ti{sub x}O{sub 2} is much greater than Ti equilibrium solubility in m-HfO{sub 2}. A space group-subgroup argument proposes that m-Hf{sub 1-x}Ti{sub x}O{sub 2} arises from an o/m-HfTiO{sub 4} second order phase transition to accommodate the larger Hf atom.

  11. Suppression of interfacial reaction for HfO{sub 2} on silicon by pre-CF{sub 4} plasma treatment

    SciTech Connect (OSTI)

    Lai, C.S.; Wu, W.C.; Chao, T.S.; Chen, J.H.; Wang, J.C.; Tay, L.-L.; Rowell, Nelson [Department of Electronic Engineering, Chang Gung University, 259 Wen-Hwa 1st Road, Kwei-Shan, Tao-Yuan 333, Taiwan (China); Department of Electronic Physics, National Chiao Tung University, 1001 Ta Hsueh Rd., Hsinchu 300, Taiwan (China); Department of Electronics Engineering, National Chiao Tung University, 1001 Ta Hsueh Rd., Hsinchu 300, Taiwan (China); Nanya Technology Corporation, Hwa-Ya Technology Park, 669 Fu-Hsing 3rd Rd., Kueishan, Taoyuan 338, Taiwan (China); Institute for Microstructural Sciences, National Research Council of Canada, 1200 Montreal Road, Ottawa, Ontario K1A 0R6 (Canada)

    2006-08-14T23:59:59.000Z

    In this letter, the effects of pre-CF{sub 4} plasma treatment on Si for sputtered HfO{sub 2} gate dielectrics are investigated. The significant fluorine was incorporated at the HfO{sub 2}/Si substrate interface for a sample with the CF{sub 4} plasma pretreatment. The Hf silicide was suppressed and Hf-F bonding was observed for the CF{sub 4} plasma pretreated sample. Compared with the as-deposited sample, the effective oxide thickness was much reduced for the pre-CF{sub 4} plasma treated sample due to the elimination of the interfacial layer between HfO{sub 2} and Si substrate. These improved characteristics of the HfO{sub 2} gate dielectrics can be explained in terms of the fluorine atoms blocking oxygen diffusion through the HfO{sub 2} film into the Si substrate.

  12. Supply of purified Th228 for Ra224 generators. Final CRADA Report .

    SciTech Connect (OSTI)

    Ehst, D. A.; Nuclear Engineering Division

    2009-10-02T23:59:59.000Z

    CRADA was terminated when it was determined that the Russians could not perform the terms of the subcontract. It became apparent that the Russians would not be a reliable source of Th228, as a precursor in the decay chain which leads to Ra224. Their government policies will prohibit the export of Th228 in quantities needed for commercial cancer therapy.

  13. George Feher (Photograph by R.A. Icaacson) Photosynthesis Research 55: 140, 1998.

    E-Print Network [OSTI]

    Govindjee "Gov"

    George Feher (Photograph by R.A. Icaacson) #12;Photosynthesis Research 55: 1­40, 1998. © 1998 of research in bacterial photosynthesis and the road leading to it: A personal account George Feher In this minireview I present a very personal account of my life and research in bacterial photosynthesis

  14. RaWMS -Random Walk based Lightweight Membership Service for Wireless Ad Hoc Networks

    E-Print Network [OSTI]

    Tomkins, Andrew

    : Algorithms, Design Additional Key Words and Phrases: Ad Hoc Networks, Membership service, Random Walk 1. INTRODUCTION Context of this study. Membership services serve as essential building blocks in a varietyRaWMS - Random Walk based Lightweight Membership Service for Wireless Ad Hoc Networks ZIV BAR

  15. RA After Hours On Call (971) 246-1388 Your Guide to

    E-Print Network [OSTI]

    Latiolais, M. Paul

    for the resident to pick up at the move-in station. Laundry Laundry facilities are located on odd-numbered floors is on for an extended amount of time, please notify the Help desk or the RA on call. If you leave trash, abandoned

  16. RaPID: THE END OF HEURISTIC PID TUNING Peter Van Overschee, Christiaan Moons, Wim Van Brempt

    E-Print Network [OSTI]

    RaPID: THE END OF HEURISTIC PID TUNING Peter Van Overschee, Christiaan Moons, Wim Van Brempt Paul Vanvuchelen, Bart De Moor Abstract: RaPID (Robust Advanced PID Control) is a new and original engineer- ing tool for the design and implementation of optimal PID controllers. It integrates data acquisition

  17. Germanium diffusion during HfO{sub 2} growth on Ge by molecular beam epitaxy

    SciTech Connect (OSTI)

    Ferrari, S.; Spiga, S.; Wiemer, C.; Fanciulli, M.; Dimoulas, A. [Laboratorio MDM-INFM-CNR, Via Olivetti, 2 Agrate Brianza, Milano 20041 (Italy); MBE Laboratory, Institute of Materials Science, DEMOKRITOS National Center for Scientific Research, 153 10 Athens (Greece)

    2006-09-18T23:59:59.000Z

    The authors study the Ge diffusion during HfO{sub 2} growth by molecular beam epitaxy on differently in situ prepared germanium substrates and at different growth temperatures. While HfO{sub 2} layers grown directly on Ge do not show any germanium contamination, oxygen rich interfacial layers such as GeO{sub x} or GeO{sub x}N{sub y} partly dissolve into the HfO{sub 2} layer, giving rise to high Ge contamination (from 1% to 10%). The use of nitridated interfacial layers does not prevent Ge diffusion into the HfO{sub 2} during the growth process because of the high oxygen content present in the nitridated germanium layer.

  18. In situ characterization of initial growth of HfO{sub 2}

    SciTech Connect (OSTI)

    Wang, L.; Chu, Paul K. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon (Hong Kong); Xue, K.; Xu, J. B. [Department of Electronic Engineering, Chinese University of Hong Kong, Shatin, New Territories (Hong Kong)

    2009-01-19T23:59:59.000Z

    The initial growth of HfO{sub 2} on Si (111) is monitored in situ by ultrahigh vacuum (UHV) scanning probe microscopy. UHV scanning tunneling microscopy and UHV atomic force microscopy reveal the topography of HfO{sub 2} films in the initial stage. The chemical composition is further confirmed by x-ray photoelectron spectroscopy. Scanning tunneling spectroscopy is utilized to inspect the evolution of the bandgap. When the film thickness is less than 0.6 nm, the bandgap of HfO{sub 2} is not completely formed. A continuous usable HfO{sub 2} film with thickness of about 1.2 nm is presented in this work.

  19. LuHf isotope systematics of fossil biogenic apatite and their effects on geochronology

    E-Print Network [OSTI]

    Schöne, Bernd R.

    ) and argillaceous matrices with low permeability (oil shale of Messel, Germany; Posidonienschiefer of Holzmaden the Eifel, Germany. Low 176 Lu/177 Hf ratios in all materials from the Middle Eocene Messel oil shale (e

  20. Plasma etching of HfO{sub 2} at elevated temperatures in chlorine-based chemistry

    SciTech Connect (OSTI)

    Helot, M.; Chevolleau, T.; Vallier, L.; Joubert, O.; Blanquet, E.; Pisch, A.; Mangiagalli, P.; Lill, T. [STMicroelectronics, 850 rue Jean Monnet, 38926 Crolles Cedex (France); Laboratoire des Technologies de la Microelectronique, CNRS, 17 rue des martyrs (CEA-LETI), 38054 Grenoble Cedex 09 (France); LTPCM/INPG-CNRS-UJF, 1130 rue de la piscine, 38402 Saint-Martin-d'Heres (France); Applied Materials, 974 E. Arques Ave. M/S 81334, Sunnyvale, California 94086 (United States)

    2006-01-15T23:59:59.000Z

    Plasma etching of HfO{sub 2} at an elevated temperature is investigated in chlorine-based plasmas. Thermodynamic studies are performed in order to determine the most appropriate plasma chemistry. The theoretical calculations show that chlorocarbon gas chemistries (such as CCl{sub 4} or Cl{sub 2}-CO) can result in the chemical etching of HfO{sub 2} in the 425-625 K temperature range by forming volatile effluents such as HfCl{sub 4} and CO{sub 2}. The etching of HfO{sub 2} is first studied on blanket wafers in a high density Cl{sub 2}-CO plasma under low ion energy bombardment conditions (no bias power). Etch rates are presented and discussed with respect to the plasma parameters. The evolution of the etch rate as function of temperature follows an Arrhenius law indicating that the etching comes from chemical reactions. The etch rate of HfO{sub 2} is about 110 A /min at a temperature of 525 K with a selectivity towards SiO{sub 2} of 15. x-ray photoelectron spectroscopy analyses (XPS) reveal that neither carbon nor chlorine is detected on the HfO{sub 2} surface, whereas a chlorine-rich carbon layer is formed on top of the SiO{sub 2} surface leading to the selectivity between HfO{sub 2} and SiO{sub 2}. A drift of the HfO{sub 2} etch process is observed according to the chamber walls conditioning due to chlorine-rich carbon coatings formed on the chamber walls in a Cl{sub 2}-CO plasma. To get a very reproducible HfO{sub 2} etch process, the best conditioning strategy consists in cleaning the chamber walls with an O{sub 2} plasma between each wafer. The etching of HfO{sub 2} is also performed on patterned wafers using a conventional polysilicon gate. The first result show a slight HfO{sub 2} foot at the bottom of the gate and the presence of hafnium oxide-based residues in the active areas.

  1. Subduction Controls of Hf and Nd Isotopes in Lavas of the Aleutian Island Arc

    SciTech Connect (OSTI)

    Yogodzinski, Gene; Vervoort, Jeffery; Brown, Shaun Tyler; Gerseny, Megan

    2010-08-29T23:59:59.000Z

    The Hf and Nd isotopic compositions of 71 Quaternary lavas collected from locations along the full length of the Aleutian island arc are used to constrain the sources of Aleutian magmas and to provide insight into the geochemical behavior of Nd and Hf and related elements in the Aleutian subduction-magmatic system. Isotopic compositions of Aleutian lavas fall approximately at the center of, and form a trend parallel to, the terrestrial Hf-Nd isotopic array with {var_epsilon}{sub Hf} of +12.0 to +15.5 and {var_epsilon}{sub Nd} of +6.5 to +10.5. Basalts, andesites, and dacites within volcanic centers or in nearby volcanoes generally all have similar isotopic compositions, indicating that there is little measurable effect of crustal or other lithospheric assimilation within the volcanic plumbing systems of Aleutian volcanoes. Hafnium isotopic compositions have a clear pattern of along-arc increase that is continuous from the eastern-most locations near Cold Bay to Piip Seamount in the western-most part of the arc. This pattern is interpreted to reflect a westward decrease in the subducted sediment component present in Aleutian lavas, reflecting progressively lower rates of subduction westward as well as decreasing availability of trench sediment. Binary bulk mixing models (sediment + peridotite) demonstrate that 1-2% of the Hf in Aleutian lavas is derived from subducted sediment, indicating that Hf is mobilized out of the subducted sediment with an efficiency that is similar to that of Sr, Pb and Nd. Low published solubility for Hf and Nd in aqueous subduction fluids lead us to conclude that these elements are mobilized out of the subducted component and transferred to the mantle wedge as bulk sediment or as a silicate melt. Neodymium isotopes also generally increase from east to west, but the pattern is absent in the eastern third of the arc, where the sediment flux is high and increases from east to west, due to the presence of abundant terrigenous sediment in the trench east of the Amlia Fracture Zone, which is being subducting beneath the arc at Seguam Island. Mixing trends between mantle wedge and sediment end members become flatter in Hf-Nd isotope space at locations further west along the arc, indicating that the sediment end member in the west has either higher Nd/Hf or is more radiogenic in Hf compared to Nd. This pattern is interpreted to reflect an increase in pelagic clay relative to the terrigenous subducted sedimentary component westward along the arc. Results of this study imply that Hf does not behave as a conservative element in the Aleutian subduction system, as has been proposed for some other arcs.

  2. Chemical states and electronic structure of a HfO(-2) / Ge(001) interface

    SciTech Connect (OSTI)

    Seo, Kang-ill; McIntyre, Paul C.; /Stanford U., Materials Sci. Dept.; Sun, Shiyu; Lee, Dong-Ick; Pianetta, Piero; /SLAC, SSRL; Saraswat, Krishna C.; /Stanford U., Elect.

    2005-05-04T23:59:59.000Z

    We report the chemical bonding structure and valence band alignment at the HfO{sub 2}/Ge (001) interface by systematically probing various core level spectra as well as valence band spectra using soft x-rays at the Stanford Synchrotron Radiation Laboratory. We investigated the chemical bonding changes as a function of depth through the dielectric stack by taking a series of synchrotron photoemission spectra as we etched through the HfO{sub 2} film using a dilute HF-solution. We found that a very non-stoichiometric GeO{sub x} layer exists at the HfO{sub 2}/Ge interface. The valence band spectra near the Fermi level in each different film structure were carefully analyzed, and as a result, the valence band offset between Ge and GeO{sub x} was determined to be {Delta}E{sub v} (Ge-GeO{sub x}) = 2.2 {+-} 0.15 eV, and that between Ge and HfO{sub 2}, {Delta}E{sub v} (Ge-HfO{sub 2}) = 2.7 {+-} 0.15 eV.

  3. HfO{sub x}N{sub y} gate dielectric on p-GaAs

    SciTech Connect (OSTI)

    Dalapati, G. K.; Sridhara, A.; Wong, A. S. W.; Chia, C. K.; Chi, D. Z. [Institute of Materials Research and Engineering, A-STAR - Agency for Science, Technology and Research, 3 Research Link, Singapore 117602 (Singapore)

    2009-02-16T23:59:59.000Z

    Plasma nitridation method is used for nitrogen incorporation in HfO{sub 2} based gate dielectrics for future GaAs-based devices. The nitrided HfO{sub 2} (HfO{sub x}N{sub y}) films on p-GaAs improve metal-oxide-semiconductor device characteristics such as interface state density, accumulation capacitance, hysteresis, and leakage current. An equivalent oxide thickness of 3.6 nm and a leakage current density of 10{sup -6} A cm{sup -2} have been achieved at V{sub FB}-1 V for nitrided HfO{sub 2} films. A nitride interfacial layer (GaAsO:N) was observed at HfO{sub 2}-GaAs interface, which can reduce the outdiffusion of elemental Ga and As during post-thermal annealing process. Such suppression of outdiffusion led to a substantial enhancement in the overall dielectric properties of the HfO{sub 2} film.

  4. Targeting of Osseous Sites with Alpha-emitting Ra-223: Comparison with the Beta-emitter Sr-89 in Mice

    SciTech Connect (OSTI)

    Henriksen, Gjermund; Fisher, Darrell R.; Roeske, John C.; Bruland, Oyvind S.; Larsen, Roy H.

    2003-05-16T23:59:59.000Z

    The bone-seeking property of and the potential to irradiate red marrow by the alpha-particle emitter Ra-223 (t1/2 = 11.43 d) were compared to those of the beta-emitter Sr-89 (t1/2 = 50.53 d). Methods: The biodistributions of Ra-223 and Sr-89 were studied in mice. Tissue uptakes were determined at 1 h, 6 h, 1 d, 3 d, and 14 d after intravenous administration. The potential redistribution of progeny from Ra-223 located in bone was investigated. Radiation absorbed doses were calculated for soft tissues and bone. Doses were also estimated for marrow-containing cavities assuming spheric geometries. Results: We found that both Sr-89 and Ra-223 selectively concentrated on bone surfaces relative to soft tissues. The measured bone uptake of Ra-223 was slightly higher than that of Sr-89. At the 24 h time-point, the femur uptake of Ra-223 was 40.1% of the administered activity per gram tissue. The uptake in spleen and most other soft tissues was higher for Ra-223 than for Sr-89. We observed rapid clearance of Ra-223 from soft tissues within the first 24 hours, but the bone surface uptake of Ra-223 increased with time up to 24 h. Among the soft tissues, the spleen had the greatest accumulation and retention of Ra-223. The femur-to-spleen ratio increased with time, from 6.4 at 6 h to 23.7 at 3 days after injections. We found little redistribution of Ra-223 daughter products away from bone (about 2% at 6 h and less than 1% detectable at 3 d). Estimates of dose to marrow-containing cavities showed that the Ra-223 alpha-emitter might have a marrow-sparing advantage compared to beta-emitters due to high linear-energy-transfer and short alpha range targeting osteoid surfaces. The alpha-emitters irradiate a smaller fraction of the marrow-containing volumes--sparing marrow and enhancing survival of marrow cells. At the same time, the bone surfaces receives a therapeutically effective radiation dose. Conclusion: The results of this study indicate that Ra-223 is a promising candidate for high linear-energy-transfer alpha-particle irradiation of cancer cells on bone surfaces. Radium-223 can, together with its daughter radionuclides, deliver an intense and highly localized field of radiation to bone surfaces with substantially less irradiation of healthy bone marrow dose compared to standard, bone-seeking beta-emitters such as Sr-89.

  5. Characterization of Zr-Fe-Cu Alloys for an Inert Matrix Fuel for Nuclear Energy Applications

    E-Print Network [OSTI]

    Barnhart, Brian A.

    2013-08-09T23:59:59.000Z

    Cu had the largest melting temperature (886.3°C) while Zr-12Fe-10Cu had the smallest melting temperature (870°C). The third alloy, Zr-12Fe-15Cu, had a melting point just below that of Zr-12Fe-5Cu at 882.7°C. Light Flash Analysis (LFA...

  6. ccsd00001116 Nucleation of Al 3 Zr and Al 3 Sc in aluminum alloys

    E-Print Network [OSTI]

    ccsd­00001116 (version 1) : 4 Feb 2004 Nucleation of Al 3 Zr and Al 3 Sc in aluminum alloys: from 4, 2004) Zr and Sc precipitate in aluminum alloys to form the compounds Al3Zr and Al3Sc which

  7. Nuclear fusion as a probe for octupole deformation in $^{224}$Ra

    E-Print Network [OSTI]

    Kumar, Raj; Vitturi, A

    2015-01-01T23:59:59.000Z

    $\\textit{Background}$: Nuclear fusion has been shown to be a perfect probe to study the different nuclear shapes. However, the possibility of testing octupole deformation of a nucleus with this tool has not been fully explored yet. The presence of a stactic octupole deformation in nuclei will enhanced a possible permanent electric dipole moment, leading to a possible demonstration of parity violation. $\\textit{Purpose}$: To check whether static octupole deformation or octupole vibration in fusion give qualitatively different results so that both situations can be experimentally disentangled. $\\textit{Method}$: Fusion cross sections are computed in the Coupled-Channels formalism making use of the Ingoing-Wave Boundary Conditions (IWBC) for the systems $^{16}$O+$^{144}$Ba and $^{16}$O+$^{224}$Ra. $\\textit{Results}$: Barrier distributions of the two considered schemes show different patterns. For the $^{224}$Ra case, the octupole deformation parameter is large enough to create a sizeable difference. $\\textit{Con...

  8. Calculo Numerico (MS211) PROVA 1 (25/09/2012) Nome: RA: Turma

    E-Print Network [OSTI]

    Sussner, Peter

    C´alculo Num´erico (MS211) PROVA 1 (25/09/2012) Nome: RA: Turma: Trabalhe com radianos e 4 d boa aproxima¸c~ao de uma solu¸c~ao pode ser encontrada atrav´es o m´etodo de Newton(-Raphson). Se for poss´ivel, execute duas itera¸c~oes do m´etodo de Newton(-Raphson) gr´aficamente para cada um dos

  9. Calculo Numerico (MS211) PROVA 1 (19/04/2010) Nome: RA: Turma

    E-Print Network [OSTI]

    Sussner, Peter

    C´alculo Num´erico (MS211) PROVA 1 (19/04/2010) Nome: RA: Turma: Trabalhe com 4 d´igitos decimais desta equa¸c~ao utilizando o M´etodo de Newton- Raphson com x0 = 2.5 e precis~oes 1 = 2 = 10. [0.5 pts] (c) Se tomarmos x0 = 1.01 como ser´a o comportamento da sequ^encia gerada pelo M´etodo de

  10. Calculo Numerico (MS211) PROVA 1 (01/10/2013) Nome: RA: Turma: Y

    E-Print Network [OSTI]

    Sussner, Peter

    ] (c) Em qual dos m´etodos n´umericos que voc^e conhece geralmente se usa a fatora¸c~ao LU (com ou semC´alculo Num´erico (MS211) PROVA 1 (01/10/2013) Nome: RA: Turma: Y Trabalhe com radianos e 4 d = b fazendo todas as contas na maquina. Explicite as opera¸c~oes bin´arias que produzem erros num´ericos

  11. 225-Ac and 223-Ra Production via 800 MeV Proton Irradiation of Natural Thorium Target

    E-Print Network [OSTI]

    J. W. Weidner; S. G. Mashnik; K. D. John; B. Ballard; E. R. Birnbaum; L. J. Bitteker; A. Couture; M. E. Fassbender; G. S. Goff; R. Gritzo; F. M. Hemez; W. Runde; J. L. Ullmann; L. E. Wolfsberg; F. M. Nortier

    2012-04-10T23:59:59.000Z

    Cross sections for the formation of 225,227-Ac, 223,225-Ra, and 227-Th via the proton bombardment of natural thorium targets were measured at a nominal proton energy of 800 MeV. No earlier experimental cross section data for the production of 223,225-Ra, 227-Ac and 227-Th by this method were found in the literature. A comparison of theoretical predictions with the experimental data shows agreement within a factor of two. Results indicate that accelerator-based production of 225-Ac and 223-Ra is a viable production method.

  12. A New Environmentally Friendly AL/ZR-Based Clay Stabilizer

    E-Print Network [OSTI]

    El-Monier, Ilham Abdallah

    2013-01-18T23:59:59.000Z

    Clay stabilizers are means to prevent fines migration and clay swelling, which are caused by the contact of formation with low salinity or high pH brines at high temperature. Previous clay stabilizers including: Al and Zr compounds and cationic...

  13. Thermally-driven H interaction with HfO{sub 2} films deposited on Ge(100) and Si(100)

    SciTech Connect (OSTI)

    Soares, G. V., E-mail: gabriel.soares@ufrgs.br; Feijó, T. O. [Instituto de Física, UFRGS, Porto Alegre 91509-900 (Brazil); Baumvol, I. J. R. [Instituto de Física, UFRGS, Porto Alegre 91509-900 (Brazil); Universidade de Caxias do Sul, Caxias do Sul 95070-560 (Brazil); Aguzzoli, C. [Universidade de Caxias do Sul, Caxias do Sul 95070-560 (Brazil); Krug, C. [Instituto de Física, UFRGS, Porto Alegre 91509-900 (Brazil); CEITEC S.A., Porto Alegre 91550-000 (Brazil); Radtke, C. [Instituto de Química, UFRGS, Porto Alegre 91509-900 (Brazil)

    2014-01-27T23:59:59.000Z

    In the present work, we investigated the thermally-driven H incorporation in HfO{sub 2} films deposited on Si and Ge substrates. Two regimes for deuterium (D) uptake were identified, attributed to D bonded near the HfO{sub 2}/substrate interface region (at 300?°C) and through the whole HfO{sub 2} layer (400–600?°C). Films deposited on Si presented higher D amounts for all investigated temperatures, as well as, a higher resistance for D desorption. Moreover, HfO{sub 2} films underwent structural changes during annealings, influencing D incorporation. The semiconductor substrate plays a key role in this process.

  14. Correlation between corrosion performance and surface wettability in ZrTiCuNiBe bulk metallic glasses

    E-Print Network [OSTI]

    Zheng, Yufeng

    Correlation between corrosion performance and surface wettability in ZrTiCuNiBe bulk metallic June 2010 The corrosion properties of two Zr-based bulk metallic glass, Zr41Ti14Cu12Ni10Be23 LM1 and Zr potential, LM1b showed superior corrosion resistance to LM1. Under identical sample preparation and testing

  15. Determination of the chemistry of HF acidizing with the use of {sup 19}F NMR spectroscopy

    SciTech Connect (OSTI)

    Shuchart, C.E.; Buster, D.C.

    1995-11-01T23:59:59.000Z

    A more thorough understanding of the chemistry of HF acid and its reaction products on silica and alumino-silicates is essential to the design and optimization of HF acidizing treatments. To more clearly define the chemistry of HF acidizing, an in-depth investigation of the reaction of HF and H{sub 2}SiF{sub 6} with alumino-silicates was undertaken using {sup 19}F Nuclear Magnetic Resonance (NMR) spectroscopy. In addition to the fluosilicic acid (H{sub 2}SiF{sub 6}) and AlF{sup 2+} predicted by traditional theories, {sup 19}F NMR spectroscopy shows a complex mixture of silicon and aluminum fluoride species in reacted HF acidizing solutions. During a secondary reaction of silicon fluorides with alumino-silicates, a constant F/Al ratio was maintained until the silicon fluorides had reacted completely. The distribution of the fluoride species depends on the HCl concentration. In this investigation, a tertiary reaction of HF acid on alumino-silicates was identified. When the silicon fluorides have reacted completely to give silica gel, the aluminum fluoride complexes continue to react on fresh alumino-silicates. The reaction causes the aluminum content to increase and the F/Al ratio and acid concentration to decrease. The final F/Al ratio is dependent upon acid strength and temperature. Numerous HF acidizing well returns have been analyzed to verify the reactions conducted in the laboratory. The extent of the reaction of HF acid can be determined with the use of {sup 19}F NMR spectroscopy. In wells with temperatures of 150 to 200 F, the reaction of H{sub 2}SiF{sub 6} is complete. Silicon content was quite low, and pH levels were 2 to 3. The F/Al ratios of the returns were 0.5 to 1.3, depending on the concentration of HCl and HF used in the treatment. In wells less than 100 F, the secondary reaction did not go to completion. Silicon and aluminum fluoride complexes were present in the returns along with live HCl.

  16. Spectroscopic analysis of Al and N diffusion in HfO{sub 2}

    SciTech Connect (OSTI)

    Lysaght, P. S.; Price, J.; Kirsch, P. D. [SEMATECH, 257 Fuller Rd, Albany, New York 12203 (United States); Woicik, J. C.; Weiland, C. [National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); Sahiner, M. A. [Seton Hall University, 400 South Orange Ave, South Orange, New Jersey 07079 (United States)

    2012-09-15T23:59:59.000Z

    X-ray photoelectron core level spectroscopy, secondary ion mass spectroscopy, spectroscopic ellipsometry, and extended x-ray absorption fine structure measurements have been employed to distinguish the effects of Al and N diffusion on the local bonding and microstructure of HfO{sub 2} and its interface with the Si substrate in (001)Si/SiO{sub x}/2 nm HfO{sub 2}/1 nm AlO{sub x} film structures. The diffusion of Al from the thin AlO{sub x} cap layer deposited on both annealed and unannealed HfO{sub 2} has been observed following anneal in N{sub 2} and NH{sub 3} ambient. Both N{sub 2} and NH{sub 3} subsequent anneals were performed to decouple incorporated nitrogen from thermal reactions alone. Causal variations in the HfO{sub 2} microstructure combined with the dependence of Al and N diffusion on initial HfO{sub 2} conditions are presented with respect to anneal temperature and ambient.

  17. HF treatment effect for carbon deposition on silicon (111) by DC sputtering technique

    SciTech Connect (OSTI)

    Aji, A. S., E-mail: aji.ravazes70@gmail.com; Darma, Y., E-mail: aji.ravazes70@gmail.com [Quantum Semiconductor and Devices Lab., Physics of Material Electronics Research Division, Department of Physics, Institut Teknologi Bandung (Indonesia)

    2014-03-24T23:59:59.000Z

    Surface modifications of Si (111) substrate by HF solution for thin film carbon deposition have been systematically studied. Thin film carbon on Si (111) has been deposited using DC Unbalanced Magnetron Sputtering with carbon pellet doped by 5% Fe as the target. EDAX characterization confirmed that the carbon fraction on Si substrate much higher by dipping a clean Si substrate by HF solution before sputtering process in comparison with carbon fraction on Si substrate just after conventional RCA. Moreover, SEM and AFM images show the uniform thin film carbon on Si with HF treatment, in contrast to the Si without HF solution treatment. These experimental results suggest that HF treatment of Si surface provide Si-H bonds on top Si surface that useful to enhance the carbon deposition during sputtering process. Furthermore, we investigate the thermal stability of thin film carbon on Si by thermal annealing process up to 900 °C. Atomic arrangements during annealing process were characterized by Raman spectroscopy. Raman spectra indicate that thin film carbon on Si is remaining unchanged until 600 °C and carbon atoms start to diffuse toward Si substrate after annealing at 900 °C.

  18. Characteristics of Hf-silicate thin films synthesized by plasma enhanced atomic layer deposition

    SciTech Connect (OSTI)

    Liu Jiurong; Martin, Ryan M.; Chang, Jane P. [Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, California 90095 (United States)

    2008-09-15T23:59:59.000Z

    Hafnium silicate films were grown by alternating the deposition cycles of hafnium oxide and silicon oxide using a plasma enhanced atomic layer deposition process. The as-deposited and 900 deg. C annealed hafnium silicate films were determined to be amorphous using grazing incidence x-ray diffraction. This suggested that the formation of hafnium silicate suppressed the crystallization of HfO{sub 2} at high temperatures. The dielectric constants increased from {approx}5 to {approx}17 as the hafnium content increased from 9 to 17 at. % in the hafnium silicate films. The leakage currents through the Hf-rich Hf-silicate films were two to three orders of magnitude lower than that of SiO{sub 2} with the same equivalent oxide thickness in the range of 1.6-2.3 nm. The estimated band gap of Hf-silicate films from the O 1s plasma loss spectra increased with the increasing Si content due to the higher band gap of SiO{sub 2} than that of HfO{sub 2}.

  19. Point defect energetics in the ZrNi and Zr2Ni intermetallics C.S. Moura a,b

    E-Print Network [OSTI]

    Motta, Arthur T.

    and Nuclear Engineering, The Pennsylvania State University, University Park, PA 16802, USA c Materials Science-neighbor Zr atoms. Ã? 2001 Elsevier Science B.V. All rights reserved. 1. Introduction There has been great of these compounds is governed by the balance between the irradiation damage and the annealing response

  20. Precipitation in cold-rolled Al–Sc–Zr and Al–Mn–Sc–Zr alloys prepared by powder metallurgy

    SciTech Connect (OSTI)

    Vlach, M., E-mail: martin.vlach@mff.cuni.cz [Charles University in Prague, Faculty of Mathematics and Physics, Ke Karlovu 3, CZ-121 16 Prague (Czech Republic); Stulikova, I.; Smola, B.; Kekule, T.; Kudrnova, H.; Danis, S. [Charles University in Prague, Faculty of Mathematics and Physics, Ke Karlovu 3, CZ-121 16 Prague (Czech Republic); Gemma, R. [King Abdullah University of Science and Technology (KAUST), Physical Sciences and Engineering Division, 23955-6900 Thuwal (Saudi Arabia); Ocenasek, V. [SVÚM a.s., Podnikatelská 565, CZ-190 11 Prague (Czech Republic); Malek, J. [Czech Technical University in Prague, Faculty of Mechanical Engineering, CZ-120 00 Prague (Czech Republic); Tanprayoon, D.; Neubert, V. [Institut für Materialprüfung und Werkstofftechnik, Freiberger Strasse 1, D-38678 Clausthal-Zellerfeld (Germany)

    2013-12-15T23:59:59.000Z

    The effects of cold-rolling on thermal, mechanical and electrical properties, microstructure and recrystallization behaviour of the AlScZr and AlMnScZr alloys prepared by powder metallurgy were studied. The powder was produced by atomising in argon with 1% oxygen and then consolidated by hot extrusion at 350 °C. The electrical resistometry and microhardness together with differential scanning calorimetry measurements were compared with microstructure development observed by transmission and scanning electron microscopy, X-ray diffraction and electron backscatter diffraction. Fine (sub)grain structure developed and fine coherent Al{sub 3}Sc and/or Al{sub 3}(Sc,Zr) particles precipitated during extrusion at 350 °C in the alloys studied. Additional precipitation of the Al{sub 3}Sc and/or Al{sub 3}(Sc,Zr) particles and/or their coarsening was slightly facilitated by the previous cold rolling. The presence of Sc,Zr-containing particles has a significant antirecrystallization effect that prevents recrystallization at temperatures minimally up to 420 °C. The precipitation of the Al{sub 6}Mn- and/or Al{sub 6}(Mn,Fe) particles of a size ? 1.0 ?m at subgrain boundaries has also an essential antirecrystallization effect and totally suppresses recrystallization during 32 h long annealing at 550 °C. The texture development of the alloys seems to be affected by high solid solution strengthening by Mn. The precipitation of the Mn-containing alloy is highly enhanced by a cold rolling. The apparent activation energy of the Al{sub 3}Sc particles formation and/or coarsening and that of the Al{sub 6}Mn and/or Al{sub 6}(Mn,Fe) particle precipitation in the powder and in the compacted alloys were determined. The cold deformation has no effect on the apparent activation energy values of the Al{sub 3}Sc-phase and the Al{sub 6}Mn-phase precipitation. - Highlights: • The Mn, Sc and Zr additions to Al totally suppresses recrystallization at 550 °C. • The Sc,Zr-containing particle precipitation is slightly facilitated by cold rolling. • The Mn-containing particle precipitation is highly enhanced by cold rolling. • Cold rolling has no effect on activation energy of the Al{sub 3}Sc and Al{sub 6}Mn precipitation. • The texture development is affected by high solid solution strengthening by Mn.

  1. Crystallization of Zr2PdxCu(1-x) and Zr2NixCu(1-x) Metallic Glass

    SciTech Connect (OSTI)

    Min Xu

    2008-08-18T23:59:59.000Z

    One interesting aspect of rretallic glasses is the numerous instances of the deviation of the phase selection from the amorphous state to thermodynamically stable phases during the crystallization process. Their devitrification pathways allow us to study the relationship between the original amorphous structure and their crystalline counter parts. Among the various factors of phase selections, size and electronic effects have been most extensively studied. Elucidating the phase selection process of a glassy alloy will be helpful to fill in the puzzle of the changes from disordered to ordered structures. In this thesis, Two model Zr{sub 2}Pd{sub x}Cu{sub (1-x)} and Zr{sub 2}Ni{sub x}Cu{sub (1-x)} (x = 0, 0.25, 0.5, 0.75 and 1) glassy systems were investigated since: (1) All of the samples can be made into a homogenous metallic glass; (2) The atomic radii differ from Pd to Cu is by 11%, while Ni has nearly the identical atomic size compare to Cu. Moreover, Pd and Ni differ by only one valence electron from Cu. Thus, these systems are ideal to test the idea of the effects of electronic structure and size factors; (3) The small number of components in these pseudo binary systems readily lend themselves to theoretical modeling. Using high temperature X-ray diffraction {HTXRD) and thermal analysis, topological, size, electronic, bond and chemical distribution factors on crystallization selections in Zr{sub 2}Pd{sub x}Cu{sub (1-x)} and Zr{sub 2}Ni{sub x}Cu{sub (1-x)} metallic glass have been explored. All Zr{sub 2}Pd{sub x}Cu{sub (1-x)} compositions share the same Cu11b phase with different pathways of meta-stable, icosahedral quasicrystalline phase (i-phase), and C16 phase formations. The quasicrystal phase formation is topologically related to the increasing icosahedral short range order (SRO) with Pd content in Zr{sub 2}Pd{sub x}Cu{sub (1·x)} system. Meta-stable C16 phase is competitive with C11b phase at x = 0.5, which is dominated by electronic structure rather than size effects. Cu-rich and Ni-rich compositions in Zr{sub 2}Ni{sub x}Cu{sub (1-x)} trend to divitrify to C11b or C16 phases respectively. In the proposed pseudo binary phase diagram, the domain of C16, C11b and co-existence phases are mainly related with the topology in the amorphous structure and formation enthalpies of crystalline phases.

  2. Band offsets in HfO{sub 2}/InGaZnO{sub 4} heterojunctions

    SciTech Connect (OSTI)

    Cho, Hyun [Department of Nanomechatronics Engineering, Pusan National University, Gyeongnam 627-706 (Korea, Republic of); Douglas, E. A.; Gila, B. P.; Craciun, V.; Lambers, E. S.; Pearton, S. J. [Department of Materials Science and Engineering, University of Florida, Gainesville, Florida 32611 (United States); Ren Fan [Department of Chemical Engineering, University of Florida, Gainesville, Florida 32611 (United States)

    2012-01-02T23:59:59.000Z

    The valence band discontinuity ({Delta}E{sub V}) of sputter deposited HfO{sub 2}/InZnGaO{sub 4} (IGZO) heterostructures was obtained from x-ray photoelectron spectroscopy measurements. The HfO{sub 2} exhibited a bandgap of 6.07 eV from absorption measurements. A value of {Delta}E{sub V} = 0.48 {+-} 0.025 eV was obtained by using the Ga 2p{sub 3/2}, Zn 2p{sub 3/2}, and In 3d{sub 5/2} energy levels as references. This implies a conduction band offset {Delta}E{sub C} of 2.39 eV in HfO{sub 2}/InGaZnO{sub 4} heterostructures and a nested interface band alignment.

  3. Ge doped HfO{sub 2} thin films investigated by x-ray absorption spectroscopy

    SciTech Connect (OSTI)

    Miotti, Leonardo; Bastos, Karen P.; Lucovsky, Gerald; Radtke, Claudio; Nordlund, Dennis [Department of Physics, North Carolina State University, Box 8202, Raleigh, North Carolina 27695-8202 (United States); Instituto de Quimica, Universidade Federal do Rio Grande do Sul, 91509-900 Porto Alegre (Brazil); Stanford Synchrotron Radiation Lightsource, Menlo Park, California 94025 (United States)

    2010-07-15T23:59:59.000Z

    The stability of the tetragonal phase of Ge doped HfO{sub 2} thin films on Si(100) was investigated. Hf(Ge)O{sub 2} films with Ge atomic concentrations varying from 0% to 15% were deposited by remote plasma chemical vapor deposition. The atomic structure on the oxide after rapid thermal annealing was investigated by x-ray absorption spectroscopy of the O and Ge K edges and by Rutherford backscattering spectrometry. The authors found that Ge concentrations as low as 5 at. % effectively stabilize the tetragonal phase of 5 nm thick Hf(Ge)O{sub 2} on Si and that higher concentrations are not stable to rapid thermal annealing at temperatures above 750 deg. C.

  4. On the K{sup {pi}} = 0{sup +} rotational bands in the {sup 178}Hf nucleus

    SciTech Connect (OSTI)

    Govor, L. I.; Demidov, A. M.; Kurkin, V. A., E-mail: kurkin@polyn.kiae.su; Mikhailov, I. V. [Russian Research Centre Kurchatov Institute (Russian Federation)

    2010-07-15T23:59:59.000Z

    The results obtained by studying the angular distributions of gamma rays with respect to the neutron-beam axis in the reaction {sup 178}Hf(n, n'{gamma}) involving the deexcitation of the K{sup {pi}} = 0{sup +} rotational bands of {sup 178}Hf are presented.New information about themultipole-mixing parameter {delta} in gamma transitions from the levels of these bands is obtained. The K{sup {pi}} = 0{sub 4}{sup +} band is constructed anew. The relationship between the parameter {delta} for the (2{sup +}0{sub n}-2{sup +}0{sub 1}) gamma transition and the energy gap {Delta}{sub n} = E{sub lev}(2{sup +}0{sub n}) - E{sub lev}(0{sup +}0{sub n}), on one hand, and the quasiparticle structure of the rotational band, on the other hand, is discussed for {sup 178}Hf on the basis of the quasiparticle-phonon model.

  5. Spatially-resolved EELS and EDS Analysis of HfOxNy Gate Dielectrics Deposited by MOCVD using [(C2H5)2N]4Hf with NO and O2

    E-Print Network [OSTI]

    Ng, Wai Tung

    -resolved electron energy loss spectroscopy (EELS) and energy-dispersive spectrometry (EDS). HfOxNy gate dielectrics a replacement for SiO2 as the gate dielectric material. HfO2 is a promising candidate due to its high dielectric constant its stability on Si. However, crystallization temperatures of less than 500 °C and high impurity

  6. Optical spectroscopic study of the SiN/HfO{sub 2} interfacial formation during rf sputtering of HfO{sub 2}

    SciTech Connect (OSTI)

    Toledano-Luque, M.; Lucia, M. L.; Prado, A. del; San Andres, E.; Martil, I.; Gonzalez-Diaz, G. [Departamento de Fisica Aplicada III, Universidad Complutense de Madrid, Ciudad Universitaria, E-28040 Madrid (Spain)

    2007-11-05T23:59:59.000Z

    High-k stacks formed by chemical-vapor-deposited SiN and high-pressure sputtered HfO{sub 2} in either O{sub 2} or Ar atmosphere have been studied. The introduction of a SiN layer is proposed to prevent the uncontrollable SiO{sub 2} growth while sputtering. The formation of Si-O bonds after the sputtering of the HfO{sub 2} film in O{sub 2} atmosphere was observed by infrared spectroscopy. Optical diagnosis of the plasma demonstrated a high density of O radicals in the system when working with O{sub 2}. The small radius and high reactivity of these O radicals are the source of the SiN oxidation. However, the structure of the SiN film is preserved during Ar sputtering.

  7. Two-step behavior of initial oxidation at HfO{sub 2}/Si interface

    SciTech Connect (OSTI)

    Miyata, Noriyuki [MIRAI, Advanced Semiconductor Research Center, National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki 305-8562 (Japan)

    2006-09-04T23:59:59.000Z

    In situ x-ray photoelectron spectroscopy revealed that initial Si oxidation at the HfO{sub 2}/Si(001) interface in O{sub 2} proceeds in a two-step manner with an initial slow stage followed by a fast one. This transition in the oxidation process is most likely caused by crystallization of the HfO{sub 2} film. The first stage at 400-600 deg. C exhibited postdeposition annealing conditions suitable for suppressing the interfacial Si oxide in a monolayer region.

  8. Triaxial strongly deformed bands in {sup 164}Hf and the effect of elevated yrast line

    SciTech Connect (OSTI)

    Ma Wenchao [Department of Physics, Mississippi State University, Mississippi State, MS 39762 (United States)

    2012-10-20T23:59:59.000Z

    Two exotic rotational bands have been identified in {sup 164}Hf and linked to known states. They are interpreted as being associated with the calculated triaxial strongly deformed (TSD) potential energy minimum. The bands are substantially stronger and are located at much lower spins than the previously discovered TSD bands in {sup 168}Hf. In addition to the proton and neutron shell gaps at large trixiality, it was proposed that the relative excitation energy of TSD bands above the yrast line plays an important role in the population of TSD bands.

  9. High-power ELF radiation generated by modulated HF heating of the ionosphere can cause Earthquakes, Cyclones and localized heating

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    High-power ELF radiation generated by modulated HF heating of the ionosphere can cause Earthquakes, the HAARP heater is the most powerful ionospheric heater, with 3.6GW of effective power using HF heating, Cyclones and localized heating Fran De Aquino Maranhao State University, Physics Department, S

  10. Trapping in deep defects under substrate hot electron stress in TiN/Hf-silicate based gate stacks

    E-Print Network [OSTI]

    Misra, Durgamadhab "Durga"

    Trapping in deep defects under substrate hot electron stress in TiN/Hf-silicate based gate stacks N. Zaslavsky Abstract Substrate hot electron stress was applied on n+ -ringed n-channel MOS capacitors with TiN/Hf-silicate. Introduction Hafnium silicate based high-j gate dielectrics have been put forth as the leading candidates

  11. Examination Report: OAS-RA-13-19 | Department of Energy

    Office of Environmental Management (EM)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary) " ,"ClickPipelinesProvedDecember 2005DepartmentDecember U.S. Department of9 Examination Report: OAS-RA-13-19

  12. Audit Special Report: OAS-RA-10-03 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious Rank EERE:Year in Review: Top Five EERE BlogAttachmentFlash2011-21 Audit Letter6-0136 AuditOAS-RA-10-03 Audit

  13. Audit Report: OAS-RA-11-08 | Department of Energy

    Energy Savers [EERE]

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious RankCombustionImprovement3--Logistical5/08 Attendance List1-02 Audit2-02 AuditRA-10-06 Audit2 Audit4

  14. Photoemission study of energy-band alignment for RuO{sub x}/HfO{sub 2}/Si system

    SciTech Connect (OSTI)

    Li, Q.; Wang, S.J.; Li, K.B.; Huan, A.C.H.; Chai, J.W.; Pan, J.S.; Ong, C.K. [Department of Physics, National University of Singapore, Singapore 117542 (Singapore); Institute of Materials Research and Engineering, 3 Research Link, Singapore 117602 (Singapore); Data Storage Institute, DSI Building, 5 Engineering Drive 1, Singapore 117608 (Singapore); Institute of Materials Research and Engineering, 3 Research Link, Singapore 117602, Singapore and Department of Physics, National University of Singapore, Singapore 117542 (Singapore); Institute of Materials Research and Engineering, 3 Research Link, Singapore 117602 (Singapore); Department of Physics, National University of Singapore, Singapore 117542 (Singapore)

    2004-12-20T23:59:59.000Z

    Conductive oxides RuO{sub x} as alternative electrode on high-{kappa} HfO{sub 2} gate dielectric have been fabricated by ultrahigh-vacuum sputtering and subsequently oxidized using oxygen plasma. The energy-band alignment for the RuO{sub x}/HfO{sub 2}/Si system and the oxidation-state dependence of barrier height for RuO{sub x} contacting to HfO{sub 2} dielectrics has been analyzed by x-ray photoemission spectroscopy. The valence- and conduction-band offsets of HfO{sub 2}/Si are determined to be 3.05{+-}0.1 and 1.48{+-}0.1 eV, respectively. The barrier heights for the RuO{sub x} contacting to HfO{sub 2} are oxidation-state dependent, in the range of 1.95-2.73 eV.

  15. Low-temperature method for enhancing sputter-deposited HfO{sub 2} films with complete oxidization

    SciTech Connect (OSTI)

    Tsai, C.-T.; Chang, T.-C.; Liu, P.-T.; Yang, P.-Y.; Kuo, Y.-C.; Kin, K.-T.; Chang, P.-L.; Huang, F.-S. [Institute of Electronics Engineering, National Tsing Hua University, HsinChu 300, Taiwan (China); Department of Physics and Institute of Electro-Optical Engineering, Center for Nanoscience and Nanotechnology, National Sun Yat-Sen University, 70 Lien-Hai Road, Kaohsiung 804, Taiwan (China); Department of Photonics and Display Institute, National Chiao Tung University, 1001 Ta-Hsueh Rd., HsinChu 300, Taiwan (China); Energy and Environment Research Laboratories, Industrial Technology Research Institute, Hsinchu 300, Taiwan (China); Institute of Electronics Engineering, National Tsing Hua University, HsinChu 300, Taiwan (China)

    2007-07-02T23:59:59.000Z

    A low-temperature method, supercritical CO{sub 2} fluid (SCF) technology, is proposed to improve the dielectric properties of ultrathin hafnium oxide (HfO{sub 2}) film at 150 deg. C without significant formation of parasitic oxide at the interface between HfO{sub 2} and Si substrate. In this research, the HfO{sub 2} films were deposited by dc sputter at room temperature and post-treated by SCF which is mixed with 5 vol % propyl alcohol and 5 vol % H{sub 2}O. From high-resolution transmission electron microscopy image, the interfacial oxide of SCF-treated HfO{sub 2} film is only 5 A ring thick. Additionally, the enhancements in the qualities of sputter-deposited HfO{sub 2} film after SCF process are exhibited by x-ray photoelectron spectroscopy and capacitance-voltage (C-V) measurement.

  16. Meridian-scanning photometer, coherent HF radar, and magnetometer observations of the cusp: a case study

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    the transport of mass, energy, and momentum from the solar wind into the near-Earth environment, is facilitated with the CUTLASS Finland coherent HF radar, a meridian-scanning photometer located at Ny AÃ? lesund, Svalbard on the scale of minutes, and which are believed to be related to the dynamic nature of energy and momentum

  17. Metal-gate-induced reduction of the interfacial layer in Hf oxide gate stacks

    SciTech Connect (OSTI)

    Goncharova, L. V.; Dalponte, M.; Gustafsson, T.; Celik, O.; Garfunkel, E.; Lysaght, P. S.; Bersuker, G. [Department of Physics and Astronomy, and Laboratory for Surface Modification, Rutgers University, 136 Frelinghuysen Rd., Piscataway, New Jersey 08854 (United States); Department of Chemistry and Chemical Biology, and Laboratory for Surface Modification, Rutgers University, 610 Taylor Rd., Piscataway, New Jersey 08854 (United States); SEMATECH, 2705 Montopolis Dr., Austin, Texas 78741 (United States)

    2007-03-15T23:59:59.000Z

    The properties of high-{kappa} metal oxide gate stacks are often determined in the final processing steps following dielectric deposition. We report here results from medium energy ion scattering and x-ray photoelectron spectroscopy studies of oxygen and silicon diffusion and interfacial layer reactions in multilayer gate stacks. Our results show that Ti metallization of HfO{sub 2}/SiO{sub 2}/Si stacks reduces the SiO{sub 2} interlayer and (to a more limited extent) the HfO{sub 2} layer. We find that Si atoms initially present in the interfacial SiO{sub 2} layer incorporate into the bottom of the high-{kappa} layer. Some evidence for Ti-Si interdiffusion through the high-{kappa} film in the presence of a Ti gate in the crystalline HfO{sub 2} films is also reported. This diffusion is likely to be related to defects in crystalline HfO{sub 2} films, such as grain boundaries. High-resolution transmission electron microscopy and corresponding electron energy loss spectroscopy scans show aggressive Ti-Si intermixing and oxygen diffusion to the outermost Ti layer, given high enough annealing temperature. Thermodynamic calculations show that the driving forces exist for some of the observed diffusion processes.

  18. Scanning tunneling microscopy study of nitrogen incorporated HfO{sub 2}

    SciTech Connect (OSTI)

    Ong, Y. C.; Ang, D. S.; Pey, K. L.; Li, X. [Nanyang Technological University, School of Electrical and Electronic Engineering, Nanyang Avenue, Singapore 639798 (Singapore); O'Shea, S. J.; Wang, S. J. [Institute of Materials Research and Engineering, A-STAR - Agency for Science, Technology and Research, 3 Research Link, Singapore 11760 (Singapore); Tung, C. H. [Institute of Microelectronics, A-STAR - Agency for Science, Technology and Research, 11 Science Park Road, Singapore Science Park II, Singapore 117685 (Singapore)

    2008-09-15T23:59:59.000Z

    The impact of nitrogen incorporation on the physical and electrical characteristics of the HfO{sub 2} is examined. X-ray photoelectron spectroscopy shows that nitrogen can be incorporated into the HfO{sub 2} via a two-step thermal anneal--first in ultrahigh vacuum (UHV) and subsequently in N{sub 2}. Following the N{sub 2} anneal, scanning tunneling microscopy in UHV reveals a marked reduction in the low-voltage leakage current under gate injection biasing. From band theory and existing first-principles simulation results, one may consistently attribute this improvement to the passivation of oxygen vacancies in the HfO{sub 2} by nitrogen. Improvement in the breakdown strength of the HfO{sub 2} subjected to ramp-voltage stress (substrate injection) is also observed after the N{sub 2} anneal. The local current-voltage curves acquired concurrently during the ramp-voltage stress exhibit 'space-charge limited conduction', which implies that the observed improvement in breakdown strength may be related to a limitation of the current flow through the gate stack in the high stress voltage regime.

  19. Investigation of HF plasma turbulence excitation and dissipation in the vicinity of 5th

    E-Print Network [OSTI]

    of stimulated electromagnetic emission (SEE) of the ionosphere pumped by powerful HF radio waves are presented, Uppsala Division, SE-751 21 Uppsala, Sweden Experimental results on development and relaxation times after PW turn off d 0.7­1.0 ms are 2­4 times faster than collisional ones for the Langmuir waves

  20. Oxygen diffusion and reactions in Hf-based dielectrics L. V. Goncharova,a

    E-Print Network [OSTI]

    Gustafsson, Torgny

    Oxygen diffusion and reactions in Hf-based dielectrics L. V. Goncharova,a M. Dalponte, D. G Oxygen transport in and reactions with thin hafnium oxide and hafnium silicate films have been. The exchange rate is faster for pure hafnium oxides than for silicates. The amount of exchanged oxygen

  1. HF radar in French Mediterranean Sea: an element of MOOSE Mediterranean Ocean Observing System on Environment

    E-Print Network [OSTI]

    Boyer, Edmond

    Sea in the context of climate change and anthropogenic pressure and to supply and maintain longHF radar in French Mediterranean Sea: an element of MOOSE Mediterranean Ocean Observing System , Pascal Guterman2 , Karim Bernardet2 1 Mediterranean Institute of Oceanography (MIO, UM 110, USTV

  2. Elevated temperature ablation resistance of HfC particle-reinforced tungsten composites

    E-Print Network [OSTI]

    Hong, Soon Hyung

    C­W was attributed to the low thermal conductivity, high oxidation resistance, and high melting point of the Hf melting points (e.g., 3440 °C for W), high moduli of elasticity, good thermal shock resistances, and good torch was used to ablate the samples at high temperature. Ablation resistance improved with an in

  3. Control of silicidation in HfO2/Si,,100... interfaces Deok-Yong Cho, Kee-Shik Park, B.-H. Choi,a

    E-Print Network [OSTI]

    Oh, Se-Jung

    like nitrogen.6,7 Among these, Hf-silicide is probably most detrimental since it is metallic and degrades the capacitor performance. Metal- lic Hf-silicide formation has been reported in the interfaceControl of silicidation in HfO2/Si,,100... interfaces Deok-Yong Cho, Kee-Shik Park, B.-H. Choi

  4. Identification of phases in the interaction layer between U-Mo-Zr/Al and U-Mo-Zr/Al-Si

    SciTech Connect (OSTI)

    Varela, C.L. Komar; Arico, S.F.; Mirandou, M.; Balart, S.N. [Departamento Materiales, GIDAT, GAEN, CNEA, Avda. Gral Paz 1499, B1650KNA, San Martin (Argentina); Gribaudo, L.M. [Departamento Materiales, GIDAT, GAEN, CNEA, Avda. Gral Paz 1499, B1650KNA, San Martin (Argentina); CONICET, Avda. Rivadavia 1917, C1033AAJ, Buenos Aires (Argentina)

    2008-07-15T23:59:59.000Z

    Out-of-pile diffusion experiments were performed between U-7wt.% Mo-1wt.% Zr and Al or Al A356 (7,1wt.% Si) at 550 deg. C. In this work morphological characterization and phase identification on both interaction layer are presented. They were carried out by the use of different techniques: optical and scanning electron microscopy, X-Ray diffraction and WDS microanalysis. In the interaction layer U-7wt.% Mo-1wt.% Zr/Al, the phases UAl{sub 3}, UAl{sub 4}, Al{sub 20}Mo{sub 2}U and Al{sub 43}Mo{sub 4}U{sub 6} were identified. In the interaction layer U-7wt.% Mo-1wt.% Zr/Al A356, the phases U(Al, Si) with 25at.% Si and Si{sub 5}U{sub 3} were identified. This last phase, with a higher Si concentration, was identified with XRD Synchrotron radiation performed at the National Synchrotron Light Laboratory (LNLS), Campinas, Brasil. (author)

  5. Crystallization and glass formation in electron and laser beam irradiated Cu-Zr alloys

    SciTech Connect (OSTI)

    Huang, J.S.; Kaufmann, E.N.; Wall, M.A.; Olsen, B.L.

    1987-11-01T23:59:59.000Z

    Four Cu-Zr alloys, Cu/sub 56/Zr/sub 44/, Cu/sub 50/Zr/sub 50/, Cu/sub 47/Zr/sub 53/, and Cu/sub 33/Zr/sub 67/, were surface melted with electron and pulsed laser beams to compare their kinetics of nucleation, growth and glass formation. It was observed that the ease of glass formation increased in the order: Cu/sub 33/Zr/sub 67/, Cu/sub 47/Zr/sub 53/, Cu/sub 56/Zr/sub 44/, and Cu/sub 50/Zr/sub 50/. The nucleation and regrowth produced different metastable phases. At the equiatomic composition, the preferred phase is a CsCl-type (B2) BCC structure. As the composition deviates from this, the preferred phase is either orthorhombic or tetragonal with a much larger unit cell not previously reported in the literature. The maximum growth velocity of these metastable phases was found to be about 0.025 m/s. The slow kinetics are responsible for the ease of glass formation in these systems. 4 refs., 7 figs., 2 tabs.

  6. E-Print Network 3.0 - application zr-sn alloys Sample Search...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    used... , Zr, Sn, ... Source: Zheng, Yufeng - Department of Advanced Materials and Nanotechnology, Peking University Collection: Materials Science ; Biology and Medicine 2...

  7. Nitrogen Doping and Thermal Stability in HfSiOxNy Studied by Photoemission and X-ray Absorption Spectroscopy

    SciTech Connect (OSTI)

    Toyoda, Satoshi; Okabayashi, Jun; Takahashi, Haruhiko; Oshima, Masaharu; /Tokyo U.; Lee, Dong-Ick; Sun, Shiyu; sun, Steven; Pianetta, Piero A.; /SLAC, SSRL; Ando, Takashi; Fukuda, Seiichi; /SONY, Atsugi

    2005-12-14T23:59:59.000Z

    We have investigated nitrogen-doping effects into HfSiO{sub x} films on Si and their thermal stability using synchrotron-radiation photoemission and x-ray absorption spectroscopy. N 1s core-level photoemission and N K-edge absorption spectra have revealed that chemical-bonding states of N-Si{sub 3-x}O{sub x} and interstitial N{sub 2}-gas-like features are clearly observed in as-grown HfSiO{sub x}N{sub y} film and they decrease upon ultrahigh vacuum (UHV) annealing due to a thermal instability, which can be related to the device performance. Annealing-temperature dependence in Hf 4f and Si 2p photoemission spectra suggests that the Hf-silicidation temperature is effectively increased by nitrogen doping into the HfSiO{sub x} although the interfacial SiO{sub 2} layer is selectively reduced. No change in valence-band spectra upon UHV annealing suggests that crystallization of the HfSiO{sub x}N{sub y} films is also hindered by nitrogen doping into the HfSiO{sub x}.

  8. Interfacial reaction induced phase separation in La{sub x}Hf{sub y}O films

    SciTech Connect (OSTI)

    Ma, J. W.; Lee, W. J.; Cho, M.-H. [Institute of Physics and Applied Physics, Yonsei University, Seoul 120-749 (Korea, Republic of); Lee, K. M.; Sohn, H. C. [Department of Material Science and Engineering, Yonsei University, Seoul 120-749 (Korea, Republic of); Kim, C. S. [Korea Research Institute of Standards and Science, Daejeon 305-540 (Korea, Republic of); Cho, H. J. [Process Development Team, Semiconductor R and D Center, Samsung Electronics Co., LTD, Gyeonggi-Do 449-711 (Korea, Republic of)

    2011-06-15T23:59:59.000Z

    Amorphous La{sub x}Hf{sub y}O films containing La at concentrations (x) of 50 and 20% were prepared by atomic layer deposition on ultrathin SiO{sub 2} films (1 nm). We examined the electronic structures and microstructures of the La{sub x}Hf{sub y}O films by x-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), energy dispersive x-ray spectroscopy (EDS), and x-ray diffraction (XRD). Phase separation into La{sub 2}O{sub 3} and HfO{sub 2} was observed in the La{sub x}Hf{sub y}O films subjected to annealing temperatures over 900 deg. C, although the mixture of La{sub 2}O{sub 3} and HfO{sub 2} is thermodynamically stable. The structural changes that occurred as the result of phase separation were dependent on the concentrations of La and Hf in the films. During the annealing treatment, silicate was produced due to interfacial reactions and the interfacial reactions were found to be dependent on the La{sub 2}O{sub 3} content in the La{sub x}Hf{sub y}O films, which has a significant influence on the phase separation process and resulting film structure.

  9. A low temperature fabrication of HfO{sub 2} films with supercritical CO{sub 2} fluid treatment

    SciTech Connect (OSTI)

    Tsai, C.-T.; Huang, F.-S. [Institute of Electronics Engineering, National Tsing Hua University, HsinChu 300, Taiwan (China); Chang, T.-C. [Department of Physics, Center for Nanoscience and Nanotechnology, National Sun Yat-set University, 70 Lien-hai Road, Kaohsiung 804, Taiwan (China); Institute of Electro-Optical Engineering, National Sun Yat-sen University, Kaohsiung 804, Taiwan (China); Kin, K.-T. [Industrial Technology Research Institute-Energy and Environment Research Laboratories, Hsinchu 300, Taiwan (China); Liu, P.-T.; Yang, P.-Y. [Department of Photonics and Display Institute, National Chiao Tung University, Hsinchu 300, Taiwan (China); Weng, C.-F. [Department of Physics, Center for Nanoscience and Nanotechnology, National Sun Yat-set University, 70 Lien-hai Road, Kaohsiung 804, Taiwan (China)

    2008-04-01T23:59:59.000Z

    To improve the dielectric properties of sputter-deposited hafnium oxide (HfO{sub 2}) films, the supercritical CO{sub 2} (SCCO{sub 2}) fluid technology is introduced as a low temperature treatment. The ultrathin HfO{sub 2} films were deposited on p-type (100) silicon wafer by dc sputtering at room temperature and subsequently treated with SCCO{sub 2} fluids at 150 deg. C to diminish the traps in the HfO{sub 2} films. After SCCO{sub 2} treatment, the interfacial parasitic oxide between the Si substrate and HfO{sub 2} layer is only about 5 A, and the oxygen content of the HfO{sub 2} films apparently increased. From current-voltage (I-V) and capacitance-voltage (C-V) measurements, the leakage current density of the SCCO{sub 2}-treated HfO{sub 2} films is repressed from 10{sup -2} to 10{sup -7} A/cm{sup 2} at electric field=3 MV/cm due to the reduction of traps in the HfO{sub 2} films. The equivalent oxide thickness also obviously decreased. Besides, the efficiency of terminating traps is relative to the pressure of the SCCO{sub 2} fluids.

  10. Report on Characterization of U-10 wt.% Zr Alloy

    SciTech Connect (OSTI)

    McKeown, J; Wall, M; Hsiung, L; Turchi, P

    2012-03-01T23:59:59.000Z

    This report summarizes the chemical and structural characterization results for a U-10 wt.% Zr alloy to be used in an ultra-high burn-up nuclear fuel concept. The as-cast alloy material was received from Texas A and M University. Characterization and an initial heat treatment of the alloy material were conducted at Lawrence Livermore National Laboratory. The as-received ingot was sectioned for X-ray analysis, metallography, SEM, TEM, and heat treatments, as shown in Figure 1.

  11. Isoscalar Breathing Mode State in Zr-90 and Sn-116

    E-Print Network [OSTI]

    Rozsa, C. M.; Youngblood, David H.; Bronson, J. D.; Lui, YW; Garg, U.

    1980-01-01T23:59:59.000Z

    PHYSICAL RKVIK% C VOLUIHE 21, NUMBER 4 Isoscalar breathing mode state in Zr and "Sn C. M. Rozsa, D. H. Youngblood, J. D. Bronson, Y.-%. Lui, and U. Garg Cyclotron Institute, Texas AckM University, College Station, Texas 77843 (Received 5..., BRONSON, LUI, AND GARG larger opening and served to catch some particles scattered from the first set. For measurements at 0', the beam was passed into the spectrograph and one set of brass defining slits with an open- ing of 6.4' horizontally by 3.V...

  12. Site preferences of indium impurity atoms in intermetallics having Al3Ti and Al3Zr crystal structures

    E-Print Network [OSTI]

    Collins, Gary S.

    Site preferences of indium impurity atoms in intermetallics having Al3Ti and Al3Zr crystal-04843 (Metals Program) and Praveen Sinha Fund for Physics Research. L12 DO22 DO23 Cu3Au Al3Ti Al3Zr #12;Outline · Indium was doped in samples of Al3V and Al3Ti (Al3Ti structure) and Al3Zr (Al3Zr structure) by arc

  13. Atomistic Studies of Cation Transport in Tetragonal ZrO2 During Zirconium Corrosion

    SciTech Connect (OSTI)

    Xian-Ming Bai; Yongfeng Zhang; Michael R. Tonks

    2013-10-01T23:59:59.000Z

    Zirconium alloys are the major fuel cladding materials in current reactors. The water-side corrosion is one of the major degradation mechanisms of these alloys. During corrosion the transport of oxidizing species in zirconium dioxide (ZrO2) determines the corrosion kinetics. Previously it has been argued that the outward diffusion of cation ions is important for forming protective oxides. In this work, the migration of Zr defects in tetragonal ZrO2 is studied with temperature accelerated dynamics and molecular dynamics simulations. The results show that Zr interstitials have anisotropic diffusion and migrate preferentially along the [001] or c direction in tetragonal ZrO2. The compressive stresses can increase the Zr interstitial migration barrier significantly. The migration barriers of some defect clusters can be much lower than those of point defects. The migration of Zr interstitials at some special grain boundaries is much slower than in a bulk oxide. The implications of these atomistic simulation results in the Zr corrosion are discussed.

  14. Transformation plasticity and thermoelastic behavior in ZrO2-containing ceramics

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    565 Transformation plasticity and thermoelastic behavior in ZrO2-containing ceramics A. H. Heuer plasticité de transformation dans ZrO2, qui est responsable de la ré- sistance mécanique et de la grande profit. Dans certaines conditions, cette transformation est réversible, autocatalytique et

  15. Electronic properties of InP (001)/HfO{sub 2} (001) interface: Band offsets and oxygen dependence

    SciTech Connect (OSTI)

    KC, Santosh; Dong, Hong; Longo, Roberto C.; Xiong, Ka [Department of Materials Science and Engineering, The University of Texas at Dallas, Richardson, Texas 75080 (United States); Wang, Weichao [Department of Electronics and Microelectronics and Tianjin Key Laboratory of Photo-Electronic Thin Film Device and Technology, Nankai University, Tianjin 300071 (China); Wallace, Robert M.; Cho, Kyeongjae, E-mail: kjcho@utdallas.edu [Department of Materials Science and Engineering, The University of Texas at Dallas, Richardson, Texas 75080 (United States); Department of Physics, The University of Texas at Dallas, Richardson, Texas 75080 (United States)

    2014-01-14T23:59:59.000Z

    Using ab-initio methods, atomic structures and electronic properties of InP (001)/HfO{sub 2} (001) interface are studied within the framework of density functional theory. We examine the InP/HfO{sub 2} model interface electronic structures under varying oxidation conditions. The effects of indium and phosphorous concentrations on interfacial bonding, defect states, band offsets, and the thermodynamic stability at the interface are also investigated. The origin of interfacial gap states in InP (001)/HfO{sub 2} (001) interface are proposed, mainly from the P-rich oxides, which is validated by our experimental work. This highlights the importance of surface passivation prior to high-? deposition based on the in situ spectroscopic results of atomic layer deposition of HfO{sub 2} on InP.

  16. Initial phases in sputter deposited HfO{sub 2}-Al{sub 2}O{sub 3} nanolaminate films

    SciTech Connect (OSTI)

    Hoppe, E. E.; Aita, C. R.; Gajdardziska-Josifovska, M. [Advanced Coatings Experimental Laboratory, University of Wisconsin-Milwaukee, P.O. Box 784, Milwaukee, Wisconsin 53201 (United States); Department of Physics and Laboratory for Surface Studies, University of Wisconsin-Milwaukee, P.O. Box 413, Milwaukee, Wisconsin 53201 (United States)

    2007-11-12T23:59:59.000Z

    Nanolaminate films of crystalline HfO{sub 2} and amorphous Al{sub 2}O{sub 3} were grown by reactive sputter deposition on unheated fused SiO{sub 2} and the surface oxide of <111> Si. X-ray diffraction showed the amount of monoclinic (m) HfO{sub 2} decreased with decreasing HfO{sub 2} layer thickness, consistent with a finite crystal size effect. High resolution transmission electron microscopy of individual crystallites detected tetragonal (t) and orthorhombic (o) HfO{sub 2} as the initial phases formed. Whereas the t{yields}m transition is accomplished by a shear mechanism, we demonstrate the important role of polysynthetic twinning for the o{yields}m transition.

  17. Enhanced electrical characteristics of Au nanoparticles embedded in high-k HfO{sub 2} matrix

    SciTech Connect (OSTI)

    Yang, Jung Yup; Kim, Ju Hyung; Choi, Won Joon; Do, Young Ho; Kim, Chae Ok; Hong, Jin Pyo [New Functional Materials and Devices Laboratory, Department of Physics, Hanyang University, Seoul 133-791 (Korea, Republic of)

    2006-09-15T23:59:59.000Z

    We present experimental results for laser-induced Au nanoparticle (NP) embedded in a HfO{sub 2} high-k dielectric matrix. Cross-sectional transmission electron microscopy images showed that the Au NPs of 8 nm in diameter were clearly embedded in HfO{sub 2} matrix. Capacitance-voltage measurements of Pt/HfO{sub 2}/Au NPs/HfO{sub 2} on p-type Si substrate reliably exhibited metal-oxide-semiconductor behavior with a large flatband shift of 4.7 V. In addition, the charge retention time at room temperature was found to exceed 10{sup 5} h. This longer time was attributed to the higher electron barrier height via high work function of the Au NP.

  18. Shape memory response and microstructural evolution of a severe plastically deformed high temperature shape memory alloy (NiTiHf)

    E-Print Network [OSTI]

    Simon, Anish Abraham

    2006-04-12T23:59:59.000Z

    NiTiHf alloys have attracted considerable attention as potential high temperature Shape Memory Alloy (SMA) but the instability in transformation temperatures and significant irrecoverable strain during thermal cycling under constant stress remains a...

  19. EFFECT OF AGING ON THE PHASE TRANSFORMATION AND MECHANICAL BEHAVIOR OF Ti36Ni49Hf15 HIGH

    E-Print Network [OSTI]

    Zheng, Yufeng

    and Engineering, Harbin Institute of Technology, Harbin 150001, People's Republic of China (Received August 19 the microstructure, transformation temperature, mechanical properties and shape memory effects (SMEs) for Ti36Ni49Hf

  20. Human Factors Process Failure Mode and Effects Analysis (HF PFMEA) Application in the Evaluation of Management Risks

    E-Print Network [OSTI]

    Soguilon, Nenita M.

    2009-12-18T23:59:59.000Z

    .3.1. Mechanisms of Prevention ............................................................................................... 11 2.4. Human Factors Process Failure Mode and Effects Analysis (HF PFMEA) ....................... 11 2.5. FMEA Components... ........................................................................................... 15 2.5.5. Risk Priority Number ....................................................................................................... 17 2.6. FMEA Model...

  1. Mode specificity in the HF + OH ? F + H{sub 2}O reaction

    SciTech Connect (OSTI)

    Song, Hongwei; Li, Jun; Guo, Hua, E-mail: hguo@unm.edu [Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131 (United States)

    2014-10-28T23:59:59.000Z

    Full-dimensional quantum dynamics and quasi-classical trajectory calculations are reported for the title reaction on a recently constructed ab initio based global potential energy surface. Strong mode specificity was found, consistent with the prediction of the sudden vector projection model. Specifically, the HF vibration strongly promotes the reaction while the OH vibration has little effect. Rotational excitations of both reactants slightly enhance the reaction.

  2. Reactive ion beam etching of HfO{sub 2} film and removal of sidewall redeposition

    SciTech Connect (OSTI)

    Wang Xudi; Liu Ying; Xu Xiangdong; Fu Shaojun; Cui Zheng [National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230026 (China) and School of Mechanical and Automobile Engineering, Hefei University of Technology, Hefei 230009 (China); National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230026 (China); Central Microstructure Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxon OX11 0QX (United Kingdom)

    2006-07-15T23:59:59.000Z

    Comparative studies on ion beam etching (IBE) and reactive ion beam etching (RIBE) of HfO{sub 2} film have been carried out using photoresist as the masking layer. The etching rates of HfO{sub 2} film and photoresist mask in pure Ar and Ar/CHF{sub 3} mixture plasmas were measured as a function of ion energy, plasma composition, and ion beam incident angle. It has been found that the RIBE with Ar/CHF{sub 3} plasma is capable of lowering the threshold energy of ion beam and increasing sputtering yield, compared to the IBE with pure Ar. The redeposition of photoresist sidewall is a major issue, due to the formation of nonvolatile etching products during sputtering of HfO{sub 2} film in both IBE and RIBE. However, the sidewall redeposition can be easily removed in HCl solutions with assistance of ultrasonic wave for RIBE with Ar/CHF{sub 3} plasma. Alternatively, the sidewall redeposition can be eliminated by controlling the slope of photoresist sidewall or combined with ion incident angle.

  3. Gate Metal-Induced Diffusion and Interface Reactions in Hf Oxide Films on Si

    SciTech Connect (OSTI)

    Goncharova, Lyudmila V.; Dalponte, Mateus; Celik, Ozgur; Garfunkel, Eric; Gustafsson, Torgny [Departments of Physics and Chemistry, and Laboratory for Surface Modification, Rutgers University, Piscataway, NJ 08854 (United States); Lysaght, Pat S.; Bersuker, Gennadi I. [Sematech, Austin, Texas 78741 (United States)

    2007-09-26T23:59:59.000Z

    When metal electrodes are deposited on a high-{kappa} metal-oxide/SiO{sub 2}/Si stack, chemical interactions may occur both at the metal/high-{kappa} and the high-{kappa}/Si interfaces, causing changes in electrical performance. We report here results from medium energy ion scattering (MEIS) and x-ray photoelectron (XPS) studies of oxygen and silicon transport and interfacial layer reactions in multilayer gate stacks. Our results show that Ti deposition on HfO{sub 2}/SiO{sub 2}/Si stacks causes reduction of the SiO{sub 2} interfacial layer and (to a lesser extent) the HfO{sub 2} layer. Silicon atoms initially present in the interfacial SiO{sub 2} layer incorporate into the bottom of the high-{kappa} layer. Some evidence for titanium-silicon interdiffusion through the high-{kappa} film in the presence of a titanium gate in crystalline HfO{sub 2} films is also reported.

  4. Impact of titanium addition on film characteristics of HfO{sub 2} gate dielectrics deposited by atomic layer deposition

    SciTech Connect (OSTI)

    Triyoso, D.H.; Hegde, R.I.; Zollner, S.; Ramon, M.E.; Kalpat, S.; Gregory, R.; Wang, X.-D.; Jiang, J.; Raymond, M.; Rai, R.; Werho, D.; Roan, D.; White, B.E. Jr.; Tobin, P.J. [Freescale Semiconductor, Inc., Advanced Products Research and Development Laboratory, 3501 Ed Bluestein Boulevard, Austin, Texas 78721 (United States)

    2005-09-01T23:59:59.000Z

    The impact of 8-to 45-at. % Ti on physical and electrical characteristics of atomic-layer-deposited and annealed hafnium dioxide was studied using vacuum-ultraviolet spectroscopic ellipsometry, secondary ion mass spectroscopy, transmission electron microscopy, atomic force microscopy, x-ray diffraction, Rutherford backscattering spectroscopy, x-ray photoelectron spectroscopy, and x-ray reflectometry. The role of Ti addition on the electrical performance is investigated using molybdenum (Mo)-gated capacitors. The film density decreases with increasing Ti addition. Ti addition stabilizes the amorphous phase of HfO{sub 2}, resulting in amorphous films as deposited. After a high-temperature annealing, the films transition from an amorphous to a polycrystalline phase. Orthorhombic Hf-Ti-O peaks are detected in polycrystalline films containing 33-at. % or higher Ti content. As Ti content is decreased, monoclinic HfO{sub 2} becomes the predominant microstructure. No TiSi is formed at the dielectric/Si interface, indicating films with good thermal stability. The band gap of Hf-Ti-O was found to be lower than that of HfO{sub 2}. Well-behaved capacitance-voltage and leakage current density-voltage characteristics were obtained for Hf-Ti-O. However, an increased leakage current density was observed with Ti addition. The data from capacitance-voltage stressing indicate a smaller flatband voltage (V{sub fb}) shift in the HfO{sub 2} films with low Ti content when compared with the HfO{sub 2} films. This indicates less charge trapping with a small amount of Ti addition.

  5. Chemical analysis of HfO{sub 2}/Si (100) film systems exposed to NH{sub 3} thermal processing

    SciTech Connect (OSTI)

    Lysaght, Patrick S.; Barnett, Joel; Bersuker, Gennadi I.; Woicik, Joseph C.; Fischer, Daniel A.; Foran, Brendan; Tseng, Hsing-Huang; Jammy, Raj [Front End Process Division, SEMATECH, 2706 Montopolis Drive, Austin, Texas 78741-6499 (United States); National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); Physical Characterization Laboratory, Advanced Technology Development Facility, 2706 Montopolis Drive, Austin, Texas 78741-6499 (United States); Front End Process Division, SEMATECH, 2706 Montopolis Drive, Austin, Texas 78741-6499 (United States)

    2007-01-15T23:59:59.000Z

    Nitrogen incorporation in HfO{sub 2}/SiO{sub 2} films utilized as high-k gate dielectric layers in advanced metal-oxide-semiconductor field effect transistors has been investigated. Thin HfO{sub 2} blanket films deposited by atomic layer deposition on either SiO{sub 2} or NH{sub 3} treated Si (100) substrates have been subjected to NH{sub 3} and N{sub 2} anneal processing. Several high resolution techniques including electron microscopy with electron energy loss spectra, grazing incidence x-ray diffraction, and synchrotron x-ray photoelectron spectroscopy have been utilized to elucidate chemical composition and crystalline structure differences between samples annealed in NH{sub 3} and N{sub 2} ambients as a function of temperature. Depth profiling of core level binding energy spectra has been obtained by using variable kinetic energy x-ray photoelectron spectroscopy with tunable photon energy. An 'interface effect' characterized by a shift of the Si{sup 4+} feature to lower binding energy at the HfO{sub 2}/SiO{sub 2} interface has been detected in the Si 1s spectra; however, no corresponding chemical state change has been observed in the Hf 4f spectra acquired over a broad range of electron take-off angles and surface sensitivities. The Si 2p spectra indicate Si-N bond formation beneath the HfO{sub 2} layer in the samples exposed to NH{sub 3} anneal. The NH{sub 3} anneal ambient is shown to produce a metastable Hf-N bond component corresponding to temperature driven dissociation kinetics. These findings are consistent with elemental profiles across the HfO{sub 2}/Si(100) interface determined by electron energy loss spectroscopy measurements. X-ray diffraction measurements on similarly treated films identify the structural changes resulting from N incorporation into the HfO{sub 2} films.

  6. NIH eRA System xTrain External Termination of Fellowships Quick Reference 1 January 27, 2011

    E-Print Network [OSTI]

    Baker, Chris I.

    NIH eRA System xTrain External Termination of Fellowships Quick Reference 1 January 27, 2011 Powering the Advancement of Science xTrain Termination of Fellowships Quick Reference Guide for Institution finds the Fellowship award to be terminated and selects the View Trainee Roster link. NOTE: Although

  7. NIH eRA System xTrain Termination for Appointments Quick Reference 1 January 27, 2011

    E-Print Network [OSTI]

    Baker, Chris I.

    NIH eRA System xTrain Termination for Appointments Quick Reference 1 January 27, 2011 Powering the Advancement of Science xTrain Termination of Appointments Quick Reference Guide for Institution Users 1. The PD/PI Initiates a Termination Notice (TN) · The PD/PI locates the Trainee on the Trainee Roster

  8. An experimental and numerical study of surface tension-driven melt flow R.A. Parsons a,, F. Nimmo a

    E-Print Network [OSTI]

    Nimmo, Francis

    An experimental and numerical study of surface tension-driven melt flow R.A. Parsons a,, F. Nimmo 2007 Abstract To determine the role of surface tension-driven melt migration in planetary bodies, we, surface tension causes the melt to relax back to a homogeneous distribution. Samples composed of 76 vol

  9. 1997 BNL Site Environmental Report E -1 Bari, R.A., Gordon, D., Moran, D., and Volkow, N.,

    E-Print Network [OSTI]

    APPENDIX E 1997 BNL Site Environmental Report E - 1 Bari, R.A., Gordon, D., Moran, D., and Volkow, N., 1997. Report of the Ad Hoc Committee on Environmental, Safety, and Health Decision Making at Brookhaven National Laboratory (April 29, 1997). Brookhaven National Laboratory, 1997. Environmental

  10. NIH Grants.gov and eRA Commons flowchart Electronic Application Process PreparationofApplicationSubmissiontoNIHApplicantRegistration

    E-Print Network [OSTI]

    NIH Grants.gov and eRA Commons flowchart ­ Electronic Application Process Preparationof by the RO for Grant.gov, PI will be set up by the RO in eraCommons; AO (cannot submit to NIH) = Senior Research Administrator/Research Services Manager; SO (submit to NIH) = Research Services/ Grants Manager

  11. Microfluidics for block polymer shells (DMR 0819860) SEED :H.A. Stone, R.A. Register and Janine Nunes

    E-Print Network [OSTI]

    Petta, Jason

    Microfluidics for block polymer shells (DMR 0819860) SEED :H.A. Stone, R.A. Register and Janine. We utilized microfluidic methods to investigate the role of geometric structures, e.g. thin spherical, microfluidic devices with two consecutive flow-focusing junctions were used to generate air bubble

  12. 25. Bialecki RA, Ostrowski ZP, Kassab AJ, Yin Q, Sciubba E (2002) Coupling FEM, BEM, and analyti-

    E-Print Network [OSTI]

    Qin, Qinghua

    (such as iron) form permanent magnets or are attracted to magnets. An everyday example of ferromagnetism25. Bialecki RA, Ostrowski ZP, Kassab AJ, Yin Q, Sciubba E (2002) Coupling FEM, BEM, and analyti, a ferrimagnetic mate- rial is one in which the magnetic moments of the atoms on different sublattices are opposed

  13. Etching characteristics of high-k dielectric HfO{sub 2} thin films in inductively coupled fluorocarbon plasmas

    SciTech Connect (OSTI)

    Takahashi, Kazuo; Ono, Kouichi; Setsuhara, Yuichi [Department of Aeronautics and Astronautics, Kyoto University, Yoshida-Honmachi, Sakyo-ku, Kyoto 606-8501 (Japan)

    2005-11-15T23:59:59.000Z

    Inductively coupled fluorocarbon (CF{sub 4}/Ar and C{sub 4}F{sub 8}/Ar) plasmas were used to etch HfO{sub 2}, which is a promising high-dielectric-constant material for the gate of complementary metal-oxide-semiconductor devices. The etch rates of HfO{sub 2} in CF{sub 4}/Ar plasmas exceeded those in C{sub 4}F{sub 8}/Ar plasmas. The tendency for etch rates to become higher in fluorine-rich (high F/C ratio) conditions indicates that HfO{sub 2} can be chemically etched by fluorine-containing species. In C{sub 4}F{sub 8}/Ar plasmas with a high Ar dilution ratio, the etch rate of HfO{sub 2} increased with increasing bias power. The etch rate of Si, however, decreased with bias power, suggesting that the deposition of carbon-containing species increased with increasing the power and inhibited the etching of Si. The HfO{sub 2}/Si selectivity monotonically increased with increasing power, then became more than 5 at the highest tested bias power. The carbon-containing species to inhibit etching of Si play an important role in enhancing the HfO{sub 2}/Si selectivity in C{sub 4}F{sub 8}/Ar plasmas.

  14. Effects of N{sub 2}, O{sub 2}, and Ar plasma treatments on the removal of crystallized HfO{sub 2} film

    SciTech Connect (OSTI)

    Chen Jinghao; Yoo, Won Jong; Chan, Daniel S.H. [Silicon Nano Device Laboratory, Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore 117576 (Singapore)

    2006-01-15T23:59:59.000Z

    The effects of plasma treatment using Ar, N{sub 2}, and O{sub 2} on the removal of crystallized HfO{sub 2} films in a dilute HF solution were studied. The resulting damage in source and drain regions, and recess in isolation regions were also investigated. It was found that plasma nitridation with an ion energy of several hundred electron volts can lower the wet etch resistance of crystallized HfO{sub 2} films up to 70 A thick through the generation of Hf-N bonds. However, thermal nitridation did not introduce sufficient nitrogen into bulk crystallized HfO{sub 2} films to lower wet etch resistance. Plasma nitridation without bias power introduced nitrogen to the crystallized HfO{sub 2} in the region only within 10 A of the surface. The enhancement of the etch rate of crystallized HfO{sub 2} in dilute HF and the amount of recess in the active and isolation regions using N{sub 2}, O{sub 2}, and Ar plasma treatment have been evaluated. Results show that N{sub 2} plasma treatment is the most effective in enhancing the removal rate of crystallized HfO{sub 2} in dilute HF and minimizing recess on substrate among the plasmas studied.

  15. Isothermal oxidation behavior of ternary Zr-Nb-Y alloys at high temperature

    SciTech Connect (OSTI)

    Prajitno, Djoko Hadi, E-mail: djokohp@batan.go.id [Research Center for Nuclear Materials and Radiometry, Jl. Tamansari 71, Bandung 40132 (Indonesia); Soepriyanto, Syoni; Basuki, Eddy Agus [Metallurgy Engineering, Institute Technology Bandung, Jl. Ganesha 10, Bandung 40132 (Indonesia); Wiryolukito, Slameto [Materials Engineering, Institute Technology Bandung, Jl. Ganesha 10, Bandung 40132 (Indonesia)

    2014-03-24T23:59:59.000Z

    The effect of yttrium content on isothermal oxidation behavior of Zr-2,5%Nb-0,5%Y, Zr-2,5%Nb-1%Y Zr-2,5%Nb-1,5%Y alloy at high temperature has been studied. High temperature oxidation carried out at tube furnace in air at 600,700 and 800°C for 1 hour. Optical microscope is used for microstructure characterization of the alloy. Oxidized and un oxidized specimen was characterized by x-ray diffraction. In this study, kinetic oxidation of Zr-2,5%Nb with different Y content at high temperature has also been studied. Characterization by optical microscope showed that microstructure of Zr-Nb-Y alloys relatively unchanged and showed equiaxed microstructure. X-ray diffraction of the alloys depicted that the oxide scale formed during oxidation of zirconium alloys is monoclinic ZrO2 while unoxidised alloy showed two phase ? and ? phase. SEM-EDS examination shows that depletion of Zr composition took place under the oxide layer. Kinetic rate of oxidation of zirconium alloy showed that increasing oxidation temperature will increase oxidation rate but increasing yttrium content in the alloys will decrease oxidation rate.

  16. Quantitative phase analysis of Mg:ZrO{sub 2} nanoparticles by Rietveld refinement method

    SciTech Connect (OSTI)

    Balaji, V., E-mail: thangadurai.p@gmail.com; Senthilkumaran, S., E-mail: thangadurai.p@gmail.com; Thangadurai, P., E-mail: thangadurai.p@gmail.com [Center for Nano Science and Technology, Pondicherry University, Puducherry- 605014 (India)

    2014-04-24T23:59:59.000Z

    To quantify the structural phases of nanocrystalline ZrO{sub 2} doped with Mg ions of varying concentrations (3, 5, 10, 15 and 20%) and annealed at different temperatures. Magnesia doped zirconia was prepared by chemical co-precipitation method and annealed up to 1000°C. The monoclinic and tetragonal phases present in Mg:ZrO{sub 2} were quantified using Rietveld refinement analysis of the X-ray diffraction data and compared with the Direct method based on peak intensity calculations. Tetragonal phase was dominant in the 600°C annealed Mg:ZrO{sub 2} for all Mg concentrations.

  17. Mechanisms and selectivity for etching of HfO{sub 2} and Si in BCl{sub 3} plasmas

    SciTech Connect (OSTI)

    Wang Chunyu; Donnelly, Vincent M. [Department of Chemical and Biomolecular Engineering, University of Houston, 4800 Calhoun Road, Houston, Texas 77204 (United States)

    2008-07-15T23:59:59.000Z

    The authors have investigated plasma etching of HfO{sub 2}, a high dielectric constant material, and poly-Si in BCl{sub 3} plasmas. Etching rates were measured as a function of substrate temperature (T{sub s}) at several source powers. Activation energies range from 0.2 to 1.0 kcal/mol for HfO{sub 2} and from 0.8 to 1.8 kcal/mol for Si, with little or no dependence on source power (20-200 W). These low activation energies suggest that product removal is limited by chemical sputtering of the chemisorbed Hf or Si-containing layer, with a higher T{sub s} only modestly increasing the chemical sputtering rate. The slightly lower activation energy for HfO{sub 2} results in a small improvement in selectivity over Si at low temperature. The surface layers formed on HfO{sub 2} and Si after etching in BCl{sub 3} plasmas were also investigated by vacuum-transfer x-ray photoelectron spectroscopy. A thin boron-containing layer was observed on partially etched HfO{sub 2} and on poly-Si after etching through HfO{sub 2} films. For HfO{sub 2}, a single B(1s) feature at 194 eV was ascribed to a heavily oxidized species with bonding similar to B{sub 2}O{sub 3}. B(1s) features were observed for poly-Si surfaces at 187.6 eV (B bound to Si), 189.8 eV, and 193 eV (both ascribed to BO{sub x}Cl{sub y}). In the presence of a deliberately added 0.5% air, the B-containing layer on HfO{sub 2} is largely unaffected, while that on Si converts to a thick layer with a single B(1s) peak at 194 eV and an approximate stoichiometry of B{sub 3}O{sub 4}Cl.

  18. HF-based etching processes for improving laser damage resistance of fused silica optical surfaces

    SciTech Connect (OSTI)

    Suratwala, T I; Miller, P E; Bude, J D; Steele, R A; Shen, N; Monticelli, M V; Feit, M D; Laurence, T A; Norton, M A; Carr, C W; Wong, L L

    2010-02-23T23:59:59.000Z

    The effect of various HF-based etching processes on the laser damage resistance of scratched fused silica surfaces has been investigated. Conventionally polished and subsequently scratched fused silica plates were treated by submerging in various HF-based etchants (HF or NH{sub 4}F:HF at various ratios and concentrations) under different process conditions (e.g., agitation frequencies, etch times, rinse conditions, and environmental cleanliness). Subsequently, the laser damage resistance (at 351 or 355 nm) of the treated surface was measured. The laser damage resistance was found to be strongly process dependent and scaled inversely with scratch width. The etching process was optimized to remove or prevent the presence of identified precursors (chemical impurities, fracture surfaces, and silica-based redeposit) known to lead to laser damage initiation. The redeposit precursor was reduced (and hence the damage threshold was increased) by: (1) increasing the SiF{sub 6}{sup 2-} solubility through reduction in the NH4F concentration and impurity cation impurities, and (2) improving the mass transport of reaction product (SiF{sub 6}{sup 2-}) (using high frequency ultrasonic agitation and excessive spray rinsing) away from the etched surface. A 2D finite element crack-etching and rinsing mass transport model (incorporating diffusion and advection) was used to predict reaction product concentration. The predictions are consistent with the experimentally observed process trends. The laser damage thresholds also increased with etched amount (up to {approx}30 {micro}m), which has been attributed to: (1) etching through lateral cracks where there is poor acid penetration, and (2) increasing the crack opening resulting in increased mass transport rates. With the optimized etch process, laser damage resistance increased dramatically; the average threshold fluence for damage initiation for 30 {micro}m wide scratches increased from 7 to 41 J/cm{sup 2}, and the statistical probability of damage initiation at 12 J/cm{sup 2} of an ensemble of scratches decreased from {approx}100 mm{sup -1} of scratch length to {approx}0.001 mm{sup -1}.

  19. Effect of electron-phonon interaction on resistivity of some heavy fermion (HF) systems

    SciTech Connect (OSTI)

    Sahoo, J., E-mail: jitendrasahoo2008@gmail.com [Assistant Director, Regional Office of Vocational Education, Sambalpur, Odisha-768004 (India); Shadangi, N. [Dept. of Physics, Silicon Institute of Technology, Sambalpur, Odisha-768200 (India); Nayak, P. [School of Physics, Sambalpur University, Sambalpur, Odisha-768019 (India)

    2014-04-24T23:59:59.000Z

    Here, we have analyzed the electron-phonon interaction in the Periodic Anderson Model (PAM) to describe the temperature dependence of resistivity in some heavy fermion (HF) systems for finite wave vector (q) and for finite temperature (T). Since the resistivity is related to the imaginary part of the electron self energy, the expression for the same is evaluated through double time temperature dependant Green function technique of the Zubarev type. The effect of different system parameters namely the position of 4f level, E{sub 0} and the electron - phonon coupling strengths on resistivity have been studied. The results obtained give satisfactory explanations to the experimental observations.

  20. Comparison of femtosecond and nanosecond laser-induced damage in HfO{sub 2} single-layer film and HfO{sub 2}-SiO{sub 2} high reflector

    SciTech Connect (OSTI)

    Yuan Lei; Zhao Yuanan; Shang Guangqiang; Wang Chengren; He Hongbo; Shao Jianda; Fan Zhengxiu [Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China) and Graduate School of the Chinese Academy of Sciences, Beijing 100039 (China); Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China); Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China) and Graduate School of the Chinese Academy of Sciences, Beijing 100039 (China); Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China)

    2007-03-15T23:59:59.000Z

    HfO{sub 2} single layers, 800 nm high-reflective (HR) coating, and 1064 nm HR coating were prepared by electron-beam evaporation. The laser-induced damage thresholds (LIDTs) and damage morphologies of these samples were investigated with single-pulse femtosecond and nanosecond lasers. It is found that the LIDT of the HfO{sub 2} single layer is higher than the HfO{sub 2}-SiO{sub 2} HR coating in the femtosecond regime, while the situation is opposite in the nanosecond regime. Different damage mechanisms are applied to study this phenomenon. Damage morphologies of all samples due to different laser irradiations are displayed.

  1. Suppression of near-edge optical absorption band in sputter deposited HfO{sub 2}-Al{sub 2}O{sub 3} nanolaminates containing nonmonoclinic HfO{sub 2}

    SciTech Connect (OSTI)

    Hoppe, E. E.; Aita, C. R. [Advanced Coatings Experimental Laboratory, University of Wisconsin-Milwaukee, P.O. Box 784, Milwaukee, Wisconsin 53201 (United States)

    2008-04-07T23:59:59.000Z

    Nanolaminates of polycrystalline (tetragonal+orthorhombic) HfO{sub 2} and amorphous Al{sub 2}O{sub 3} are sputter deposited on unheated fused SiO{sub 2}, air annealed at 573-1273 K, and analyzed by x-ray diffraction and spectrophometry. Significant O 2p{yields}Hf 5d interband absorption occurs in all films at energy E{>=}6.2 eV. For E<6.2 eV, films annealed below 1273 K retain a featureless optical absorption edge despite further crystallization. A band with a 5.65 eV onset concurrently develops with m-HfO{sub 2} crystallization after a 1273 K anneal, indicating this phase and not nanocrystallinity per se is responsible for increased absorption.

  2. Proton-induced cross sections relevant to production of 225Ac and 223Ra in natural thorium targets below 200 MeV

    E-Print Network [OSTI]

    J. W. Weidner; S. G. Mashnik; K. D. John; F. Hemez; B. Ballard; H. Bach; E. R. Birnbaum; L. J. Bitteker; A. Couture; D. Dry; M. E. Fassbender; M. S. Gulley; K. R. Jackman; J. L. Ullmann; L. E. Wolfsberg; F. M. Nortier

    2012-05-15T23:59:59.000Z

    Cross sections for 223,225Ra, 225Ac and 227Th production by the proton bombardment of natural thorium targets were measured at proton energies below 200 MeV. Our measurements are in good agreement with previously published data and offer a complete excitation function for 223,225Ra in the energy range above 90 MeV. Comparison of theoretical predictions with the experimental data shows reasonable-to-good agreement. Results indicate that accelerator-based production of 225Ac and 223Ra below 200 MeV is a viable production method.

  3. Phase formation in Zr/Fe multilayers during Kr ion irradiation.

    SciTech Connect (OSTI)

    Motta, A. T.

    1998-01-29T23:59:59.000Z

    A detailed study has been conducted of the effect of Kr ion irradiation on phase formation in Zr-Fe metallic multilayers, using the Intermediate Voltage Electron Microscopy (IVEM) at Argonne National Laboratory. Metallic multilayers were prepared with different overall compositions (near 50-50 and Fe-rich), and with different wavelengths (repetition thicknesses). These samples were irradiated with 300 keV Kr ions at various temperatures to investigate the final products, as well as the kinetics of phase formation. For the shorter wavelength samples, the final product was in all cases an amorphous Zr-Fe phase, in combination with Fe, while specially for the larger wavelength samples, in the Fe-rich samples the intermetallic compounds ZrFe{sub 2} and Zr{sub 3}Fe were formed in addition to the amorphous phase. The dose to full reaction decreases with temperature, and with wavelength in a manner consistent with a diffusion-controlled reaction.

  4. Atomistic Modeling of Displacement Cascades in La2Zr2O7 Pyrochlore...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    static calculations. Citation: Chartier A, C Meis, JP Crocombette, LR Corrales, and WJ Weber.2003."Atomistic Modeling of Displacement Cascades in La2Zr2O7 Pyrochlore."Physical...

  5. Analysis of the electronic structure of ZrO{sub 2} by Compton spectroscopy

    SciTech Connect (OSTI)

    Mahammad, F. M.; Mahammed, S. F. [University of Tikrit 42, Department of Physics (Iraq)] [University of Tikrit 42, Department of Physics (Iraq); Kumar, R.; Vijay, Y. K.; Sharma, B. K. [University of Rajasthan, Department of Physics (India)] [University of Rajasthan, Department of Physics (India); Sharma, G., E-mail: gsphysics@gmail.com [University of Kota, Department of Pure and Applied Physics (India)

    2013-07-15T23:59:59.000Z

    The electronic structure of ZrO{sub 2} is studied using the Compton scattering technique. The first-ever Compton profile measurement on polycrystalline ZrO{sub 2} was obtained using 59.54 keV gamma-rays emanating from the {sup 241}Am radioisotope. To explain the experimental data, we compute theoretical Compton profile values using the method of linear combination of atomic orbitals in the framework of density functional theory. The correlation scheme proposed by Perdew-Burke-Ernzerhof and the exchange scheme of Becke are considered. The ionic-model-based calculations for a number of configurations, i.e., Zr{sup +x}(O{sup -x/2}){sub 2} (0 {<=} x {<=} 2), are also performed to estimate the charge transfer on compound formation, and the study supports transfer of 1.5 electrons from Zr to O atoms.

  6. Oxygen impurity and microalloying effect in a Zr-based bulk metallic glass alloy

    E-Print Network [OSTI]

    Pennycook, Steve

    Oxygen impurity and microalloying effect in a Zr-based bulk metallic glass alloy C.T. Liu*, M composition Zr­10 at.%Al­5% Ti­17.9% Cu­14.6% Ni (BAM-11) was used to study the effects of oxygen impurities and microalloying on the microstructure and mechanical properties. Oxygen impurity at a level of 3000 appm

  7. Process and properties of electroless Ni-Cu-P-ZrO{sub 2} nanocomposite coatings

    SciTech Connect (OSTI)

    Ranganatha, S. [Department of Studies in Chemistry, School of Chemical Sciences, Kuvempu University, Shankaraghatta 577451, Shimoga, Karnataka (India)] [Department of Studies in Chemistry, School of Chemical Sciences, Kuvempu University, Shankaraghatta 577451, Shimoga, Karnataka (India); Venkatesha, T.V., E-mail: drtvvenkatesha@yahoo.co.uk [Department of Studies in Chemistry, School of Chemical Sciences, Kuvempu University, Shankaraghatta 577451, Shimoga, Karnataka (India); Vathsala, K. [Nanotribology Laboratory, Mechanical engineering department, Indian Institute of Science, Bangalore (India)] [Nanotribology Laboratory, Mechanical engineering department, Indian Institute of Science, Bangalore (India)

    2012-03-15T23:59:59.000Z

    Highlights: Black-Right-Pointing-Pointer The Ni-P and Ni-P-Cu-ZrO{sub 2} coatings were produced by electroless technique. Black-Right-Pointing-Pointer The influence of copper and ZrO{sub 2} nanoparticles on Ni-P was studied. Black-Right-Pointing-Pointer Surface morphology, structure and electrochemical behavior were evaluated. Black-Right-Pointing-Pointer The Ni-Cu-P-ZrO{sub 2} and Ni-P-ZrO{sub 2} coatings are more resistant to corrosion than Ni-P. Black-Right-Pointing-Pointer Introduction of Cu and ZrO{sub 2} in the matrix aids to the enhancement of microhardness. -- Abstract: Electroless Ni-Cu-P-ZrO{sub 2} composite coating was successfully obtained on low carbon steel matrix by electroless plating technique. Coatings with different compositions were obtained by varying copper as ternary metal and nano sized zirconium oxide particles so as to obtain elevated corrosion resistant Ni-P coating. Microstructure, crystal structure and composition of deposits were analyzed by SEM, EDX and XRD techniques. The corrosion behavior of the deposits was studied by anodic polarization, Tafel plots and electrochemical impedance spectroscopy (EIS) in 3.5% sodium chloride solution. The ZrO{sub 2} incorporated Ni-P coating showed higher corrosion resistance than plain Ni-P. The introduction of copper metal into Ni-P-ZrO{sub 2} enhanced the protection ability against corrosion. The influence of copper metal and nanoparticles on microhardness of coatings was evaluated.

  8. Effective work function of Pt, Pd, and Re on atomic layer deposited HfO{sub 2}

    SciTech Connect (OSTI)

    Gu Diefeng; Dey, Sandwip K.; Majhi, Prashant [Department of Chemical and Materials Engineering, Arizona State University, Tempe, Arizona 85287-6006 (United States) and Department of Electrical Engineering, Arizona State University, Tempe, Arizona 85287-5706 (United States); Planar CMOS Scaling, SEMATECH, Austin, Texas 78741 (United States)

    2006-08-21T23:59:59.000Z

    Platinum and Pd show a significant difference in work function on SiO{sub 2} and high-K materials (HfO{sub 2}). The effective metal work functions for Pd, Pt, and Re on atomic layer deposited HfO{sub 2}, which are different from the vacuum work function and important for device threshold voltage control, are measured by the C-V method. The difference is attributed to the dipoles at the metal/HfO{sub 2} interface, which is a result of charge transfer across the interface. Moreover, the extracted charge neutrality level and screening parameter are correlated with the phase development, film stoichiometry, and density of interface states at the metal/high-K interface.

  9. Plasma and vacuum ultraviolet induced charging of SiO{sub 2} and HfO{sub 2} patterned structures

    SciTech Connect (OSTI)

    Lauer, J. L.; Upadhyaya, G. S.; Sinha, H.; Kruger, J. B.; Nishi, Y.; Shohet, J. L. [Plasma Processing and Technology Laboratory and Department of Electrical and Computer Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States); Stanford Nanofabrication Facility, Stanford University, Stanford, California 94303 (United States); Stanford University, Stanford, California 94305 (United States); Plasma Processing and Technology Laboratory and Department of Electrical and Computer Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States)

    2012-01-15T23:59:59.000Z

    The authors compare the effects of plasma charging and vacuum ultraviolet (VUV) irradiation on oxidized patterned Si structures with and without atomic-layer-deposited HfO{sub 2}. It was found that, unlike planar oxidized Si wafers, oxidized patterned Si wafers charge up significantly after exposure in an electron-cyclotron resonance plasma. The charging is dependent on the aspect ratio of the patterned structures. This is attributed to electron and/or ion shading during plasma exposure. The addition of a 10 nm thick HfO{sub 2} layer deposited on top of the oxidized silicon structures increases the photoemission yield during VUV irradiation, resulting in more trapped positive charge compared to patterns without the HfO{sub 2} dielectric.

  10. Local elastic modulus of RF sputtered HfO{sub 2} thin film by atomic force acoustic microscopy

    SciTech Connect (OSTI)

    Jena, S., E-mail: shuvendujena9@gmail.com; Tokas, R. B., E-mail: shuvendujena9@gmail.com; Sarkar, P., E-mail: shuvendujena9@gmail.com; Thakur, S.; Sahoo, N. K. [Atomic and Molecular Physics Division, Bhabha Atomic Research Centre, Trombay, Mumbai-400 085 (India); Misal, J. S.; Rao, K. D. [Optics and Thin Film Laboratory, Autonagar, BARC-Vizag, Visakhapatnam-530 012 (India)

    2014-04-24T23:59:59.000Z

    Atomic force acoustic microscopy (AFAM) is a useful nondestructive technique for measurement of local elastic modulus of materials at nano-scale spatial resolution by measuring the contact resonance spectra for higher order modes of the AFM cantilever. The elastic modulus of RF sputtered HfO{sub 2} thin film has been measured quantitatively, using reference approach in which measurements are performed on the test and reference samples. Using AFAM, the measured elastic modulus of the HfO{sub 2} thin film is 223±27 GPa, which is in agreement with the literature value of 220±40 GPa for atomic layer deposited HfO{sub 2} thin film using nanoindentation technique.

  11. First observation of /sup 162/Hf decay completion of an alpha -decay chain

    E-Print Network [OSTI]

    Schrewe, U J; Hagberg, E; Hardy, J C; Koslowsky, V T; Schmeing, H; Sharma, K S

    1981-01-01T23:59:59.000Z

    The new isotope /sup 162/Hf (T/sub 1/2/=(37.6+or-0.8)s) is produced in a /sup 142/Nd (/sup 24/Mg,4n) reaction. The activities produced in this reaction are transported to a measuring station by use of a He- jet system. Decay properties are observed with alpha -, gamma -, and gamma - gamma -spectroscopy. The Z-assignment of the new isotope is based on a cross bombardment on /sup 141/Pr target and on the results of a gamma -X-ray coincidence measurement. The mass assignment is deduced from the excitation function measurements. From the measured alpha -decay energy E/sub alpha /=4308 (10) keV new mass values are derived for /sup 162/Hf, /sup 166/W, /sup 170/Os, /sup 174/Pt, and /sup 178/Hg. These new mass values make it possible to establish systematics of two-proton and one-proton binding energies far from stability. (20 refs).

  12. Effects of shock waves on the performance of a cw supersonic HF chemical laser

    SciTech Connect (OSTI)

    Stricker, J.; Waichman, K.

    1984-09-01T23:59:59.000Z

    The effects of oblique shock waves on the gain and the output power of a cw supersonic HF chemical laser are theoretically investigated. A one-dimensional model is used to solve the flow of a premixed H/sub 2/--SF/sub 6/--H/sub e/ or H/sub 2/--F/sub 2/--H/sub e/ mixture through the resonator, allowing the presence of oblique shock waves in the flow. It is shown that a shock wave significantly affects the laser performance due to the gas compression at the shock front and due to acceleration of the chemical and energy transfer processes. It was found that immediately behind the shock front the gain coefficients and the photon energy sharply increase and further downstream they fall off rapidly, thus the profiles of the gain and radiation flux become narrower along the flow direction. Integration of the radiation flux along the cavity coordinate reveals that in some cases the total available power is significantly higher than the available power obtained in the undisturbed flow. For HF lasers pumped by the chain reactions it was found that choking occurs over a wide range of flow parameters including very weak shock waves. This is due to the large amount of heat released by the exothermic reactions.

  13. Measurements of spatial and frequency coherence of an equatorial hf path during spread-F

    SciTech Connect (OSTI)

    Fitzgerald, T.J.; Argo, P.E.; Carlos, R.C.

    1993-01-01T23:59:59.000Z

    In August 1990, the authors set up an hf path on the equatorial path between Maloelap Atoll and Bikini Atoll. This path, which had a range of 702 km, reflected in the ionosphere approximately 100 km north of the Altair radar location on Kwajalein. Transmitters at Maloelap broadcasted four cw tones within bandwidth of either 4 kHz, 9 kHz, or 70 kHz to be used to determine frequency coherence and also a phase-coded pseudo random sequence with a bandwidth of 60 kHz (channel probe) to be used to determine time delay spread. A spatial array of antennas was deployed at Bikini to measure spatial and frequency coherence using the cw broadcasts. The system was run in the post-sunset time period over two weeks during which almost every night showed significant degradation due to spread F resulting in rapid fading, decreased spatial and frequency coherence, and increased time delay spread. Doppler spreads of greater than 20 Hz were not uncommon, and the spatial correlation distances and frequency coherence bandwidths became so small (50 meters and 1 kHz respectively) that the experiment had to be readjusted. Measurements taken by the Altair incoherent scatter radar and the CUPRI 50 MHz coherent scatter radar indicate that although the bistatic hf channel is affected by the large scale plume structures, most of the [open quotes]damage[close quotes] is done by the bottomside spread F.

  14. Measurements of spatial and frequency coherence of an equatorial hf path during spread-F

    SciTech Connect (OSTI)

    Fitzgerald, T.J.; Argo, P.E.; Carlos, R.C.

    1993-07-01T23:59:59.000Z

    In August 1990, the authors set up an hf path on the equatorial path between Maloelap Atoll and Bikini Atoll. This path, which had a range of 702 km, reflected in the ionosphere approximately 100 km north of the Altair radar location on Kwajalein. Transmitters at Maloelap broadcasted four cw tones within bandwidth of either 4 kHz, 9 kHz, or 70 kHz to be used to determine frequency coherence and also a phase-coded pseudo random sequence with a bandwidth of 60 kHz (channel probe) to be used to determine time delay spread. A spatial array of antennas was deployed at Bikini to measure spatial and frequency coherence using the cw broadcasts. The system was run in the post-sunset time period over two weeks during which almost every night showed significant degradation due to spread F resulting in rapid fading, decreased spatial and frequency coherence, and increased time delay spread. Doppler spreads of greater than 20 Hz were not uncommon, and the spatial correlation distances and frequency coherence bandwidths became so small (50 meters and 1 kHz respectively) that the experiment had to be readjusted. Measurements taken by the Altair incoherent scatter radar and the CUPRI 50 MHz coherent scatter radar indicate that although the bistatic hf channel is affected by the large scale plume structures, most of the {open_quotes}damage{close_quotes} is done by the bottomside spread F.

  15. Interplay between gadolinium dopants and oxygen vacancies in HfO{sub 2}: A density functional theory plus Hubbard U investigation

    SciTech Connect (OSTI)

    Zhang, Wei [Department of Criminal Science and Technology, Nanjing Forest Police College, Nanjing 210023 (China); Hou, Z. F., E-mail: zhufeng.hou@gmail.com [Department of Electronic Science, Xiamen University, Xiamen 361005 (China)

    2014-03-28T23:59:59.000Z

    The influence of gadolinium (Gd) doping on the oxygen vacancy (V{sub O}) in monoclinic HfO{sub 2} have been studied by the first-principles calculations within the spin-polarized generalized gradient approximation plus Hubbard U approach. It is found that the Gd dopant and V{sub O} show strong attractive interaction, resulting in a cooperative effect that the substitution of Gd for Hf (Gd{sub Hf}) would increase the probability of oxygen vacancies generation and vice versa. The Gd{sub Hf} is more energetically favorable to be next to the vacancy site of a three-coordinated oxygen (O3), forming a complex defect Gd{sub Hf} + V{sub O}. A single Gd{sub Hf} acts a hole donor and passivates the defect states of V{sub O}. Our results suggest that the decrease of the V{sub O}-related defect states observed in the photoluminescence spectra of Gd-HfO{sub 2} is because Gd doping passivates the defect states of V{sub O}, rather than caused by decrease of V{sub O} concentration. Our findings would clarify the debate about the influence of Gd doping on the oxygen vacancies in HfO{sub 2}.

  16. A comparison of EISCAT and HF Doppler observations of a ULF wave D. M. Wright, T. K. Yeoman, J. A. Davies

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    A comparison of EISCAT and HF Doppler observations of a ULF wave D. M. Wright, T. K. Yeoman, J. A, Wright et al. (1997) presented a detailed study of ULF wave signatures observed by a new sounder at high observed by HF Doppler Correspondence to: D. M. Wright Presented at the Eighth International EISCAT

  17. High-Linear Energy Transfer Irradiation Targeted to Skeletal Metastases by the Alpha Emitter Ra-223: Adjuvant or Alternative to Conventional Modalities?

    SciTech Connect (OSTI)

    Bruland, Oyvind S.; Nilsson, Sten; Fisher, Darrell R.; Larsen, Roy H.

    2006-10-15T23:59:59.000Z

    The bone-seeking, alpha-particle emitting radiopharmaceutical Alpharadin, 223RaCl2 (t1/2 = 11.4 days) is under clinical development as a novel treatment for skeletal metastases from breast and prostate cancer. This paper summarizes the current status of preclinical and clinical research on 223RaCl2. Potential advantages of 223Ra to that of external beam irradiation or registered beta-emitting bone-seekers are discussed. Published data of 223Ra dosimetry in mice and a therapeutic study in a skeletal metastases model in nude rats have indicated significant therapeutic potential of bone-seeking alpha-emitters. This paper provides short-term and long-term results from the first clinical single dosage trial. We present data from a repeated dosage study of five consecutive injections of 50 kBq/kg bodyweight, once every third week, or two injections of 125 kBq/kg bodyweight, six weeks apart. Furthermore, preliminary results are given for a randomized phase II trial involving 64 patients with hormone-refractory prostate cancer and painful skeletal metastases who received four monthly injections of 223Ra or saline as an adjuvant to external beam radiotherapy. Also presented are preliminary dose estimates for 223Ra in humans. Results indicate that repeated dosing is feasible and that opportunities are available for combined treatment strategies.

  18. Ab initio study of radium monofluoride, RaF, as a candidate to search for P- and T,P- violation effects

    E-Print Network [OSTI]

    A. D. Kudashov; A. N. Petrov; L. V. Skripnikov; N. S. Mosyagin; T. A. Isaev; R. Berger; A. V. Titov

    2014-09-20T23:59:59.000Z

    Relativistic ab initio calculations have been performed to assess the suitability of RaF for experimental search of P- and T,P-violating interactions. The parameters of P- and T,P-odd terms of the spin-rotational Hamiltonian have been calculated for the ${^2}\\Sigma$ electronic ground state of RaF molecule. They include the parameter $W_a$, which is critical in experimental search for nuclear anapole moment and the parameters $W_d$ and $W_{\\rm SP}$ required to obtain restrictions on the electric dipole moment of the electron and T,P-odd scalar-pseudoscalar interactions, respectively. The parameter $X$ corresponding to the "volume effect" in the T,P$-$odd interaction of the $^{223}$Ra nuclear Schiff moment with electronic shells of RaF has also been computed. Spectroscopic and hyperfine structure constants for $^{223}$RaF and $^{223}$Ra$^+$ have been computed as well, demonstrating the accuracy of the methods employed.

  19. Superlattice Structure and Precipitates in O+ and Zr+ Ion Coimplanted SrTiO3: a Model Waste Form for 90Sr

    SciTech Connect (OSTI)

    Jiang, Weilin; Van Ginhoven, Renee M.; Kovarik, Libor; Jaffe, John E.; Arey, Bruce W.

    2012-07-13T23:59:59.000Z

    We investigate strontium titanate as a model waste form for 90Sr. Implantation with O+ and Zr+ ions, followed by annealing at 1423 K, was performed to simulate 90Sr to 90Zr decays. At low Zr concentrations, we observe formation of a ZrO-Sr superlattice structure. Ab initio calculations indicate that this atomic configuration is energetically favorable. At higher Zr concentrations, we observe precipitates of ZrO2 with a coherently strained interface, or a monolayer of disordered interfacial structure. Potential candidacy of 90SrTiO3 as a waste form for permanent disposal of 90Sr is discussed.

  20. Infrared study on room-temperature atomic layer deposition of HfO{sub 2} using tetrakis(ethylmethylamino)hafnium and remote plasma-excited oxidizing agents

    SciTech Connect (OSTI)

    Kanomata, Kensaku [Graduate School of Science and Engineering, Yamagata University, 4-3-16 Jonan, Yonezawa 992-8510, Japan and Japan Society for the Promotion of Science, 5-3-1 Kojimachi, Chiyoda-ku, Tokyo 102-0083 (Japan); Ohba, Hisashi; Pungboon Pansila, P.; Ahmmad, Bashir; Kubota, Shigeru; Hirahara, Kazuhiro; Hirose, Fumihiko, E-mail: fhirose@yz.yamagata-u.ac.jp [Graduate School of Science and Engineering, Yamagata University, 4-3-16 Jonan, Yonezawa 992-8510 (Japan)

    2015-01-01T23:59:59.000Z

    Room-temperature atomic layer deposition (ALD) of HfO{sub 2} was examined using tetrakis (ethylmethylamino)hafnium (TEMAH) and remote plasma-excited water and oxygen. A growth rate of 0.26?nm/cycle at room temperature was achieved, and the TEMAH adsorption and its oxidization on HfO{sub 2} were investigated by multiple internal reflection infrared absorption spectroscopy. It was observed that saturated adsorption of TEMAH occurs at exposures of ?1?×?10{sup 5}?L (1 L?=?1?×?10{sup ?6} Torr s) at room temperature, and the use of remote plasma-excited water and oxygen vapor is effective in oxidizing the TEMAH molecules on the HfO{sub 2} surface, to produce OH sites. The infrared study suggested that Hf–OH plays a role as an adsorption site for TEMAH. The reaction mechanism of room temperature HfO{sub 2} ALD is discussed in this paper.

  1. Computational investigation of the phase stability and the electronic properties for Gd-doped HfO{sub 2}

    SciTech Connect (OSTI)

    Wang, L. G. [General Research Institute for Nonferrous Metals, Beijing 100088 (China); California Institute of Technology, Pasadena, California 91125 (United States); Xiong, Y.; Xiao, W.; Cheng, L.; Du, J.; Tu, H. [General Research Institute for Nonferrous Metals, Beijing 100088 (China); Walle, A. van de [Brown University, Providence, Rhode Island 02912 (United States); California Institute of Technology, Pasadena, California 91125 (United States)

    2014-05-19T23:59:59.000Z

    Rare earth doping is an important approach to improve the desired properties of high-k gate dielectric oxides. We have carried out a comprehensive theoretical investigation on the phase stability, band gap, formation of oxygen vacancies, and dielectric properties for the Gd-doped HfO{sub 2}. Our calculated results indicate that the tetragonal phase is more stable than the monoclinic phase when the Gd doping concentration is greater than 15.5%, which is in a good agreement with the experimental observations. The dopant's geometric effect is mainly responsible for the phase stability. The Gd doping enlarges the band gap of the material. The dielectric constant for the Gd-doped HfO{sub 2} is in the range of 20–30 that is suitable for high-k dielectric applications. The neutral oxygen vacancy formation energy is 3.2?eV lower in the doped material than in pure HfO{sub 2}. We explain the experimental observation on the decrease of photoluminescence intensities in the Gd-doped HfO{sub 2} according to forming the dopant-oxygen vacancy complexes.

  2. Analytical Potential Energy Surface for the Na + HF NaF + H reaction: Application of Conventional Transition-State Theory

    E-Print Network [OSTI]

    Analytical Potential Energy Surface for the Na + HF NaF + H reaction: Application of Conventional Transition-State Theory Alessandra F. A. Vilela, Ricardo Gargano a Patr´icia R.P. Barreto b a Instituto de from calculation of the rate constant using con- ventional Transition State Theory (TST

  3. NEW ACTIVE LOAD VOLTAGE CLAMP FOR HF-LINK CONVERTERS Petar Ljusev and Michael A.E. Andersen

    E-Print Network [OSTI]

    that incorporates both the main power and auxiliary transformer on the same magnetic core. Keywords: HF not need additional power components, but do have increased control complexity and safety problems. The latter solutions satisfy both the commutation and safety issues, but ask for additional power components

  4. Computer simulations for direct conversion of the HF electromagnetic wave into the upper hybrid wave in ionospheric heating experiments

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Computer simulations for direct conversion of the HF electromagnetic wave into the upper hybrid emissions (SEE). A direct conversion process is proposed as an excitation mech- anism of the upper hybrid, 1996) The electrostatic waves at the UH resonance were assumed to be excited via ``direct conversion

  5. The Long Wavelength Array (LWA): A Large HF/VHF Array for Solar Physics, Ionospheric Science, and Solar Radar

    E-Print Network [OSTI]

    Ellingson, Steven W.

    The Long Wavelength Array (LWA): A Large HF/VHF Array for Solar Physics, Ionospheric Science, and Solar Radar Namir E. Kassim Naval Research Laboratory, Washington, DC 20375 Stephen M. White AFRL will be a powerful tool for solar physics and space weather investigations, through its ability to characterize

  6. Role of hydrogen in Ge/HfO2/Al gate stacks subjected to negative bias temperature instability

    E-Print Network [OSTI]

    Misra, Durgamadhab "Durga"

    Role of hydrogen in Ge/HfO2/Al gate stacks subjected to negative bias temperature instability N 2007; published online 17 January 2008 This work investigates the role of hydrogen and nitrogen in a Ge. Virtually unchanged interface state density as a function of NBTI indicates no atomic hydrogen release from

  7. Gas-phase hydrogen isotope exchange in HF + D2O

    SciTech Connect (OSTI)

    Trowbridge, L.D.

    1982-12-31T23:59:59.000Z

    The gas-phase isotope exchange reaction of HF and D2O has been studied by flow tube and matrix isolation techniques over a range of concentrations and reaction times. The matrix isolation/FTIR gas sampling and analysis technique proved capable of detecting reactants and products even at low concentrations (0.02% and less) and for reaction times down to 10 msec. The reaction under study, however, is sufficiently rapid that it appeared complete at 10 msec even at the lowest reactant concentrations used. From these results, it is therefore possible only to place a lower bound on the reaction rate. This lower bound, arrived at by computer modeling an assumed second order reaction in the flow tube, represents a refinement in the previously established limit by about a factor of 10U and may thus be of utility in UF6 atmospheric release models. 4 refs., 13 figs., 2 tabs.

  8. The effects of zirconia morphology on methanol synthesis from COand H2 over Cu/ZrO2 catalysts: Part I -- Steady-State Studies

    SciTech Connect (OSTI)

    Rhodes, Michael J.; Bell, Alexis T.

    2005-03-21T23:59:59.000Z

    The effect of zirconia phase on the activity and selectivityof Cu/ZrO2 for the hydrogenation of CO has been investigated. Relativelypure t-ZrO2 and m-ZrO2 were prepared with high surface areas (~; 145m2/g). Copper was then deposited onto the surface of these materials byeither incipient-wetness impregnation or deposition-precipitation. For afixed Cu surface area, Cu/m-ZrO2 was tenfold more active for methanolsynthesis than Cu/t-ZrO2 from a feed of 3/1 H2/CO at 3.0 MPa andtemperatures between 473 and 523 K. Cu/m-ZrO2 also exhibited a higherselectivity to methanol. Increasing the Cu surface area on m-ZrO2resulted in further improvement in activity with minimal change inselectivity. Methanol productivity increased linearly for both Cu/t-ZrO2and Cu/m-ZrO2 with increasing Cu surface area. The difference in inherentactivity of each phase paralleled the stronger and larger CO adsorptioncapacity of the Cu/m-ZrO2 as quantified by CO-TPD. The higher COadsorption capacity of Cu/m-ZrO2 is attributed to the presence of a highconcentration of anionic vacancies on the surface of m-ZrO2. Suchvacancies expose cus-Zr4+ cations, which act as Lewis acid centers andenhance the Bronsted acidity of adjacent Zr-OH groups. The presence ofcus-Zr4+ sites and adjacent Bronsted acidic Zr-OH groups contributes tothe adsorption of CO as HCOO-Zr groups, which are the initial precursorsto methanol.

  9. Solid Solubilities of Pu, U, Gd and Hf in Candidate Ceramic Nuclear Wasteforms

    SciTech Connect (OSTI)

    Vance, Eric R.; Carter, M. L.; Lumpkin, G. R.; Day, R. A.; Begg, B. D.

    2001-04-02T23:59:59.000Z

    This goal of this research project was to determine the solid solubility of Pu, U, Gd, and Hf in candidate ceramics for immobilization of high-level nuclear waste. The experimental approach was to saturate each phase by adding more than the solid solubility limit of the given cation, using a nominated substitution scheme, and then analyzing the candidate phase that formed to evaluate the solid solubility limit under firing conditions. Confirmation that the solid solution limit had been reached insofar as other phases rich in the cation of interest was also required. The candidate phases were monazite, titanite, zirconolite, perovskite, apatite, pyrochlore, and brannerite. The valences of Pu and U were typically deduced from the firing atmosphere, and charge balancing in the candidate phase composition as evaluated from electron microscopy, although in some cases it was measured directly by x-ray absorption and diffuse reflectance spectroscopies (for U). Tetravalent Pu and U have restricted (< 0.1 formula units) solid solubility in apatite, titanite, and perovskite. Trivalent Pu has a larger solubility in apatite and perovskite than Pu4+. U3+ appears to be a credible species in reduced perovskite with a solubility of {approximately} 0.25 f.u. as opposed to {approximately} 0.05 f.u. for U4+. Pu4+ is a viable species in monazite and is promoted at lower firing temperatures ({approximately} 800 C) in an air atmosphere. Hf solubility is restricted in apatite, monazite (< 0.1 f.u.), but is {approximately} 0.2 and 0.5 f.u. in brannerite and titanite, respectively. Gd solubility is extended in all phases except for titanite ({approximately} 0.3 f.u.). U5+ was identified by DRS observations of absorption bands in the visible/near infrared photon energy ranges in brannerite and zirconolite, and U4+ in zirconolite was similarly identified.

  10. Laboratory Results Area Lab ID Th-230 Ra-226 Pb-210 Po-210 U-238 ANSI Sum1

    E-Print Network [OSTI]

    Laboratory Results Area Lab ID Th-230 Ra-226 Pb-210 Po-210 U-238 ANSI Sum1 Gamma Reading Area H Area I Confirmation 0405025-2 1.66 5.13 2.88 3.48 0.95 4.55 9741 Clear 11th Street 0405215-3 1.28 4.59 3.55 3.55 1.68 4.37 ++ Area K 0404284-2 14.8 43.4 17.4 13.8 10.6 80.8 15146 Estimated - lab

  11. Melting temperatures of the ZrO{sub 2}-MOX system

    SciTech Connect (OSTI)

    Uchida, T.; Hirooka, S.; Kato, M.; Morimoto, K. [Japan Atomic Energy Agency, 4-33, Muramatsu, Tokai-mura, Naka-gun, Ibaraki 319-1194 (Japan); Sugata, H.; Shibata, K.; Sato, D. [Inspection Development Company, 4-33, Muramatsu, Tokai-mura, Naka-gun, Ibaraki 319-1194 (Japan)

    2013-07-01T23:59:59.000Z

    Severe accidents occurred at the Fukushima Daiichi Nuclear Power Plant Units 1-3 on March 11, 2011. MOX fuels were loaded in the Unit 3. For the thermal analysis of the severe accident, melting temperature and phase state of MOX corium were investigated. The simulated coriums were prepared from 4%Pu-containing MOX, 8%Pu-containing MOX and ZrO{sub 2}. Then X-ray diffraction, density and melting temperature measurements were carried out as a function of zirconium and plutonium contents. The cubic phase was observed in the 25%Zr-containing corium and the tetragonal phase was observed in the 50% and 75%Zr-containing coria. The lattice parameter and density monotonically changed with Pu content. Melting temperature increased with increasing Pu content; melting temperature were estimated to be 2932 K for 4%Pu MOX corium and 3012 K for 8%Pu MOX corium in the 25%ZrO{sub 2}-MOX system. The lowest melting temperature was observed for 50%Zr-containing corium. (authors)

  12. Mechanisms for plasma etching of HfO{sub 2} gate stacks with Si selectivity and photoresist trimming

    SciTech Connect (OSTI)

    Shoeb, Juline; Kushner, Mark J. [Department of Electrical and Computer Engineering, Iowa State University, Ames, Iowa 50011 (United States); Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, Michigan 48109-2122 (United States)

    2009-11-15T23:59:59.000Z

    To minimize leakage currents resulting from the thinning of the insulator in the gate stack of field effect transistors, high-dielectric constant (high-k) metal oxides, and HfO{sub 2} in particular, are being implemented as a replacement for SiO{sub 2}. To speed the rate of processing, it is desirable to etch the gate stack (e.g., metal gate, antireflection layers, and dielectric) in a single process while having selectivity to the underlying Si. Plasma etching using Ar/BCl{sub 3}/Cl{sub 2} mixtures effectively etches HfO{sub 2} while having good selectivity to Si. In this article, results from integrated reactor and feature scale modeling of gate-stack etching in Ar/BCl{sub 3}/Cl{sub 2} plasmas, preceded by photoresist trimming in Ar/O{sub 2} plasmas, are discussed. It was found that BCl{sub n} species react with HfO{sub 2}, which under ion impact, form volatile etch products such as B{sub m}OCl{sub n} and HfCl{sub n}. Selectivity to Si is achieved by creating Si-B bonding as a precursor to the deposition of a BCl{sub n} polymer which slows the etch rate relative to HfO{sub 2}. The low ion energies required to achieve this selectivity then challenge one to obtain highly anisotropic profiles in the metal gate portion of the stack. Validation was performed with data from literature. The effect of bias voltage and key reactant probabilities on etch rate, selectivity, and profile are discussed.

  13. Direct observation of bias-dependence potential distribution in metal/HfO{sub 2} gate stack structures by hard x-ray photoelectron spectroscopy under device operation

    SciTech Connect (OSTI)

    Yamashita, Y. [National Institute for Materials Science, Advanced Electric Materials Center, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); National Institute for Materials Science, NIMS Beamline Station at SPring-8, 1-1-1 Kôto, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan); Yoshikawa, H.; Kobayashi, K. [National Institute for Materials Science, NIMS Beamline Station at SPring-8, 1-1-1 Kôto, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan); Chikyo, T. [National Institute for Materials Science, Advanced Electric Materials Center, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan)

    2014-01-28T23:59:59.000Z

    Although gate stack structures with high-k materials have been extensively investigated, there are some issues to be solved for the formation of high quality gate stack structures. In the present study, we employed hard x-ray photoelectron spectroscopy in operating devices. This method allows us to investigate bias dependent electronic states, while keeping device structures intact. Using this method, we have investigated electronic states and potential distribution in gate metal/HfO{sub 2} gate stack structures under device operation. Analysis of the core levels shifts as a function of the bias voltage indicated that a potential drop occurred at the Pt/HfO{sub 2} interface for a Pt/HfO{sub 2} gate structure, while a potential gradient was not observed at the Ru/HfO{sub 2} interface for a Ru/HfO{sub 2} gate structure. Angle resolved photoelectron spectroscopy revealed that a thicker SiO{sub 2} layer was formed at the Pt/HfO{sub 2} interface, indicating that the origin of potential drop at Pt/HfO{sub 2} interface is formation of the thick SiO{sub 2} layer at the interface. The formation of the thick SiO{sub 2} layer at the metal/high-k interface might concern the Fermi level pinning, which is observed in metal/high-k gate stack structures.

  14. Thermodynamic properties and interfacial layer characteristics of HfO{sub 2} thin films deposited by plasma-enhanced atomic layer deposition

    SciTech Connect (OSTI)

    Kim, Inhoe; Kuk, Seoungwoo; Kim, Seokhoon; Kim, Jinwoo; Jeon, Hyeongtag; Cho, M.-H.; Chung, K.-B. [Division of Materials Science and Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of); Korea Research Institute of Standard and Science, Daejeon 305-600 (Korea, Republic of)

    2007-05-28T23:59:59.000Z

    The thermodynamic properties and interfacial characteristics of HfO{sub 2} thin films that were deposited by the direct plasma atomic layer deposition (DPALD) method are investigated. The as-deposited HfO{sub 2} films that were deposited by the DPALD method show crystallization of the HfO{sub 2} layers, which initiates at approximately the 35th cycle (about 2.8 nm) of the DPALD process. Medium-energy ion scattering analysis reveals that the direct O{sub 2} plasma causes a compositional change in the interfacial layer as the process progresses. With an increase in the number of process cycles, the Si content decreases and the O content increases at that position, so that the HfO{sub 2}-like Hf-silicate layer is formed on top of the interfacial layer. The enhanced physical reactivity of the oxygen ions in the direct plasma and the Hf-silicate layer may be the driving forces that accelerate the early crystallization of the HfO{sub 2} layer in the DPALD process in the as-deposited state.

  15. Creep strength of niobium alloys, Nb-1%Zr and PWC-11

    SciTech Connect (OSTI)

    Titran, R.H.

    1990-01-01T23:59:59.000Z

    A study is being conducted at NASA Lewis Research Center to determine the feasibility of using a carbide particle strengthened Nb-1% Zr base alloy to meet the anticipated temperature and creep resistance requirements of proposed near term space power systems. In order to provide information to aid in the determination of the suitability of the PWC-11 alloy as an alternative to Nb-1% Zr in space power systems this study investigated (1) the long-time high-vacuum creep behavior of the PWC-11 material and the Nb-1% Zr alloy, (2) the effect of prior stress-free thermal aging on this creep behavior, (3) the effect of electron beam (EB) welding on this creep behavior, and (4) the stability of creep strengthening carbide particles. 14 refs., 5 figs., 2 tabs.

  16. Identification of a quasiparticle band in very neutron-rich {sup 104}Zr

    SciTech Connect (OSTI)

    Yeoh, E. Y.; Wang, J. G.; Ding, H. B.; Gu, L.; Xu, Q.; Xiao, Z. G. [Department of Physics, Tsinghua University, Beijing 100084 (China); Zhu, S. J. [Department of Physics, Tsinghua University, Beijing 100084 (China); Department of Physics, Vanderbilt University, Nashville, Tennessee 37235 (United States); Hamilton, J. H.; Ramayya, A. V.; Hwang, J. K.; Liu, S. H. [Department of Physics, Vanderbilt University, Nashville, Tennessee 37235 (United States); Liu, Y. X. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); School of Science, Huzhou Teachers College, Huzhou 313000 (China); Sun, Y. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Department of Physics, Shanghai Jiao Tong University, Shanghai 200240 (China); Luo, Y. X. [Department of Physics, Vanderbilt University, Nashville, Tennessee 37235 (United States); Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Rasmussen, J. O.; Lee, I. Y. [Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

    2010-08-15T23:59:59.000Z

    The high spin levels of a very neutron-rich {sup 104}Zr nucleus have been reinvestigated by measuring the prompt {gamma} rays in the spontaneous fission of {sup 252}Cf. The ground-state band has been confirmed. A new sideband has been identified with a band-head energy at 1928.7 keV. The projected shell model is employed to investigate the band structure of {sup 104}Zr. The results of calculated levels are in good agreement with the experimental data, and suggest that the new band in {sup 104}Zr may be based on the neutron {nu}5/2{sup -}[532] x {nu}3/2{sup +}[411] configuration.

  17. Photocatalytic studies of Ho–Zr–O nano-composite with controllable composition and defects

    SciTech Connect (OSTI)

    Du, Weimin, E-mail: duweimin75@gmail.com [College of Chemistry and Chemical Engineering, Anyang Normal University, Anyang, Henan 455000 (China); Zhao, Guoyan; Chang, Hongxun; Shi, Fei; Zhu, Zhaoqiang [College of Chemistry and Chemical Engineering, Anyang Normal University, Anyang, Henan 455000 (China); Qian, Xuefeng [School of Chemistry and Chemical Technology, Shanghai Jiao Tong University, Shanghai 200240 (China)

    2013-09-15T23:59:59.000Z

    With the help of sol–gel method assisted by melting salt, a series of Ho–Zr–O nano-composite with controllable composition and defects have been successfully prepared. Characterization results show that the positions, intensity, and width of the X-ray diffraction peaks of the products have a regular variation with the increase of zirconium element which implies the gradual changes of crystal spacing and product size. At the same time, the molar ratios between holmium and zirconium ions are consistent with the chemical formula and both of them are uniformly distributed in products further showing the perfect formation of targeted materials. Optical properties reveal that diversified defect forms of Ho–Zr–O nano-composite lead to the different absorptions of visible light. Photocatalytic experiments demonstrate Zr{sub 0.8}Ho{sub 0.2}O{sub 2??} nano-crystals have excellent visible-light-responsive photocatalytic activities on some familiar dyes (e.g.: methylene blue and Rhodamine B) which results from the special defect structure, better absorption of visible light and larger specific surface area. It follows that Zr{sub 0.8}Ho{sub 0.2}O{sub 2??} nano-crystals are a new kind of visible-light-responsive photocatalysts with better prospects in conversion and utilization of solar energy. Also, the present melting salt assisted route might be generalized to synthesize other AxByOz composite oxide nano-crystals with more complicated structures. - Highlights: • Ho–Zr–O nano-composite with controllable composition and defects has been obtained. • Diversified defect forms of products lead to the different visible light absorption. • Zr{sub 0.8}Ho{sub 0.2}O{sub 2??} nano-crystals have excellent photocatalytic activities.

  18. {sup 226}Ra and {sup 231}Pa systematics of axial MORB, crustal residence ages, and magma chamber characteristics at 9--10{degree}N East Pacific Rise

    SciTech Connect (OSTI)

    Goldstein, S.J.; Murrell, M.T. [Los Alamos National Lab., NM (United States); Perfit, M.R. [Univ., of Florida, Gainesville, FL (United States). Dept. of Geology; Batiza, R. [Univ., of Hawaii, Honolulu, HI (United States); Fornari, D.J. [Woods Hole Oceanographic Institution, MA (United States). Dept. of Geology and Geophysics

    1994-06-01T23:59:59.000Z

    Mass spectrometric measurements of {sup 30}Th-22{sup 226}Ra and {sup 235}-U{sup 231}Pa disequilibria for axial basalts are used to determine crustal residence ages for MORB magma and investigate the temporal and spatial characteristics of axial magma chambers (AMC) at 9--10{degrees}N East Pacific Rise (EPR). Relative crustal residence ages can be calculated from variations in {sup 226}Ra/{sup 230}Th and {sup 231}Pa/{sup 235}U activity ratios for axial lavas, if (1) mantle sources and melting are uniform, and mantle transfer times are constant or rapid for axial N-MORB, and (2) {sup 231}Pa/{sup 235}U and {sup 226}Ra/{sup 230}Th in the melt are unaffected by shallow level fractional crystallization. Uniform Th, Sr, and Nd isotopic systematics and incompatible element ratios for N-MORB along the 9--10{degrees}N segment indicate that mantle sources and transfer times are similar. In addition, estimated bulk solid/melt partition coefficients for U, Th, and Pa are small, hence effects of fractional crystallization on {sup 231}Pa/{sup 235}U ratios for the melt are expected to be negligible. However, fractional crystallization of plagioclase in the AMC would lower {sup 226}Ra/{sup 230}Th ratios in the melt and produce a positive bias in {sup 226}Ra crustal residence ages for fractionated lavas.

  19. Total ionizing dose effect of ?-ray radiation on the switching characteristics and filament stability of HfOx resistive random access memory

    SciTech Connect (OSTI)

    Fang, Runchen; Yu, Shimeng, E-mail: shimengy@asu.edu [School of Computing, Informatics, and Decision Systems Engineering, Arizona State University, Tempe, Arizona 85281 (United States); School of Electrical, Computer, and Energy Engineering, Arizona State University, Tempe, Arizona 85287 (United States); Gonzalez Velo, Yago; Chen, Wenhao; Holbert, Keith E.; Kozicki, Michael N.; Barnaby, Hugh [School of Electrical, Computer, and Energy Engineering, Arizona State University, Tempe, Arizona 85287 (United States)

    2014-05-05T23:59:59.000Z

    The total ionizing dose (TID) effect of gamma-ray (?-ray) irradiation on HfOx based resistive random access memory was investigated by electrical and material characterizations. The memory states can sustain TID level ?5.2 Mrad (HfO{sub 2}) without significant change in the functionality or the switching characteristics under pulse cycling. However, the stability of the filament is weakened after irradiation as memory states are more vulnerable to flipping under the electrical stress. X-ray photoelectron spectroscopy was performed to ascertain the physical mechanism of the stability degradation, which is attributed to the Hf-O bond breaking by the high-energy ?-ray exposure.

  20. Silicon photodiode with selective Zr/Si coating for extreme ultraviolet spectral range

    SciTech Connect (OSTI)

    Aruev, P N; Barysheva, Mariya M; Ber, B Ya; Zabrodskaya, N V; Zabrodskii, V V; Lopatin, A Ya; Pestov, Alexey E; Petrenko, M V; Polkovnikov, V N; Salashchenko, Nikolai N; Sukhanov, V L; Chkhalo, Nikolai I

    2012-10-31T23:59:59.000Z

    The procedure of manufacturing silicon photodiodes with an integrated Zr/Si filter for extreme ultraviolet (EUV) spectral range is developed. A setup for measuring the sensitivity profile of detectors with spatial resolution better than 100 {mu}m is fabricated. The optical properties of silicon photodiodes in the EUV and visible spectral ranges are investigated. Some characteristics of SPD-100UV diodes with Zr/Si coating and without it, as well as of AXUV-100 diodes, are compared. In all types of detectors a narrow region beyond the operating aperture is found to be sensitive to the visible light. (photodetectors)

  1. Deformation Mechanisms in Tube Billets from Zr-1%Nb Alloy under Radial Forging

    SciTech Connect (OSTI)

    Perlovich, Yuriy; Isaenkova, Margarita; Fesenko, Vladimir; Krymskaya, Olga [National Research Nuclear University 'Moscow Engineering Physics Institute', Kashirskoe shosse, 31, Moscow, 115409 (Russian Federation); Zavodchikov, Alexander [Perm Research Technological Institute, Hasan Heroes street, 41, Perm, 614990 (Russian Federation)

    2011-05-04T23:59:59.000Z

    Features of the deformation process by cold radial forging of tube billets from Zr-1%Nb alloy were reconstructed on the basis of X-ray data concerning their structure and texture. The cold radial forging intensifies grain fragmentation in the bulk of billet and increases significantly the latent hardening of potentially active slip systems, so that operation only of the single slip system becomes possible. As a result, in radially-forged billets unusual deformation and recrystallization textures arise. These textures differ from usual textures of {alpha}-Zr by the mutual inversion of crystallographic axes, aligned along the axis of tube.

  2. Galactic Evolution of Sr, Y, Zr: A Multiplicity of Nucleosynthetic Processes

    E-Print Network [OSTI]

    Claudia Travaglio; Roberto Gallino; Enrico Arnone; John Cowan; Faith Jordan; Chris Sneden

    2003-10-07T23:59:59.000Z

    We follow the Galactic enrichment of three easily observed light n-capture elements Sr,Y,and Zr.Input stellar yields have been first separated into their respective main and weak s-process,and r-process components.The s-process yields from AGB stars are computed,exploring a wide range of efficiencies of the major neutron source,13C,and covering both disk and halo metallicities.AGBs have been shown to reproduce the main s-component in the solar system.The concurrent weak s-process,which accounts for the major fraction of the light s-process isotopes in the solar system and occurs in massive stars by the operation of the 22Ne n-source,is discussed in detail.Neither the main s-,nor the weak s-components are shown to contribute significantly to the n-capture element abundances observed in unevolved halo stars.We present a detailed analysis of a large database of spectroscopic observations of Sr,Y,Zr, Ba,and Eu for Galactic stars at various metallicities.Spectroscopic observations of Sr,Y,and Zr to Ba and Eu abundance ratios versus metallicity provide useful diagnostics of the types of n-capture processes forming Sr,Y and Zr.The observed [Sr,Y,Zr/Ba,Eu] ratio is clearly not flat at low metallicities,as we would expect if Ba,Eu and Sr,Y,Zr all had the same r-process origin.We discuss our chemical evolution predictions, taking into account the interplay between different processes to produce Sr-Y-Zr.We find hints for a primary process in low-metallicity massive stars, different from the 'classical s-process' and from the 'classical r-process',that we tentatively define LEPP (Lighter Element Primary Process).This allows us to revise the estimates of the r-process contributions to the solar Sr,Y and Zr abundances,as well as of the contribution to the s-only isotopes 86Sr,87Sr,96Mo.

  3. Physical properties of epitaxial ZrN/MgO(001) layers grown by reactive magnetron sputtering

    SciTech Connect (OSTI)

    Mei, A. B.; Zhang, C.; Sardela, M.; Eckstein, J. N.; Rockett, A. [Departments of Materials Science, Physics, and the Materials Research Laboratory, University of Illinois, 104 South Goodwin, Urbana, Illinois 61801 (United States)] [Departments of Materials Science, Physics, and the Materials Research Laboratory, University of Illinois, 104 South Goodwin, Urbana, Illinois 61801 (United States); Howe, B. M. [Air Force Research Laboratory, Wright Patterson Air Force Base, Dayton, Ohio 45433-7817 (United States)] [Air Force Research Laboratory, Wright Patterson Air Force Base, Dayton, Ohio 45433-7817 (United States); Hultman, L. [Thin Film Physics Division, Department of Physics (IFM), Linköping University, SE-58183 Linköping (Sweden)] [Thin Film Physics Division, Department of Physics (IFM), Linköping University, SE-58183 Linköping (Sweden); Petrov, I.; Greene, J. E. [Departments of Materials Science, Physics, and the Materials Research Laboratory, University of Illinois, 104 South Goodwin, Urbana, Illinois 61801 and Thin Film Physics Division, Department of Physics (IFM), Linköping University, SE-58183 Linköping (Sweden)] [Departments of Materials Science, Physics, and the Materials Research Laboratory, University of Illinois, 104 South Goodwin, Urbana, Illinois 61801 and Thin Film Physics Division, Department of Physics (IFM), Linköping University, SE-58183 Linköping (Sweden)

    2013-11-15T23:59:59.000Z

    Single-crystal ZrN films, 830 nm thick, are grown on MgO(001) at 450 °C by magnetically unbalanced reactive magnetron sputtering. The combination of high-resolution x-ray diffraction reciprocal lattice maps, high-resolution cross-sectional transmission electron microscopy, and selected-area electron diffraction shows that ZrN grows epitaxially on MgO(001) with a cube-on-cube orientational relationship, (001){sub ZrN}?(001){sub MgO} and [100]{sub ZrN}?[100]{sub MgO}. The layers are essentially fully relaxed with a lattice parameter of 0.4575 nm, in good agreement with reported results for bulk ZrN crystals. X-ray reflectivity results reveal that the films are completely dense with smooth surfaces (roughness = 1.3 nm, consistent with atomic-force microscopy analyses). Based on temperature-dependent electronic transport measurements, epitaxial ZrN/MgO(001) layers have a room-temperature resistivity ?{sub 300K} of 12.0 ??-cm, a temperature coefficient of resistivity between 100 and 300 K of 5.6 × 10{sup ?8}?-cm K{sup ?1}, a residual resistivity ?{sub o} below 30 K of 0.78 ??-cm (corresponding to a residual resistivity ratio ?{sub 300?}/?{sub 15K} = 15), and the layers exhibit a superconducting transition temperature of 10.4 K. The relatively high residual resistivity ratio, combined with long in-plane and out-of-plane x-ray coherence lengths, ?{sub ?} = 18 nm and ?{sub ?} = 161 nm, indicates high crystalline quality with low mosaicity. The reflectance of ZrN(001), as determined by variable-angle spectroscopic ellipsometry, decreases slowly from 95% at 1 eV to 90% at 2 eV with a reflectance edge at 3.04 eV. Interband transitions dominate the dielectric response above 2 eV. The ZrN(001) nanoindentation hardness and modulus are 22.7 ± 1.7 and 450 ± 25 GPa.

  4. Am phases in the matrix of a U-Pu-Zr alloy with Np, Am, and rare-earth elements

    SciTech Connect (OSTI)

    Dawn E Janney; J. Rory Kennedy; James W. Madden; Thomas P. O'Holleran

    2015-01-01T23:59:59.000Z

    Phases and microstructures in the matrix of an as-cast U-Pu-Zr alloy with 3 wt% Am, 2% Np, and 8% rare-earth elements were characterized by scanning and transmission electron microscopy. The matrix consists primarily of two phases, both of which contain Am: ?-(U, Np, Pu, Am) (~70 at% U, 5% Np, 14% Pu, 1% Am, and 10% Zr) and ?-(U, Np, Pu, Am)Zr2 (~25% U, 2% Np, 10-15% Pu, 1-2% Am, and 55-60 at% Zr). These phases are similar to those in U-Pu-Zr alloys, although the Zr content in ?-(U, Np, Pu, Am) is higher than that in ?-(U, Pu) and the Zr content in ?-(U, Np, Pu, Am)Zr2 is lower than that in ?-UZr2. Nanocrystalline actinide oxides with structures similar to UO2 occurred in some areas, but may have formed by reactions with the atmosphere during sample handling. Planar features consisting of a central zone of ?-(U, Np, Pu, Am) bracketed by zones of ?-(U, Np, Pu, Am)Zr2 bound irregular polygons ranging in size from a few micrometers to a few tens of micrometers across. The rest of the matrix consists of elongated domains of ?-(U, Np, Pu, Am) and ?-(U, Np, Pu, Am)Zr2. Each of these domains is a few tens of nanometers across and a few hundred nanometers long. The domains display strong preferred orientations involving areas a few hundred nanometers to a few micrometers across.

  5. Diffusional Interaction between U – 10wt.% Zr and Fe at 903K, 923K and 953K

    SciTech Connect (OSTI)

    K Y. Park; K. Huang; A. Ewh; Y.H. Sohn; B. H. Sencer; J. R. Kennedy

    2015-01-01T23:59:59.000Z

    U-Zr metallic fuels cladded in Fe-alloys are being considered for application in an advanced Sodium-Cooled Fast Reactor (SFR) that can recycle the U-Zr fuels and minimize the long-lived actinide waste. To understand the complex fuel-cladding chemical interaction between the U-Zr metallic fuel with Fe-alloys, a systematic multicomponent diffusion study was carried out using solid-to-solid diffusion couples. The U-10 wt.% Zr vs. pure Fe diffusion couples were assembled and annealed at temperatures, 903, 923 and 953K for 96 hours. Development of microstructure, phase constituents, and compositions developed during the thermal anneals were examined by scanning electron microscopy, transmission electron microscopy and X-ray energy dispersive spectroscopy. Complex microstructure consisting of several layers that include phases such as U6Fe, UFe2, ZrFe2, alpha-U, betha-U, Zr-precipitates, ?, e and ? were observed. Multi-phase layers were grouped based on phase constituents and microstructure, and the layer thicknesses were measured to calculate the growth constant and activation energy. The local average compositions through the interaction layer were systematically determined, and employed to construct semi-quantitative diffusion paths on isothermal U-Zr-Fe ternary phase diagrams at respective temperatures. The diffusion paths were examined to qualitatively estimate the diffusional behavior of individual components and their interactions. Furthermore, selected area diffraction analyses were carried out to determine, for the first time, the exact crystal structure and composition of ?, e and ?-phases. The ?, e and ?-phases were identified as Pnma(62) Fe(Zr,U), I4/mcm(140) Fe(Zr,U)2, and I4/mcm(140) U3(Zr,Fe), respectively.

  6. Effect of thermal annealing on charge exchange between oxygen interstitial defects within HfO{sub 2} and oxygen-deficient silicon centers within the SiO{sub 2}/Si interface

    SciTech Connect (OSTI)

    Lauer, J. L.; Shohet, J. L. [Department of Electrical and Computer Engineering and Plasma Processing and Technology Laboratory, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States); Nishi, Y. [Stanford University, Stanford, California 94305 (United States)

    2009-04-20T23:59:59.000Z

    We compare the charging response of rapid thermally annealed (800 and 1000 deg. C) 4 nm thick HfO{sub 2} to as-deposited HfO{sub 2} on Si by measuring the surface potential of the HfO{sub 2} layers after vacuum ultraviolet (VUV) irradiation with 11.6 eV photons. From VUV spectroscopy, we determined all HfO{sub 2} layers show the presence of oxygen-interstitial defects (OIDs). The electronic states of OID in HfO{sub 2} line up in energy with oxygen-deficient Si centers within the SiO{sub 2} interfacial layer. This implies charge exchange between OIDs within HfO{sub 2} and the O-deficient silicon centers within the SiO{sub 2} interfacial layer are very important for controlling the radiation-induced trapped charge in HfO{sub 2} dielectric stacks.

  7. Modeling of Zircon (ZrSiO{sub 4}) and Zirconia (ZrO{sub 2}) using ADF-GUI Software

    SciTech Connect (OSTI)

    Lwin, Maung Tin Moe [Applied Radiation Laboratory, Department of Physics, Faculty of Science, University of Malaya, 50603 Kuala Lumpur (Malaysia); Amin, Yusoff Mohd; Kassim, Hasan Abu; Kamaluddin, Burhanuddin [Department of Physics, Faculty of Science, University of Malaya, 50603 Kuala Lumpur (Malaysia)

    2010-07-07T23:59:59.000Z

    Natural zircon (ZrSiO{sub 4}) has very high concentration of Uranium and Thorium of up to 5000 ppm. Radioactive decay process of alpha particles from these impurities affects some changes like several atomic displacements in the crystalline structure of zircon. The amount of track density caused by alpha particles decay process of these radioactive materials in zircon can be decreased with annealing temperatures from 700 deg. C to 980 deg. C. Recently it has been extensively studied as the possible candidate material for immobilization of fission products and actinides. Besides, zirconia (ZrO{sub 2}), product from natural zircon, is widely used in industrial field because it has excellent chemical and mechanical properties at high temperature. Dielectric constant of monoclinic, cubic and tetragonal ZrO{sub 2} can be found in the range of 22, 35 and 50 by computer simulation works. In recent years, atomistic simulations and modeling have been studied, because a lot of computational techniques can offer atomic-level approaching with minimum errors in estimations. One favorite methods is Density Functional Theory (DFT). In this study, ADF-GUI software from DFT will be used to calculate the frequency and absorption Intensity of zircon and zirconia molecules. The data from calculations will be verified with experimental works such as Raman Spectroscopy, AFM and XRD.

  8. Atomic scale observation of phase separation and formation of silicon clusters in Hf higk-{kappa} silicates

    SciTech Connect (OSTI)

    Talbot, E.; Roussel, M.; Genevois, C.; Pareige, P. [Groupe de Physique des Materiaux (GPM), Universite et INSA de Rouen, UMR CNRS 6634, Av. de l'Universite, BP 12, 76801 Saint Etienne du Rouvray (France); Khomenkova, L.; Portier, X.; Gourbilleau, F. [Centre de Recherche sur les Ions, les Materiaux et la Photonique (CIMAP), CEA/CNRS/ENSICAEN/UCBN, 6 Bd. Marechal Juin, 14050 Caen Cedex 4 (France)

    2012-05-15T23:59:59.000Z

    Hafnium silicate films were fabricated by RF reactive magnetron sputtering technique. Fine microstructural analyses of the films were performed by means of high-resolution transmission electron microscopy and atom probe tomography. A thermal treatment of as-grown homogeneous films leads to a phase separation process. The formation of SiO{sub 2} and HfO{sub 2} phases as well as pure Si one was revealed. This latter was found to be amorphous Si nanoclusters, distributed uniformly in the film volume. Their mean diameter and density were estimated to be about 2.8 nm and (2.9 {+-} 0.4) x 10{sup 17} Si-ncs/cm{sup 3}, respectively. The mechanism of the decomposition process was proposed. The obtained results pave the way for future microelectronic and photonic applications of Hf-based high-{kappa} dielectrics with embedded Si nanoclusters.

  9. Self-assembly of Ni nanocrystals on HfO{sub 2} and N-assisted Ni confinement for nonvolatile memory application

    SciTech Connect (OSTI)

    Tan, Zerlinda; Samanta, S.K.; Yoo, Won Jong; Lee, Sungjoo [Silicon Nano Device Laboratory, Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore 117576 (Singapore)

    2005-01-03T23:59:59.000Z

    We demonstrate memory property using Ni nanocrystals with mean diameter of 9 nm embedded in HfO{sub 2} high-k dielectric that are formed via a self-assembly process by sputtering and rapid thermal annealing. X-ray photoelectron spectroscopy shows that Ni penetrates into the 5 nm HfO{sub 2} after high temperature annealing above 800 deg. C in N{sub 2}. However, the diffusion is suppressed by N incorporation into HfO{sub 2} by NH{sub 3} annealing. Metal-oxide-semiconductor structures were fabricated with Ni nanocrystals embedded in HfO{sub 2}. An additional counterclockwise hysteresis of 2.1 V due to the charge trapping properties of the Ni nanocrystals was observed from a {+-}5 V sweep during capacitance-voltage electrical measurement.

  10. First in-beam observation of excited states in {sup 156}{sub 72}Hf{sub 84} using the recoul-decay tagging method

    SciTech Connect (OSTI)

    Seweryniak, D.; Ahmad, H.; Amro, D.J. [and others

    1996-12-31T23:59:59.000Z

    Excited states in the proton rich nuclide {sup 156}{sub 72}Hf{sub 84} were observed for the first time using the {sup 102}({sup 58}Ni, 2p2n){sup 156}Hf reaction at 270 MeV. Gamma rays were detected with the AYEBALL array of Compton suppressed Ge detectors, placed in front of the Fragment Mass Analyzer, and were assigned to individual reaction charmers using the Recoil-Decay Tagging Method. Prompt {gamma}-ray cascades were associated with the alpha decay of both the ground state and the 8{sup +} isomeric state in {sup 156}Hf. The level scheme constructed for {sup 156}Hf is compared with level schemes of lighter even-even N=84 isotones and is discussed within the framework of the Shell Model.

  11. Solvated Electrons in Very Small Clusters of Polar Molecules: (HF)(3)(-): art. no. 143001

    SciTech Connect (OSTI)

    Gutowski, Maciej S. (BATTELLE (PACIFIC NW LAB)); Hall, C (Arizona, University Of); Adamowicz, L (Arizona, University Of); Hendricks, J.H. (Johns Hopkins Univ); De Clercq, Helen (Howard University); Lyapustina, S.A. (Johns Hopkins Univ); Nilles, J.M. (Johns Hopkins Univ); Xu, S.J. (Johns Hopkins Univ); Bowen Jr., K.H. (Johns Hopkins Univ)

    2001-12-01T23:59:59.000Z

    A cluster of polar molecules can host an excess electron in at least two ways. First, the excess electron can be tethered to the cluster by its interaction with the cluster?s dipole moment. , Second, the electron can localize inside the cluster, bulk analogs being the hydrated and ammoniated electrons. - While the structural reorganization of the cluster, due to attachment of an excess electron, is typically small for dipole-bound electrons (dbe), it is usually quite significant for''solvated electrons'' (se), since the solvation occurs at the expense of breaking of pre-existing hydrogen bonds. The se structures, however, provide more contact interactions between the polar molecules and the excess electron. For these reasons, it is often assumed that dbe's dominate for small polar clusters, whereas large clusters form se's. Here we show that dbe's and se's coexist in as small a cluster as (HF)3-. The stability of these anions with respect to the neutral cluster results not only from the excess electron binding energy but also from favorable entropic effects, which reflect the greater ''floppiness'' of the anionic structures.

  12. Temperature dependent structural, optical and hydrophobic properties of sputtered deposited HfO{sub 2} films

    SciTech Connect (OSTI)

    Dave, V. [Department of Electrical Engineering, IIT Roorkee (India); Institute Instrumentation Centre, IIT Roorkee (India); Dubey, P.; Chandra, R. [Institute Instrumentation Centre, IIT Roorkee (India); Gupta, H. O. [Department of Electrical Engineering, IIT Roorkee (India)

    2014-01-28T23:59:59.000Z

    Hafnium oxide being high-k dielectric has been successfully utilized in electronic and optical applications. Being thermodynamically stable and having good mechanical strength, it can be used as a protective coating for outdoor HV insulators which are suffering from surface flashover problem due to contamination. In this paper, we are investigating the effect of substrate temperature on structural, optical and hydrophobic properties of hafnium oxide coating deposited over glass insulators by DC magnetron sputtering. X-ray diffraction is applied to determine the crystalline phase and crystallite size of the film. The morphology of the samples is examined using atomic force microscopy. The optical properties are studied using UV-vis-NIR spectrophotometer. The wettability of the film is investigated using contact angle meter. The thickness is measured using surface profilometer and verified through optical data. The relationship between substrate temperature with grain size, roughness, refractive index, and hydrophobicity is manifested. The maximum contact angle for HfO{sub 2} film was found to be 106° at 400°C.

  13. Complexity of shear localization in a Zr-based bulk metallic glass

    E-Print Network [OSTI]

    University of Aeronautics and Astronautics, Beijing 100191, China The compressive behaviour of a Zr. A significant advance occurred when compositions and copper mold casting method allowing for bulk material the consequence of) macroscopic shear banding remains unclear. It is therefore important to carry out in situ

  14. Complexity of shear localization in a Zr-based bulk metallic glass

    E-Print Network [OSTI]

    University of Aeronautics and Astronautics, Beijing 100191, China The compressive behaviour of a Zr. A significant advance occurred when compositions and copper mold casting method allowing for bulk material unclear. It is therefore important to carry out in situ observations of plastic deformation processes

  15. Stress-corrosion fatiguecrack growth in a Zr-based bulk amorphous metal

    E-Print Network [OSTI]

    Ritchie, Robert

    Stress-corrosion fatigue­crack growth in a Zr-based bulk amorphous metal V. Schroeder 1 , R metallic glass; Amorphous metal; Fatigue; Stress corrosion; Crack growth 1. Introduction In recent years­crack growth resistance [1­5], its corresponding properties in the presence of a corrosive environment have

  16. Phase Stability and Thermodynamic Assessment of the Np-Zr system

    E-Print Network [OSTI]

    Bajaj, Saurabh

    2012-02-14T23:59:59.000Z

    Metallic fuels have an important role to play in "fast breeder" Gen-IV type nuclear reactors, and U-Pu-Zr is one of the prototypical systems. Because of the variability in fuel chemistry during burn-up, it is important to understand the effect...

  17. Discovery of Critical Oxygen Content for Glass Formation in Zr80Pt20 Melt Spun Ribbons

    SciTech Connect (OSTI)

    D.J. Sordelet; E.A. Rozhkova; X. Yang; M.J. Kramer

    2004-09-30T23:59:59.000Z

    Zr{sub 80}Pt{sub 20} alloys may form meta-stable quasicrystals either during devitrification of an amorphous phase or directly upon cooling from a liquid depending on processing conditions. To date, little attention has been given to the role of oxygen on the glass formation or devitrification behavior of Zr-Pt and similar alloys. This study reveals that oxygen content during melt spinning indeed strongly influences the formation of the as-quenched structure. A critical amount of oxygen was found to be required to form amorphous ribbons at a fixed quench rate. At lower oxygen levels (i.e., <500 ppm mass), a fully crystallized is formed; the structure is composed mainly of meta-stable {beta}-Zr with a small fraction of a quasicrystalline phase. At higher oxygen levels, the as-quenched structure transitions to a fully amorphous structure ({approx}1000 ppm mass), and with further oxygen addition forms a mixture of amorphous and quasicrystalline ({approx}1500 ppm mass) or crystalline phases (>2500 ppm mass). Details regarding the structure of the meta-stable {beta}-Zr phase in the low-oxygen ribbons are provided along with a discussion of the structural similarity between this phase and the quasicrystal structure that formed in this alloy.

  18. Oxide Electronic Conductivity and Hydrogen Pickup Fraction in Zr alloys Adrien Coueta

    E-Print Network [OSTI]

    Motta, Arthur T.

    hydrogen ingress can cause cladding embrittlement and limit cladding lifetime. However, mechanisticOxide Electronic Conductivity and Hydrogen Pickup Fraction in Zr alloys Adrien Coueta , Arthur T, 77818 Moret-sur-Loing, France INTRODUCTION The hydrogen pick-up during cladding corrosion is a critical

  19. Chemical Synthesis of Pure and Gd-doped CaZrO3 Powders

    E-Print Network [OSTI]

    Tas, A. Cuneyt

    chemical synthesis techniques: (i) self-propagating combustion synthesis, and (ii) precipitation potential use as a high-temperature thermistor material.8 The electrical response of calcium zirconate (preChemical Synthesis of Pure and Gd-doped CaZrO3 Powders I. Erkin Gonenli a and A. CuÃ? neyt Tas b

  20. Thermoluminescence of ZrSiO4 (zircon): A new dating method?

    E-Print Network [OSTI]

    Donoghue, Joseph

    Thermoluminescence of ZrSiO4 (zircon): A new dating method? H.J. van Es a , D.I. Vainshtein a , A (TL) dating of sediments from the Quaternary. TL of zircon results predominantly from internal0168-583X(02)00627-4 #12;Heavily damaged grains significantly reduce the thermoluminescence (TL) light

  1. Defining the Proton Topology of the Zr6Based Metal-Organic Framework NU-1000

    E-Print Network [OSTI]

    ,16-19 heavy metal capture,20,21 sensing,12 ionic conductivity,22 toxic industrial chemical capture,23Defining the Proton Topology of the Zr6Based Metal-Organic Framework NU-1000 Nora Planas,, Joseph E of Science, King Abdulaziz University, Jeddah, Saudi Arabia *S Supporting Information ABSTRACT: Metal

  2. High temperature ablation resistance of ZrNp reinforced W matrix composites

    E-Print Network [OSTI]

    Hong, Soon Hyung

    modulus of elasticity, good thermal shock resistance, stiffness and good high temperature strengthHigh temperature ablation resistance of ZrNp reinforced W matrix composites Malik Adeel Umer microscopy (SEM) For the purpose of improving the high temperature ablation resistance of tungsten

  3. Features of the band structure and conduction mechanisms in the n-HfNiSn semiconductor heavily doped with Ru

    SciTech Connect (OSTI)

    Romaka, V. A., E-mail: vromaka@polynet.lviv.ua [National Academy of Sciences of Ukraine, Pidstrygach Institute for Applied Problems in Mechanics and Mathematics (Ukraine); Rogl, P. [Universität Wien, Institut für Physikalische Chemie (Austria); Romaka, V. V. [National University Lvivska Politekhnika (Ukraine); Stadnyk, Yu. V. [Ivan Franko National University of Lviv (Ukraine); Korzh, R. O.; Krayovskyy, V. Ya. [National University Lvivska Politekhnika (Ukraine); Horyn, A. M. [Ivan Franko National University of Lviv (Ukraine)

    2014-12-15T23:59:59.000Z

    The crystal and electronic structure and energy and kinetic properties of the n-HfNiSn semiconductor heavily doped with a Ru acceptor impurity are investigated in the temperature and Ru concentration ranges T = 80–400 K and N{sub A}{sup Ru} ? 9.5 × 10{sup 19}?5.7 × 10{sup 20} cm{sup ?3} (x = 0–0.03), respectively. The mechanism of structural-defect generation is established, which changes the band gap and degree of compensation of the semiconductor and consists in the simultaneous concentration reduction and elimination of donor structural defects by means of the displacement of ?1% of Ni atoms from the Hf (4a) positions, the generation of acceptor structural defects upon the substitution of Ru atoms for Ni atoms in the 4c positions, and the generation of donor defects in the form of vacancies in the Sn (4b) positions. The calculated electronic structure of HfNi{sub 1?x}Ru{sub x}Sn is consistent with the experiment. The results obtained are discussed within the Shklovsky-Efros model for a heavily doped and compensated semiconductor.

  4. Highly efficient dye-sensitized solar cells based on HfO{sub 2} modified TiO{sub 2} electrodes

    SciTech Connect (OSTI)

    Ramasamy, Parthiban [Department of Chemistry and GETRC, Kongju National University, 182 Singkwan, Kongju, Chungnam 314-701 (Korea, Republic of)] [Department of Chemistry and GETRC, Kongju National University, 182 Singkwan, Kongju, Chungnam 314-701 (Korea, Republic of); Kang, Moon-Sung; Cha, Hyeon-Jung [Department of Environmental Engineering, Sangmyung University, 300 Anseo-dong, Dongnam-gu, Cheonan-si, Chungnam 330-720 (Korea, Republic of)] [Department of Environmental Engineering, Sangmyung University, 300 Anseo-dong, Dongnam-gu, Cheonan-si, Chungnam 330-720 (Korea, Republic of); Kim, Jinkwon, E-mail: jkim@kongju.ac.kr [Department of Chemistry and GETRC, Kongju National University, 182 Singkwan, Kongju, Chungnam 314-701 (Korea, Republic of)] [Department of Chemistry and GETRC, Kongju National University, 182 Singkwan, Kongju, Chungnam 314-701 (Korea, Republic of)

    2013-01-15T23:59:59.000Z

    Graphical abstract: Display Omitted Highlights: ? HfO{sub 2} has been used to modify TiO{sub 2} electrodes in dye sensitized solar cells. ? HfO{sub 2} layer increases the dye adsorption. ? Diffusion coefficient (D{sub e}) and lifetime (?{sub e}) of the photoelectrons were increased. ? Solar cell efficiency (?) was greatly improved from 5.67 to 9.59%. -- Abstract: In this article, we describe the use of hafnium oxide (HfO{sub 2}) as a new and efficient blocking layer material to modify TiO{sub 2} electrodes in dye sensitized solar cells. Different thicknesses of HfO{sub 2} over-layers were prepared by simple dip coating from two different precursors and their effects on the performance of DSSCs were studied. The HfO{sub 2} modification remarkably increases dye adsorption, resulting from the fact that the surface of HfO{sub 2} is more basic than that of TiO{sub 2}. Furthermore, the HfO{sub 2} coating demonstrated increased diffusion coefficient (D{sub e}) and lifetime (?{sub e}) of the photoelectrons, indicating the improved retardation of the back electron transfer, which increases short-circuit current (J{sub sc}) and open-circuit voltage (V{sub oc}). Thereby, the photo conversion efficiency (?) of the solar cell was greatly improved from 5.67 to 9.59% (an improvement of 69.02%) as the HfO{sub 2} layer was coated over TiO{sub 2} films.

  5. Structure and dielectric properties of La{sub x}Hf{sub (1?x)}O{sub y} thin films: The dependence of components

    SciTech Connect (OSTI)

    Qi, Zeming, E-mail: zmqi@ustc.edu.cn [National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230029 (China); Cheng, Xuerui [Department of Technology and Physics, Zhengzhou University of Light Industry, Zhengzhou, Henan 450002 (China); Zhang, Guobin [National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230029 (China); Li, Tingting [Institute of Microelectronics of Chinese Academy of Science, Beijing 100029 (China); Wang, Yuyin; Shao, Tao; Li, Chengxiang; He, Bo [National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230029 (China)

    2013-07-15T23:59:59.000Z

    Graphical abstract: - Highlights: • La{sub x}Hf{sub (1?x)}O{sub y} thin films were grown by pulse laser deposition method. • The thin film with 10% La/(La + Hf) atom ratio forms a cubic HfO{sub 2} phase. • The amorphous thin films due to more La introduced have almost same local structure. • The main infrared phonon modes move to lower frequency for the amorphous thin films. • The static dielectric constants of the amorphous thin films increase with La content. - Abstract: La{sub x}Hf{sub (1?x)}O{sub y} (x = 0, 0.1, 0.3, 0.5, 0.7, y=2?(1/2)x) thin films were grown by pulsed laser deposition (PLD) method. The component dependence of the structure and vibration properties of these thin films is studied by combining X-ray diffraction, X-ray absorption fine structure (XAFS) and infrared spectroscopy. The thin film with 10% La/(La + Hf) atom ratio forms a cubic HfO{sub 2} phase and it has the largest static dielectric constant. More La atoms introduced cause amorphous phase formed and the static dielectric constants increase with the La content. Although XAFS indicates that these amorphous thin films have almost same local structures, the infrared phonon modes with most contribution to the static dielectric constant move to lower frequency, which results in the component dependence of the dielectric constant.

  6. Composition and grain size effects on the structural and mechanical properties of CuZr nanoglasses

    SciTech Connect (OSTI)

    Adibi, Sara [Institute of High Performance Computing, A*STAR, 138632 Singapore (Singapore); Mechanical Engineering Department, National University of Singapore, 117576 Singapore (Singapore); Branicio, Paulo S., E-mail: branicio@ihpc.a-star.edu.sg; Zhang, Yong-Wei [Institute of High Performance Computing, A*STAR, 138632 Singapore (Singapore); Joshi, Shailendra P., E-mail: Shailendra@nus.edu.sg [Mechanical Engineering Department, National University of Singapore, 117576 Singapore (Singapore)

    2014-07-28T23:59:59.000Z

    Nanoglasses (NGs), metallic glasses (MGs) with a nanoscale grain structure, have the potential to considerably increase the ductility of traditional MGs while retaining their outstanding mechanical properties. We investigated the effects of composition on the structural and mechanical properties of CuZr NG films with grain sizes between 3 to 15?nm using molecular dynamics simulations. Results indicate a transition from localized shear banding to homogeneous superplastic flow with decreasing grain size, although the critical average grain size depends on composition: 5?nm for Cu{sub 36}Zr{sub 64} and 3?nm for Cu{sub 64}Zr{sub 36}. The flow stress of the superplastic NG at different compositions follows the trend of the yield stress of the parent MG, i.e., Cu{sub 36}Zr{sub 64} yield/flow stress: 2.54?GPa/1.29?GPa and Cu{sub 64}Zr{sub 36} yield/flow stress: 3.57?GPa /1.58?GPa. Structural analysis indicates that the differences in mechanical behavior as a function of composition are rooted at the distinct statistics of prominent atomic Voronoi polyhedra. The mechanical behavior of NGs is also affected by the grain boundary thickness and the fraction of atoms at interfaces for a given average grain size. The results suggest that the composition dependence of the mechanical behavior of NGs follows that of their parent MGs, e.g., a stronger MG will generate a stronger NG, while the intrinsic tendency for homogeneous deformation occurring at small grain size is not affected by composition.

  7. Comment on `Update of 40K and 226Ra and 232Th series $\\gamma$-to-dose conversion factors for soil'

    E-Print Network [OSTI]

    Malins, Alex; Saito, Kimiaki

    2015-01-01T23:59:59.000Z

    A letter to the editor of the Journal of Environmental Radioactivity on the article: E. Gasser, A. Nachab, A. Nourreddine, Ch. Roy, and A. Sellam, `Update of 40K and 226Ra and 232Th series $\\gamma$-to-dose conversion factors for soil', J. Environ. Radioactiv. 138, 68-71 (2014), DOI: 10.1016/j.jenvrad.2014.08.002.

  8. Heating Greenhouses1 D.E. Buffington, R.A. Bucklin, R.W. Henley and D.B. McConnell2

    E-Print Network [OSTI]

    Watson, Craig A.

    AE11 Heating Greenhouses1 D.E. Buffington, R.A. Bucklin, R.W. Henley and D.B. McConnell2 1 supplemental heat is required. Obviously there are many ways this can be accomplished from the standpoint of these factors be considered when selecting and installing a heating system. HEATING SYSTEMS Greenhouse heating

  9. SPECIAL NOTES FOR NIH PROPOSALS--Postdocs Any NIH proposal requires an eRA Commons user name; request one at

    E-Print Network [OSTI]

    Bustamante, Carlos

    SPECIAL NOTES FOR NIH PROPOSALS--Postdocs Any NIH proposal requires an eRA Commons user name and the SF424 R &R guide (you can skip ahead to section I-32 of the latter) [http://grants1.nih://grants1.nih.gov/grants/funding/424/index.htm#inst If you have concerns about your visa status eligibility

  10. The integration of Human Factors (HF) in the SAR process training course text

    SciTech Connect (OSTI)

    Ryan, T.G.

    1995-03-01T23:59:59.000Z

    This text provides the technical basis for a two-day course on human factors (HF), as applied to the Safety Analysis Report (SAR) process. The overall objective of this text and course is to: provide the participant with a working knowledge of human factors-related requirements, suggestions for doing a human safety analysis applying a graded approach, and an ability to demonstrate using the results of the human safety analysis, that human factors elements as defined by DOE (human factors engineering, procedures, training, oversight, staffing, qualifications), can support wherever necessary, nuclear safety commitments in the SAR. More specifically, the objectives of the text and course are: (1) To provide the SAR preparer with general guidelines for doing HE within the context of a graded approach for the SAR; (2) To sensitize DOE facility managers and staff, safety analysts and SAR preparers, independent reviewers, and DOE reviewers and regulators, to DOE Order 5480.23 requirements for HE in the SAR; (3) To provide managers, analysts, reviewers and regulators with a working knowledge of HE concepts and techniques within the context of a graded approach for the SAR, and (4) To provide SAR managers and DOE reviewers and regulators with general guidelines for monitoring and coordinating the work of preparers of HE inputs throughout the SAR process, and for making decisions regarding the safety relevance of HE inputs to the SAR. As a ready reference for implementing the human factors requirements of DOE Order 5480.22 and DOE Standard 3009-94, this course text and accompanying two-day course are intended for all persons who are involved in the SAR.

  11. H.C. DORLAND, N.J. BEUKES, J. GUTZMER, D.A.D. EVANS AND R.A. ARMSTRONG SOUTH AFRICAN JOURNAL OF GEOLOGY, 2006, VOLUME 109 PAGE 139-156

    E-Print Network [OSTI]

    H.C. DORLAND, N.J. BEUKES, J. GUTZMER, D.A.D. EVANS AND R.A. ARMSTRONG SOUTH AFRICAN JOURNAL.evans@yale.edu R.A. Armstrong Research School of Earth Sciences, Australian National University, Canberra, Australia e-mail: Richard.Armstrong@anu.edu.au © 2006 March Geological Society of South Africa ABSTRACT

  12. Methane Combustion over Pd/ZrO2/SiC, Pd/CeO2/SiC, Pd/Zr0.5Ce0.5O2/SiC Catalysts

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    1 Methane Combustion over Pd/ZrO2/SiC, Pd/CeO2/SiC, Pd/Zr0.5Ce0.5O2/SiC Catalysts Xiaoning Guo a Laboratory of Coal Conversion, Institute of Coal Chemistry, Taiyuan 030001, PR China b GREMI UMR6606 CNRS0.5O2 solid solution) modified Pd/SiC catalysts for methane combustion are studied. XRD and XPS

  13. Ab initio investigation of phase stability of Y2Ti2O7 and Y2Zr2O7...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    to the defect-cotunnite state under high pressure. Citation: Xiao HY, F Gao, and WJ Weber.2009."Ab initio investigation of phase stability of Y2Ti2O7 and Y2Zr2O7 under high...

  14. Pressure Induced Structural Transformation in Gd2Ti2O7 and Gd2Zr2O7...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    in determining the pressure induced phase transformation. Citation: Xiao HY, and WJ Weber.2011."Pressure Induced Structural Transformation in Gd2Ti2O7 and Gd2Zr2O7."Journal of...

  15. Charge-trapping characteristics of fluorinated thin ZrO{sub 2} film for nonvolatile memory applications

    SciTech Connect (OSTI)

    Huang, X. D., E-mail: eexdhuang@gmail.com, E-mail: laip@eee.hku.hk [Key Laboratory of MEMS of the Ministry of Education, Southeast University, Nanjing 210096 (China); Shi, R. P.; Lai, P. T., E-mail: eexdhuang@gmail.com, E-mail: laip@eee.hku.hk [Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong (China)

    2014-04-21T23:59:59.000Z

    The effects of fluorine treatment on the charge-trapping characteristics of thin ZrO{sub 2} film are investigated by physical and electrical characterization techniques. The formation of silicate interlayer at the ZrO{sub 2}/SiO{sub 2} interface is effectively suppressed by fluorine passivation. However, excessive fluorine diffusion into the Si substrate deteriorates the quality of the SiO{sub 2}/Si interface. Compared with the ZrO{sub 2}-based memory devices with no or excessive fluorine treatment, the one with suitable fluorine-treatment time shows higher operating speed and better retention due to less resistance of built-in electric field (formed by trapped electrons) against electron injection from the substrate and smaller trap-assisted tunneling leakage, resulting from improved ZrO{sub 2}/SiO{sub 2} and SiO{sub 2}/Si interfaces.

  16. Thermal response of Ru electrodes in contact with SiO{sub 2} and Hf-based high-k gate dielectrics

    SciTech Connect (OSTI)

    Wen, H.-C.; Lysaght, P.; Alshareef, H.N.; Huffman, C.; Harris, H.R.; Choi, K.; Senzaki, Y.; Luan, H.; Majhi, P.; Lee, B.H.; Campin, M. J.; Foran, B.; Lian, G.D.; Kwong, D.-L. [SEMATECH, 2706 Montopolis Drive, Austin, Texas 78741(United States); University of Texas at Austin, Pickle Research Campus-Microelectronics and Engineering Research (PRC-MER) Building 2.606A/R9950, Austin, Texas 78712 (United States); SEMATECH, 2706 Montopolis Drive, Austin, Texas 78741 (United States); Advanced Technology Development Facility (ATDF) Inc., 2706 Montopolis Drive, Austin, Texas 78741 (United States); University of Texas at Austin, Pickle Research Campus-Microelectronics and Engineering Research (PRC-MER) Building 2.606A/R9950, Austin, Texas 78712 (United States)

    2005-08-15T23:59:59.000Z

    A systematic experimental evaluation of the thermal stability of Ru metal gate electrodes in direct contact with SiO{sub 2} and Hf-based dielectric layers was performed and correlated with electrical device measurements. The distinctly different interfacial reactions in the Ru/SiO{sub 2}, Ru/HfO{sub 2}, and Ru/HfSiO{sub x} film systems were observed through cross-sectional high-resolution transmission electron microscopy, high angle annular dark field scanning transmission electron microscopy with electron-energy-loss spectra, and energy dispersive x-ray spectra analysis. Ru interacted with SiO{sub 2}, but remained stable on HfO{sub 2} at 1000 deg. C. The onset of Ru/SiO{sub 2} interfacial interactions is identified via silicon substrate pitting possibly from Ru diffusion into the dielectric in samples exposed to a 900 deg. C/10-s anneal. The dependence of capacitor device degradation with decreasing SiO{sub 2} thickness suggests Ru diffuses through SiO{sub 2}, followed by an abrupt, rapid, nonuniform interaction of ruthenium silicide as Ru contacts the Si substrate. Local interdiffusion detected on Ru/HfSiO{sub x} samples may be due to phase separation of HfSiO{sub x} into HfO{sub 2} grains within a SiO{sub 2} matrix, suggesting that SiO{sub 2} provides a diffusion pathway for Ru. Detailed evidence consistent with a dual reaction mechanism for the Ru/SiO{sub 2} system at 1000 deg. C is presented.

  17. Electrochemical corrosion behavior of biomedical Ti22Nb and Ti22Nb6Zr alloys in saline medium

    E-Print Network [OSTI]

    Zheng, Yufeng

    Electrochemical corrosion behavior of biomedical Ti­22Nb and Ti­22Nb­6Zr alloys in saline medium B addition and potentiodynamic polarization on the microstructure and corrosion resistance of Ti­22Nb and Ti­22Nb­6Zr alloy samples.The corrosion tests were carried out in 0.9% NaCl at 37 8C and neutral p

  18. Devitrification kinetics and phase selection mechanisms in Cu-Zr metallic glasses

    SciTech Connect (OSTI)

    Kalay, Ilkay

    2010-12-15T23:59:59.000Z

    Metallic glasses have been a promising class of materials since their discovery in the 1960s. Indeed, remarkable chemical, mechanical and physical properties have attracted considerable attention, and several excellent reviews are available. Moreover, the special group of glass forming alloys known as the bulk metallic glasses (BMG) become amorphous solids even at relatively low cooling rates, allowing them to be cast in large cross sections, opening the scope of potential applications to include bulk forms and net shape structural applications. Recent studies have been reported for new bulk metallic glasses produced with lower cooling rates, from 0.1 to several hundred K/s. Some of the application products of BMGs include sporting goods, high performance springs and medical devices. Several rapid solidification techniques, including melt-spinning, atomization and surface melting have been developed to produce amorphous alloys. The aim of all these methods is to solidify the liquid phase rapidly enough to suppress the nucleation and growth of crystalline phases. Furthermore, the production of amorphous/crystalline composite (ACC) materials by partial crystallization of amorphous precursor has recently given rise to materials that provide better mechanical and magnetic properties than the monolithic amorphous or crystalline alloys. In addition, these advances illustrate the broad untapped potential of using the glassy state as an intermediate stage in the processing of new materials and nanostructures. These advances underlie the necessity of investigations on prediction and control of phase stability and microstructural dynamics during both solidification and devitrification processes. This research presented in this dissertation is mainly focused on Cu-Zr and Cu-Zr-Al alloy systems. The Cu-Zr binary system has high glass forming ability in a wide compositional range (35-70 at.% Cu). Thereby, Cu-Zr based alloys have attracted much attention according to fundamental research on the behaviors of glass forming alloys. Further motivation arising from the application of this system as a basis for many BMGs and ACC materials; the Cu-Zr system warrants this attention and offers great potential for the development of new materials. However, the prediction and control of microstructural evolution during devitrification remains challenging because of the complex devitrification behavior of the Cu-Zr binary alloy which is arising from the competition of metastable and stable phases and diversity of crystal structures. This dissertation details a systematic fundamental investigation into the mechanisms and kinetics of the various crystallization transformation processes involved in the overall devitrification response of Cu-Zr and Cu-Zr-Al glasses. Various isothermal and nonisothermal treatments are employed, and the structural response is characterized using bulk X-ray and thermal analysis methods as well as nanoscale microscopic analysis methods, revealing structural and chemical details down to the atomic-scale. By carefully combining techniques such as differential scanning calorimetry (DSC), in-situ synchrotron high energy X-ray diffraction (HEXRD), and transmission electron microscopy (TEM) to quantify the characterization transformations, this research has uncovered numerous details concerning the atomistic mechanisms of crystallization and has provided much new understanding related to the dominant phases, the overall reaction sequences, and the rate-controlling mechanisms. As such this work represents a substantial step forward in understanding these transformations and provides a clear framework for further progress toward ultimate application of controlled devitrification processing for the production of new materials with remarkable properties.

  19. DENSITY-FUNCTIONAL STUDY OF U-Mo AND U-Zr ALLOYS

    SciTech Connect (OSTI)

    Landa, A; Soderlind, P; Turchi, P A

    2010-11-01T23:59:59.000Z

    Density-functional theory previously used to describe phase equilibria in U-Zr alloys [A. Landa, P. Soederlind, P.E.A. Turchi, J. Alloys Comp. 478 (2009) 103-110] is extended to investigate the ground-state properties of U-Mo solid solutions. We discuss how the heat of formation in both alloys correlates with the charge transfer between the alloy components, and how the specific behavior of the density of states in the vicinity of the Fermi level promotes the stabilization of the U{sub 2}Mo compound. Our calculations prove that, due to the existence of a single {gamma}-phase over the typical fuel operation temperatures, {gamma}-U-Mo alloys should indeed have much lower constituent redistribution than {gamma}-U-Zr alloys for which binodal decomposition causes a high degree of constituent redistribution.

  20. Permeability of CoNbZr amorphous thin films over a wide frequency range

    SciTech Connect (OSTI)

    Koyama, H.; Tsujimoto, H.; Shirae, K.

    1987-09-01T23:59:59.000Z

    CoNbZr amorphous films have attracted the attention of many researchers because of their high saturation magnetization, high permeability, low coercivity, and nearly zero magnetostriction. For these films to be used, one of the important magnetic properties is the behavior of the permeability over a wide frequency range. We have measured the permeability of a square-shaped magnetic film (13 mm x 55 mm) sputtered on a glass substrate from 1 MHz to 400 MHz using a stripline. Over 400 MHz, the permeability of the magnetic film was measured using a ring-shaped sample mounted in a coaxial fixture. The wall motion permeability of CoNbZr amorphous films decreases from 1 kHz to nearly zero at 1 MHz. The rotation permeability is constant to 100 MHz and ferromagnetic resonance is observed near 1 GHz.

  1. Influence of multiphonon excitations and transfer on the fusion of Ca+Zr

    E-Print Network [OSTI]

    H. Esbensen; A. M. Stefanini

    2014-04-16T23:59:59.000Z

    Fusion data for $^{48}$Ca+$^{90,96}$Zr are analyzed by coupled-channels calculations that are based on the M3Y+repulsion, double-folding potential. By applying a previously determined nuclear density of $^{48}$Ca, the neutron densities of the zirconium isotopes are adjusted to optimize the fit to the fusion data, whereas the proton densities are determined by electron scattering experiments. It is shown that the fusion data can be explained fairly well by including couplings to one- and two-phonon excitations of the reacting nuclei and to one- and two-nucleon transfer reactions but there is also some sensitivity to multiphonon excitations. The neutron skin thicknesses extracted for the two zirconium isotopes are consistent with anti-proton measurements. The densities of the zirconium isotopes are used together with the previously determined nuclear density of $^{40}$Ca to calculate the M3Y+repulsion potentials and predict the fusion cross sections of $^{40}$Ca+$^{90,96}$Zr. The predicted cross sections for $^{40}$Ca+$^{90}$Zr are in reasonable agreement with the data when the influence of multiphonon excitations and a modest transfer is considered. The prediction of the $^{40}$Ca+$^{96}$Zr fusion cross section, on the other hand, is poor and under-predicts the data by 30 to 40%. Although couplings to transfer channels with positive $Q$ values were expected to play an important role, they are not able to explain the data, primarily because the predicted Coulomb barrier is about 1.5 MeV too high. Possible reasons for this failure are discussed.

  2. Transient phenomena in the dielectric breakdown of HfO{sub 2} optical films probed by ultrafast laser pulse pairs

    SciTech Connect (OSTI)

    Nguyen, Duy N.; Emmert, Luke A.; Rudolph, Wolfgang [Department of Physics and Astronomy, University of New Mexico, Albuquerque, New Mexico 87131 (United States); Patel, Dinesh; Menoni, Carmen S. [Department of Electrical and Computer Engineering, Colorado State University, Fort Collins, Colorado 80523 (United States)

    2010-11-08T23:59:59.000Z

    The laser induced breakdown threshold of HfO{sub 2} films is studied with single pairs of pulses of variable delay and 50 fs and 1 ps pulse duration. Two distinct transient regimes are observed that can be related to the relaxation of the electron density from the conduction band via an intermediate state to the valence band. The experimental results are in good agreement with a theoretical model that assumes occupation of mid gap states after the first pulse on a time scale of several tens of picoseconds and subsequent decay of this population via recombination with holes in the valence band on a time scale of several tens of milliseconds.

  3. Controlled oxygen vacancy induced p-type conductivity in HfO{sub 2-x} thin films

    SciTech Connect (OSTI)

    Hildebrandt, Erwin; Kurian, Jose; Mueller, Mathis M.; Kleebe, Hans-Joachim; Alff, Lambert [Institute of Materials Science, Technische Universitaet Darmstadt, 64287 Darmstadt (Germany); Schroeder, Thomas [IHP, 15236 Frankfurt/Oder (Germany)

    2011-09-12T23:59:59.000Z

    We have synthesized highly oxygen deficient HfO{sub 2-x} thin films by controlled oxygen engineering using reactive molecular beam epitaxy. Above a threshold value of oxygen vacancies, p-type conductivity sets in with up to 6 times 10{sup 21} charge carriers per cm{sup 3}. At the same time, the band-gap is reduced continuously by more than 1 eV. We suggest an oxygen vacancy induced p-type defect band as origin of the observed behavior.

  4. Room temperature strain rate sensitivity in precursor derived HfO{sub 2}/Si-C-N(O) ceramic nanocomposites

    SciTech Connect (OSTI)

    Sujith, Ravindran; Kumar, Ravi, E-mail: nvrk@iitm.ac.in [Materials Processing Section, Department of Metallurgical and Materials Engineering, Indian Institute of Technology Madras, Chennai-600036, India. (India)] [Materials Processing Section, Department of Metallurgical and Materials Engineering, Indian Institute of Technology Madras, Chennai-600036, India. (India)

    2014-01-15T23:59:59.000Z

    Investigation on the room temperature strain rate sensitivity using depth sensing nanoindentation is carried out on precursor derived HfO{sub 2}/Si-C-N(O) ceramic nanocomposite sintered using pulsed electric current sintering. Using constant load method the strain rate sensitivity values are estimated. Lower strain rate sensitivity of ? 3.7 × 10{sup ?3} is observed and the limited strain rate sensitivity of these ceramic nanocomposites is explained in terms of cluster model. It is concluded that presence of amorphous Si-C-N(O) clusters are responsible for the limited flowability in these ceramics.

  5. Physical properties and band structure of reactive molecular beam epitaxy grown oxygen engineered HfO{sub 2{+-}x}

    SciTech Connect (OSTI)

    Hildebrandt, Erwin; Kurian, Jose; Alff, Lambert [Institute of Materials Science, Technische Universitaet Darmstadt, 64287 Darmstadt (Germany)

    2012-12-01T23:59:59.000Z

    We have conducted a detailed thin film growth structure of oxygen engineered monoclinic HfO{sub 2{+-}x} grown by reactive molecular beam epitaxy. The oxidation conditions induce a switching between (111) and (002) texture of hafnium oxide. The band gap of oxygen deficient hafnia decreases with increasing amount of oxygen vacancies by more than 1 eV. For high oxygen vacancy concentrations, defect bands form inside the band gap that induce optical transitions and p-type conductivity. The resistivity changes by several orders of magnitude as a function of oxidation conditions. Oxygen vacancies do not give rise to ferromagnetic behavior.

  6. Investigations of the g{sub K}-factors in the {sup 175,177,179}Hf Isotopes

    SciTech Connect (OSTI)

    Yakut, Hakan; Kuliev, Ali [Sakarya University, Department of physics, Sakarya (Turkey); Guliyev, Ekber [National Academy of Sciences, Institute of Physics, Baku (Azerbaijan)

    2008-11-11T23:59:59.000Z

    In this paper the intrinsic g{sub K} and effective spin g{sub s} factors of the odd-mass {sup 175-179}Hf isotopes have been investigated within the Tamm-Dancoff approximation by using the realistic Saxon-Woods potential. The theoretically calculated g{sub K} and g{sub s}{sup eff} values are compared with experimental data. The comparison of the measured and calculated values of the effective g{sub s} factor shows that the spin polarization explains quite well the observed reduction of g{sub s} from its free-nucleon value.

  7. Energy band alignment of atomic layer deposited HfO{sub 2} on epitaxial (110)Ge grown by molecular beam epitaxy

    SciTech Connect (OSTI)

    Hudait, M. K.; Zhu, Y. [Bradley Department of Electrical and Computer Engineering, Virginia Tech, Blacksburg, Virginia 24061 (United States)] [Bradley Department of Electrical and Computer Engineering, Virginia Tech, Blacksburg, Virginia 24061 (United States); Maurya, D.; Priya, S. [Center for Energy Harvesting Materials and Systems (CEHMS), Virginia Tech, Blacksburg, Virginia 24061 (United States)] [Center for Energy Harvesting Materials and Systems (CEHMS), Virginia Tech, Blacksburg, Virginia 24061 (United States)

    2013-03-04T23:59:59.000Z

    The band alignment properties of atomic layer HfO{sub 2} film deposited on epitaxial (110)Ge, grown by molecular beam epitaxy, was investigated using x-ray photoelectron spectroscopy. The cross-sectional transmission electron microscopy exhibited a sharp interface between the (110)Ge epilayer and the HfO{sub 2} film. The measured valence band offset value of HfO{sub 2} relative to (110)Ge was 2.28 {+-} 0.05 eV. The extracted conduction band offset value was 2.66 {+-} 0.1 eV using the bandgaps of HfO{sub 2} of 5.61 eV and Ge bandgap of 0.67 eV. These band offset parameters and the interface chemical properties of HfO{sub 2}/(110)Ge system are of tremendous importance for the design of future high hole mobility and low-power Ge-based metal-oxide transistor devices.

  8. Photo-induced tunneling currents in MOS structures with various HfO{sub 2}/SiO{sub 2} stacking dielectrics

    SciTech Connect (OSTI)

    Pang, Chin-Sheng; Hwu, Jenn-Gwo, E-mail: jghwu@ntu.edu.tw [Graduate Institute of Electronics Engineering/Department of Electrical Engineering, National Taiwan University, Taipei, 10617, Taiwan (China)] [Graduate Institute of Electronics Engineering/Department of Electrical Engineering, National Taiwan University, Taipei, 10617, Taiwan (China)

    2014-04-15T23:59:59.000Z

    In this study, the current conduction mechanisms of structures with tandem high-k dielectric in illumination are discussed. Samples of Al/SiO{sub 2}/Si (S), Al/HfO{sub 2}/SiO{sub 2}/Si (H), and Al/3HfO{sub 2}/SiO{sub 2}/Si (3H) were examined. The significant observation of electron traps of sample H compares to sample S is found under the double bias capacitance-voltage (C-V) measurements in illumination. Moreover, the photo absorption sensitivity of sample H is higher than S due to the formation of HfO{sub 2} dielectric layer, which leads to larger numbers of carriers crowded through the sweep of V{sub G} before the domination of tunneling current. Additionally, the HfO{sub 2} dielectric layer would block the electrons passing through oxide from valance band, which would result in less electron-hole (e{sup ?}-h{sup +}) pairs recombination effect. Also, it was found that both of the samples S and H show perimeter dependency of positive bias currents due to strong fringing field effect in dark and illumination; while sample 3H shows area dependency of positive bias currents in strong illumination. The non-uniform tunneling current through thin dielectric and through HfO{sub 2} stacking layers are importance to MOS(p) tunneling photo diodes.

  9. Searches for HCl and HF in comets 103P/Hartley 2 and C/2009 P1 (Garradd) with the Herschel space observatory

    E-Print Network [OSTI]

    Bockelée-Morvan, D; Crovisier, J; Lis, D C; Hartogh, P; Moreno, R; de Val-Borro, M; Blake, G A; Szutowicz, S; Boissier, J; Cernicharo, J; Charnley, S B; Combi, M; Cordiner, M A; de Graauw, T; Encrenaz, P; Kidger, M; Küppers, M; Milam, S N; Müller, H S P; Phillips, T G; Rengel, M

    2014-01-01T23:59:59.000Z

    HCl and HF are expected to be the main reservoirs of fluorine and chlorine wherever hydrogen is predominantly molecular. They are found to be strongly depleted in dense molecular clouds, suggesting freeze-out onto grains in such cold environments. We can then expect that HCl and HF were also the major carriers of Cl and F in the gas and icy phases of the outer solar nebula, and were incorporated into comets. We aimed to measure the HCl and HF abundances in cometary ices as they can provide insights on the halogen chemistry in the early solar nebula. We searched for the J(1-0) lines of HCl and HF at 626 and 1232 GHz, respectively, using the HIFI instrument on board the Herschel Space Observatory. HCl was searched for in comets 103P/Hartley 2 and C/2009 P1 (Garradd), whereas observations of HF were conducted in comet C/2009 P1. In addition, observations of H$_2$O and H$_2^{18}$O lines were performed in C/2009 P1 to measure the H$_2$O production rate. Three lines of CH$_3$OH were serendipitously observed in the ...

  10. A Novel Zr-1Nb Alloy and a New Look at Hydriding

    SciTech Connect (OSTI)

    Robert D. Mariani; James I. Cole; Assel Aitkaliyeva

    2013-09-01T23:59:59.000Z

    A novel Zr-1Nb has begun development based on a working model that takes into account the hydrogen permeabilities for zirconium and niobium metals. The beta-Nb secondary phase particles (SPPs) in Zr-1Nb are believed to promote more rapid hydrogen dynamics in the alloy in comparison to other zirconium alloys. Furthermore, some hydrogen release is expected at the lower temperatures corresponding to outages when the partial pressure of H2 in the coolant is less. These characteristics lessen the negative synergism between corrosion and hydriding that is otherwise observed in cladding alloys without niobium. In accord with the working model, development of nanoscale precursors was initiated to enhance the performance of existing Zr-1Nb alloys. Their characteristics and properties can be compared to oxide-dispersion strengthened alloys, and material additions have been proposed to zirconium-based LWR cladding to guard further against hydriding and to fix the size of the SPPs for microstructure stability enhancements. A preparative route is being investigated that does not require mechanical alloying, and 10 nanometer molybdenum particles have been prepared which are part of the nanoscale precursors. If successful, the approach has implications for long term dry storage of used fuel and for new routes to nanoferritic and ODS alloys.

  11. Electrical characteristics and thermal stability of HfO{sub 2} metal-oxide-semiconductor capacitors fabricated on clean reconstructed GaSb surfaces

    SciTech Connect (OSTI)

    Miyata, Noriyuki, E-mail: nori.miyata@aist.go.jp; Mori, Takahiro; Yasuda, Tetsuji [National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8568 (Japan); Ohtake, Akihiro [National Institute for Materials Science (NIMS), Tsukuba, Ibaraki 305-0044 (Japan); Ichikawa, Masakazu [The University of Tokyo, Tokyo 113-8656 (Japan)

    2014-06-09T23:59:59.000Z

    HfO{sub 2}/GaSb interfaces fabricated by high-vacuum HfO{sub 2} deposition on clean reconstructed GaSb surfaces were examined to explore a thermally stable GaSb metal-oxide-semiconductor structure with low interface-state density (D{sub it}). Interface Sb-O bonds were electrically and thermally unstable, and post-metallization annealing at temperatures higher than 200?°C was required to stabilize the HfO{sub 2}/GaSb interfaces. However, the annealing led to large D{sub it} in the upper-half band gap. We propose that the decomposition products that are associated with elemental Sb atoms act as interface states, since a clear correlation between the D{sub it} and the Sb coverage on the initial GaSb surfaces was observed.

  12. Effect of nitrogen incorporation on improvement of leakage properties in high-k HfO{sub 2} capacitors treated by N{sub 2}-plasma

    SciTech Connect (OSTI)

    Seong, Nak-Jin; Yoon, Soon-Gil; Yeom, Seung-Jin; Woo, Hyun-Kyung; Kil, Deok-Sin; Roh, Jae-Sung; Sohn, Hyun-Chul [Department of Materials Science and Engineering, Chungnam National University, Daeduk Science Town, 305-764, Daejon (Korea, Republic of); Hynix Semiconductor Inc., San 136-1 Ami-ri Bubal-eub Icheon-si Kyoungki-do, 467-701 (Korea, Republic of)

    2005-09-26T23:59:59.000Z

    The nitrogen incorporation into the HfO{sub 2} films with an EOT (equivalent oxide thickness) of 9 A was performed by N{sub 2}-plasma to improve the electrical properties. The dielectric properties and a leakage current characteristics of the capacitors were investigated as a function of plasma power and plasma treatment temperature. The dielectric constant of the capacitors is not influenced by nitrogen incorporation. The N{sub 2}-plasma treatment at 300 deg. C and 70 W exhibits the most effective influence on improvement of the leakage current characteristics. Leakage current density of the capacitors treated at 300 deg. C and 70 W exhibits a half order of magnitude lower than that without plasma treatment. Nitrogen incorporated into the HfO{sub 2} films possesses the intrinsic effect that drastically reduce the electron leakage current through HfO{sub 2} dielectrics by deactivating the V{sub O} (oxygen vacancy) related gap states.

  13. Demonstrating 1 nm-oxide-equivalent-thickness HfO{sub 2}/InSb structure with unpinning Fermi level and low gate leakage current density

    SciTech Connect (OSTI)

    Trinh, Hai-Dang [Department of Materials Science and Engineering, National Chiao Tung University, 1001 University Road, Hsinchu, Taiwan (China) [Department of Materials Science and Engineering, National Chiao Tung University, 1001 University Road, Hsinchu, Taiwan (China); Department of Physics, Hanoi National University of Education, 136 Xuan Thuy, Cau Giay, Hanoi (Viet Nam); Lin, Yueh-Chin; Nguyen, Hong-Quan; Luc, Quang-Ho [Department of Materials Science and Engineering, National Chiao Tung University, 1001 University Road, Hsinchu, Taiwan (China)] [Department of Materials Science and Engineering, National Chiao Tung University, 1001 University Road, Hsinchu, Taiwan (China); Nguyen, Minh-Thuy; Duong, Quoc-Van; Nguyen, Manh-Nghia [Department of Physics, Hanoi National University of Education, 136 Xuan Thuy, Cau Giay, Hanoi (Viet Nam)] [Department of Physics, Hanoi National University of Education, 136 Xuan Thuy, Cau Giay, Hanoi (Viet Nam); Wang, Shin-Yuan [Department of Electronic Engineering, National Chiao Tung University 1001, University Rd., Hsinchu 300, Taiwan (China)] [Department of Electronic Engineering, National Chiao Tung University 1001, University Rd., Hsinchu 300, Taiwan (China); Yi Chang, Edward [Department of Materials Science and Engineering, National Chiao Tung University, 1001 University Road, Hsinchu, Taiwan (China) [Department of Materials Science and Engineering, National Chiao Tung University, 1001 University Road, Hsinchu, Taiwan (China); Department of Electronic Engineering, National Chiao Tung University 1001, University Rd., Hsinchu 300, Taiwan (China)

    2013-09-30T23:59:59.000Z

    In this work, the band alignment, interface, and electrical characteristics of HfO{sub 2}/InSb metal-oxide-semiconductor structure have been investigated. By using x-ray photoelectron spectroscopy analysis, the conduction band offset of 1.78 ± 0.1 eV and valence band offset of 3.35 ± 0.1 eV have been extracted. The transmission electron microscopy analysis has shown that HfO{sub 2} layer would be a good diffusion barrier for InSb. As a result, 1 nm equivalent-oxide-thickness in the 4 nm HfO{sub 2}/InSb structure has been demonstrated with unpinning Fermi level and low leakage current of 10{sup ?4} A/cm{sup ?2}. The D{sub it} value of smaller than 10{sup 12} eV{sup ?1}cm{sup ?2} has been obtained using conduction method.

  14. Band alignment and interfacial structure of ZnO/Si heterojunction with Al{sub 2}O{sub 3} and HfO{sub 2} as interlayers

    SciTech Connect (OSTI)

    Lu, Hong-Liang, E-mail: honglianglu@fudan.edu.cn; Yang, Ming; Xie, Zhang-Yi; Geng, Yang; Zhang, Yuan; Wang, Peng-Fei; Sun, Qing-Qing; Ding, Shi-Jin; Wei Zhang, David [State Key Laboratory of ASIC and System, Institute of Advanced Nanodevices, School of Microelectronics, Fudan University, Shanghai 200433 (China)

    2014-04-21T23:59:59.000Z

    Energy band alignment of ZnO/Si heterojunction with thin interlayers Al{sub 2}O{sub 3} and HfO{sub 2} grown by atomic layer deposition has been studied using x-ray photoelectron spectroscopy. The valence band offsets of ZnO/Al{sub 2}O{sub 3} and ZnO/HfO{sub 2} heterojunctions have been determined to be 0.43 and 0.22?eV, respectively. Accordingly, the band alignment ZnO/Si heterojunction is then modified to be 0.34 and 0.50?eV through inserting a thin Al{sub 2}O{sub 3} and HfO{sub 2} layer, respectively. The feasibility to tune the band structure of ZnO/Si heterojunction by selecting a proper interlayer shows great advantage in improving the performance of the ZnO-based optoelectronic devices.

  15. Thickness-modulated optical dielectric constants and band alignments of HfO{sub x}N{sub y} gate dielectrics

    SciTech Connect (OSTI)

    He, G.; Zhang, L. D.; Liu, M.; Zhang, J. P.; Wang, X. J. [Key Laboratory of Materials Physics, Anhui Key Laboratory of Nanomaterials and Nanostructure, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031 (China); Zhen, C. M. [Department of Physics, Hebei Advanced Thin Films Laboratory, Hebei Normal University, Shijiazhuang 050016 (China)

    2009-01-01T23:59:59.000Z

    Thickness-modulated optical dielectric constants and band alignments of HfO{sub x}N{sub y} films grown by sputtering have been investigated by spectroscopic ellipsometry (SE) and x-ray photoelectron spectroscopy. Based on SE measurements, it has been noted that an increase in optical dielectric constant and band gap has been observed as a function of the film thickness. Analyses of thickness-dependent band alignment of the HfO{sub x}N{sub y}/Si system indicate that the valence band offset increases, but only slight change in the conduction band offset, resulting from the thickness-induced change in the structure. The suitable optical dielectric constants and band offsets relative to Si make sputtering-derived HfO{sub x}N{sub y} film a promising candidate for high-k gate dielectrics.

  16. Influence of trimethylaluminum on the growth and properties of HfO{sub 2}/In{sub 0.53}Ga{sub 0.47}As interfaces

    SciTech Connect (OSTI)

    Hwang, Yoontae; Stemmer, Susanne [Materials Department, University of California, Santa Barbara, California 93106-5050 (United States); Engel-Herbert, Roman [Department of Materials Science and Engineering, Pennsylvania State University, University Park Pennsylvania 16802 (United States)

    2011-01-31T23:59:59.000Z

    The growth and the electrical properties of HfO{sub 2}/In{sub 0.53}Ga{sub 0.47}As interfaces are characterized as a function of exposure to trimethylaluminum (TMA) prior to chemical beam deposition of HfO{sub 2} from an alkoxide precursor. It is shown that TMA can act as a surfactant for HfO{sub 2} growth for (2x4) but not for the group-III-rich (4x2) reconstructed surfaces. The Fermi-level can be unpinned by postdeposition forming gas anneals only for interfaces that were exposed to low doses of TMA at low temperatures. The results are discussed in the context of the interaction between TMA and III-V surfaces.

  17. The effect of nanocrystallite size in monoclinic HfO{sub 2} films on lattice expansion and near-edge optical absorption

    SciTech Connect (OSTI)

    Cisneros-Morales, M. C.; Aita, C. R. [Department of Chemistry and Biochemistry and the Advanced Coatings Experimental Laboratory, University of Wisconsin-Milwaukee, P.O. Box 413, Milwaukee, Wisconsin 53201 (United States)

    2010-05-10T23:59:59.000Z

    Nanocrystalline monoclinic HfO{sub 2} films were sputter deposited on fused silica substrates, air annealed at 573 to 1273 K to affect crystallite growth, and analyzed by x-ray diffraction and spectrophotometry. Lattice expansion occurs with diminishing crystallite size. O 2p->Hf 5d interband absorption dominates the optical edge at energy E>=6.24 eV, with an optical band gap, E{sub o}=5.48+-0.023, which is independent of crystallite size. However, the strength of a localized resonant band, with onset at 5.65 eV and maximum at 5.94 eV, is affected by crystallite size. Its polaronic origin in a perfect HfO{sub 2} lattice is discussed.

  18. In situ photoemission spectroscopy study on formation of HfO{sub 2} dielectrics on epitaxial graphene on SiC substrate

    SciTech Connect (OSTI)

    Chen, Q.; Huang, H.; Chen, W.; Wee, A. T. S.; Feng, Y. P. [Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542 (Singapore); Chai, J. W.; Zhang, Z.; Pan, J. S.; Wang, S. J. [Institute of Materials Research and Engineering, A-STAR (Agency for Science, Technology, and Research), 3 Research Link, Singapore 117602 (Singapore)

    2010-02-15T23:59:59.000Z

    High quality HfO{sub 2} dielectrics have been grown on epitaxial graphene on 4H-SiC substrates and have been studied by using in situ x-ray photoemission spectroscopy. The in situ thermal treatment shows that the HfO{sub 2}/graphene/4H-SiC heterojunctions have good thermal stability up to 650 deg. C. A shift of core-level spectra from graphene layer implies that charge transfer takes place at the interface. The high thermal stability and sufficient barrier heights between HfO{sub 2} and graphene indicate that high-k dielectric grown on graphene is very promising for the development of graphene-based electronic devices.

  19. Fluorohydrogenate Cluster Ions in the Gas Phase: Electrospray Ionization Mass Spectrometry of the [1-Ethyl-3-methylimidazolium+][F(HF)2.3–] Ionic Liquid

    SciTech Connect (OSTI)

    Gary S. Groenewold; James E. Delmore; Michael T. Benson; Tetsuya Tsuda; Rika Hagiwara

    2013-12-01T23:59:59.000Z

    Electrospray ionization of the fluorohydrogenate ionic liquid [1-ethyl-3-methylimidazolium][F(HF)2.3] ionic liquid was conducted to understand the nature of the anionic species as they exist in the gas phase. Abundant fluorohydrogenate clusters were produced; however, the dominant anion in the clusters was [FHF-], and not the fluoride-bound HF dimers or trimers that are seen in solution. Density functional theory (DFT) calculations suggest that HF molecules are bound to the clusters by about 30 kcal/mol. The DFT-calculated structures of the [FHF-]-bearing clusters show that the favored interactions of the anions are with the methynic and acetylenic hydrogen atoms on the imidazolium cation, forming planar structures similar to those observed in the solid state. A second series of abundant negative ions was also formed that contained [SiF5-] together with the imidazolium cation and the fluorohydrogenate anions that originate from reaction of the spray solution with silicate surfaces.

  20. RE/ZrO{sub 2} (RE = Sm, Eu) composite oxide nano-materials: Synthesis and applications in photocatalysis

    SciTech Connect (OSTI)

    Du, Weimin, E-mail: duweimin75@gmail.com [College of Chemistry and Chemical Engineering, Anyang Normal University, Anyang, Henan 455002 (China); Zhu, Zhaoqiang [College of Chemistry and Chemical Engineering, Anyang Normal University, Anyang, Henan 455002 (China); College of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou, Henan 450001 (China); Zhang, Xiaofen; Wang, Dacheng; Liu, Donghe [College of Chemistry and Chemical Engineering, Anyang Normal University, Anyang, Henan 455002 (China); Qian, Xuefeng [School of Chemistry and Chemical Technology, Shanghai Jiao Tong University, Shanghai 200240 (China); Du, Jimin, E-mail: djm@aynu.edu.cn [College of Chemistry and Chemical Engineering, Anyang Normal University, Anyang, Henan 455002 (China)

    2013-10-15T23:59:59.000Z

    Graphical abstract: - Highlights: • RE/ZrO{sub 2} (RE = Sm, Eu) nano-materials have been successfully synthesized. • Defect and electron structures determine the absorption properties on visible light. • Nano-sized Zr{sub 0.8}Sm{sub 0.2}O{sub 2??} has good visible-light-responsive photocatalytic activities. • In the future, it can be used in wastewater treatment and environmental protection. - Abstract: Zirconia modified by Samarium/Europium, RE/ZrO{sub 2} (RE = Sm, Eu), composite oxide nano-materials have been successfully synthesized by improved sol–gel method. Characterization results show that X-ray diffraction (XRD) peaks of products gradually shift to the lower angle with the increase of rare earth which implies that the lattice distances of RE/ZrO{sub 2} nano-materials are gradually enlarged. Moreover, the molar ratios between zirconium and rare earth are consistent with the chemical formula and both of them are uniformly distributed in samples. Optical properties indicate that defect structures and electron configurations of RE/ZrO{sub 2} (RE = Sm, Eu) with single phase determine their absorption properties on visible light. Photocatalytic experiments indicate Zr{sub 0.8}Sm{sub 0.2}O{sub 2??} nano-crystals have excellent visible-light-responsive photocatalytic activities on Methylene blue and Rhodamine B which results from the special defect structure, suitable electronic configuration, and larger specific surface area. It follows that Zr{sub 0.8}Sm{sub 0.2}O{sub 2??} nano-crystals are new visible-light-responsive photocatalysts which can be applied in dye wastewater treatment and environmental protection in the future.

  1. Self-organization during growth of ZrN/SiN{sub x} multilayers by epitaxial lateral overgrowth

    SciTech Connect (OSTI)

    Fallqvist, A.; Fager, H.; Hultman, L.; Persson, P. O. Å. [Thin Film Physics Division, Department of Physics, Chemistry and Biology (IFM), Linköping University, SE-581 83 Linköping (Sweden)] [Thin Film Physics Division, Department of Physics, Chemistry and Biology (IFM), Linköping University, SE-581 83 Linköping (Sweden); Ghafoor, N. [Nanostructured Materials, Department of Physics, Chemistry and Biology (IFM), Linköping University, SE-581 83 Linköping (Sweden)] [Nanostructured Materials, Department of Physics, Chemistry and Biology (IFM), Linköping University, SE-581 83 Linköping (Sweden)

    2013-12-14T23:59:59.000Z

    ZrN/SiN{sub x} nanoscale multilayers were deposited on ZrN seed layers grown on top of MgO(001) substrates by dc magnetron sputtering with a constant ZrN thickness of 40 Å and with an intended SiN{sub x} thickness of 2, 4, 6, 8, and 15 Å at a substrate temperature of 800 °C and 6 Å at 500 °C. The films were investigated by X-ray diffraction, high-resolution scanning transmission electron microscopy, and energy dispersive X-ray spectroscopy. The investigations show that the SiN{sub x} is amorphous and that the ZrN layers are crystalline. Growth of epitaxial cubic SiN{sub x}—known to take place on TiN(001)—on ZrN(001) is excluded to the monolayer resolution of this study. During the course of SiN{sub x} deposition, the material segregates to form surface precipitates in discontinuous layers for SiN{sub x} thicknesses ?6 Å that coalesce into continuous layers for 8 and 15 Å thickness at 800 °C, and for 6 Å at 500 °C. The SiN{sub x} precipitates are aligned vertically. The ZrN layers in turn grow by epitaxial lateral overgrowth on the discontinuous SiN{sub x} in samples deposited at 800 °C with up to 6 Å thick SiN{sub x} layers. Effectively a self-organized nanostructure can be grown consisting of strings of 1–3 nm large SiN{sub x} precipitates along apparent column boundaries in the epitaxial ZrN.

  2. Synthesis and crystal structure of CuZrTiO{sub 5}-A new crystal structure type

    SciTech Connect (OSTI)

    Troitzsch, Ulrike [Research School of Earth Sciences, Australian National University, Canberra ACT 0200 (Australia); Christy, Andrew G., E-mail: Andrew.Christy@anu.edu.a [Research School of Earth Sciences, Australian National University, Canberra ACT 0200 (Australia); Willis, Anthony C. [Research School of Chemistry, Australian National University, Canberra ACT 0200 (Australia); Ellis, David J. [Research School of Earth Sciences, Australian National University, Canberra ACT 0200 (Australia)

    2010-03-15T23:59:59.000Z

    A new compound, CuZrTiO{sub 5}, was synthesized as strongly pleochroic green crystals from the oxides between 995 and 1010 deg. C, 1 atm. Its crystal structure was determined by single crystal XRD, resulting in R (F{sup 2}>2sigma(F{sup 2}))=0.032 and wR (all data)=0.079). CuZrTiO{sub 5} is orthorhombic, space group P2{sub 1}2{sub 1}2{sub 1}, a=3.5871(3) A, b=6.6968(4) A, c=14.6679(9) A, V=352.35(4) A{sup 3}, Z=4. The structure is topologically similar to In{sub 2}TiO{sub 5} but differs in space group and cation coordination. CuZrTiO{sub 5} has relatively regular TiO{sub 6} polyhedra, but coordination is 7+1 for Zr, and 4+2 for Cu due to the Jahn-Teller effect. Ordering of the long Cu-O bonds causes reduction in symmetry relative to In{sub 2}TiO{sub 5}. Layers of Cu alternate with Ti+Zr on (001), giving rise to a distinct cleavage. Bond valence sums on Ti and Zr are far from ideal, which appears due to the limited ability of this structural topology to avoid close next-nearest neighbour distances. - Graphical abstract: The new compound CuZrTiO{sub 5} is orthorhombic (P2{sub 1}2{sub 1}2{sub 1}), with a=3.5871(3) A, b=6.6968(4) A, c=14.6679(9) A. The structure, determined with single crystal XRD, represents a new crystal structure type that is a slight distortion of that of In{sub 2}TiO{sub 5} but differs in space group and cation coordination.

  3. Local structure around Er{sup 3+} in SiO{sub 2}-HfO{sub 2} glassy waveguides using EXAFS

    SciTech Connect (OSTI)

    Afify, N. D.; Dalba, G.; Armellini, C.; Ferrari, M.; Rocca, F.; Kuzmin, A. [Dipartimento di Fisica, Universita degli Studi di Trento, Via Sommarive 14, I-38100 Povo (Trento) (Italy); IFN-CNR, Istituto di Fotonica e Nanotecnologie del Consiglio Nazionale delle Ricerche, Sezione FBK-CeFSA di Trento, Via alla Cascata 56/C, I-38100 Povo (Trento) (Italy); Institute of Solid State Physics, University of Latvia, LV-1063 RIGA (Latvia)

    2007-07-01T23:59:59.000Z

    Er{sup 3+}-doped SiO{sub 2}-HfO{sub 2} glassy waveguides with HfO{sub 2} concentrations ranging from 10 to 50 mol % were prepared using the sol-gel route and deposited on v-SiO{sub 2} substrates using the dip-coating technique. The local environment around Er{sup 3+} ions was determined from Er L{sub 3}-edge extended x-ray-absorption fine-structure (EXAFS) measurements. The first coordination shell around Er{sup 3+} ions is composed of oxygen atoms. Hafnium is the main constituent of the second coordination shell of Er{sup 3+}, differing from the cases of pure SiO{sub 2} and SiO{sub 2}-TiO{sub 2} glassy hosts, in which silicon is the main atomic species. The local structure around Er{sup 3+} ions has been found to be independent on HfO{sub 2} concentration within the studied composition range. This fact implies that Er{sup 3+} ions are preferentially dispersed in HfO{sub 2}-rich regions of the glassy waveguide, even at the lowest HfO{sub 2} concentration. For all samples, no Er{sup 3+}-Er{sup 3+} coordination shell has been detected by EXAFS. The presented structural results allow us to understand some spectroscopic properties typical of Er{sup 3+}-doped SiO{sub 2} glassy waveguides co-doped with HfO{sub 2}.

  4. KCP R.A'S

    National Nuclear Security Administration (NNSA)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary) "ofEarlyEnergyDepartmentNational NuclearhasAdministration77NuclearSecurity Campus PreproposalJordan |

  5. Microsoft Word - Ra-15

    Broader source: Energy.gov (indexed) [DOE]

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary) "ofEarly Careerlumens_placard-green.eps MoreWSRC-STI-2007-00250 Rev. 05 Oak RidgeBob Charrow Date:

  6. Diffusion-governed-asymmetric growth of amorphous layer under solid-state reaction in Ni-Zr multilayers

    SciTech Connect (OSTI)

    Liu, B.X.; Lai, W.S. [Tsinghua Univ., Beijing (China). Dept. of Materials Science and Engineering

    1998-12-31T23:59:59.000Z

    A molecular-dynamics simulation with an n-body potential was performed to study solid-state amorphization in the Ni-Zr system upon annealing at medium temperatures ranging from 300 to 600 C. The models for simulation were a Zr-Ni-Zr sandwich consisting of both hcp Zr and fcc Ni (001) atomic planes and a bilayer with a thin preset disordered interfacial layer, respectively, for revealing the detailed amorphization process and the growing kinetics of an amorphous layer upon solid-state reaction. The simulation results demonstrated, for the first time, that the atomic process proceeded through first diffusion, then alloying and eventually amorphization. In other words, amorphization was controlled by a diffusion-limited reaction and the growth kinetics of the amorphous layer followed exactly a t{sup 1/2} law. Another interesting finding was that the growing speeds of the amorphous layer exhibited an asymmetric behavior, i.e, the amorphous layer extended faster towards Ni lattice than that directed to Zr side. Besides, it was also found that an initiation of amorphization upon annealing was dependent to the interfacial textures, i.e., amorphization could take place when the interfaces were composed of the more open atomic planes, whereas it was suppressed if the interfaces were constructed with the close-packed planes of both lattices.

  7. Effects of fluorine incorporation into HfO{sub 2} gate dielectrics on InP and In{sub 0.53}Ga{sub 0.47}As metal-oxide-semiconductor field-effect-transistors

    SciTech Connect (OSTI)

    Chen Yenting; Zhao Han; Wang Yanzhen; Xue Fei; Zhou Fei; Lee, Jack C. [Department of Electrical and Computer Engineering, Microelectronics Research Center, University of Texas at Austin, Texas 78758 (United States)

    2010-06-21T23:59:59.000Z

    In this work, the effects of fluorine (F) incorporation on electrical characteristics of HfO{sub 2}/InP and HfO{sub 2}/In{sub 0.53}Ga{sub 0.47}As gate stack are presented. F had been introduced into HfO{sub 2} gate dielectric by postgate CF{sub 4} plasma treatment, which was confirmed by x-ray photoelectron spectroscopy analysis and a secondary ion mass spectrometry technique. Compared to the control sample, fluorinated samples had great improvements in subthreshold swing, hysteresis, the normalized extrinsic transconductance, and the normalized drain current. These improvements can be attributed to the reduction in fixed charge in the HfO{sub 2} bulk and less interface trap density at the HfO{sub 2}/III-V interface.

  8. Electron microscopy of phase and structural transformations in soft magnetic nanocrystalline Fe-Zr-N films

    SciTech Connect (OSTI)

    Zhigalina, O. M., E-mail: zhigal@ns.crys.ras.ru; Khmelenin, D. N. [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation)] [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation); Sheftel', E. N.; Usmanova, G. Sh. [Russian Academy of Sciences, Baikov Institute of Metallurgy and Materials Science (Russian Federation)] [Russian Academy of Sciences, Baikov Institute of Metallurgy and Materials Science (Russian Federation); Vasil'ev, A. L. [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation)] [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation); Carlsson, A. [FEI Company (Netherlands)] [FEI Company (Netherlands)

    2013-03-15T23:59:59.000Z

    The effect of deposition conditions (film thickness) on the structure of soft magnetic Fe{sub 80-78}Zr{sub 10}N{sub 10-12} films formed by reactive magnetron deposition on a heat-resistant glass substrate has been investigated by analytical transmission electron microscopy, high-resolution electron microscopy, and diffraction analysis. The processes of evolution of the phase and structural state of films and the film-substrate interface upon annealing in the temperature range of 200-650 Degree-Sign C have been analyzed taking into account the thermodynamic, kinetic, and structural factors and the specific features of the nanocrystalline state.

  9. Beta-decay properties of Zr and Mo neutron-rich isotopes

    E-Print Network [OSTI]

    P. Sarriguren; J. Pereira

    2010-06-08T23:59:59.000Z

    Gamow-Teller strength distributions, beta-decay half-lives, and beta-delayed neutron emission are investigated in neutron-rich Zr and Mo isotopes within a deformed quasiparticle random-phase approximation. The approach is based on a self-consistent Skyrme Hartree-Fock mean field with pairing correlations and residual separable particle-hole and particle-particle forces. Comparison with recent measurements of half-lives stresses the important role that nuclear deformation plays in the description of beta-decay properties in this mass region.

  10. EUREM 12, Brno, Czech Republic, July 9-14, 2000 P 257 High yield incorporation of ZrCl4 into single wall carbon nanotubes

    E-Print Network [OSTI]

    Dunin-Borkowski, Rafal E.

    in a furnace, held at temperature for 1hr and then furnace cooled. The specimens were characterised using) show the filling product obtained from as-supplied ZrCl4. Figure 1(a) shows an empty SWNT tip. Below beam. The average filling yield for `as-supplied' ZrCl4 was estimated to be between 20-30%. #12;P 258

  11. Ab initio prediction of ordered ground-state structures in ZrO2-Y2O3 A. Predith,1

    E-Print Network [OSTI]

    Ceder, Gerbrand

    Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA 2Department from yttrium and every Zr has seven oxygen first nearest neighbors. The Zr-O bond lengths and oxygen, 82.45.Xy I. INTRODUCTION Zirconia doped with yttria is a common oxygen ion con- ductor used in oxygen

  12. Deposition of TiN and HfO{sub 2} in a commercial 200 mm remote plasma atomic layer deposition reactor

    SciTech Connect (OSTI)

    Heil, S. B. S.; Hemmen, J. L. van; Hodson, C. J.; Singh, N.; Klootwijk, J. H.; Roozeboom, F.; Sanden, M. C. M. van de; Kessels, W. M. M. [Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (Netherlands); Oxford Instruments Plasma Technology, North End, Yatton BS49 4AP (United Kingdom); Philips Research Laboratories, High Tech Campus 4, 5656 AE Eindhoven (Netherlands); NXP Semiconductors Research, High Tech Campus 4, 5656 AE Eindhoven (Netherlands); Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (Netherlands)

    2007-09-15T23:59:59.000Z

    The authors describe a remote plasma atomic layer deposition reactor (Oxford Instruments FlexAL trade mark sign ) that includes an inductively coupled plasma source and a load lock capable of handling substrates up to 200 mm in diameter. The deposition of titanium nitride (TiN) and hafnium oxide (HfO{sub 2}) is described for the combination of the metal-halide precursor TiCl{sub 4} and H{sub 2}-N{sub 2} plasma and the combination of the metallorganic precursor Hf[N(CH{sub 3})(C{sub 2}H{sub 5})]{sub 4} and O{sub 2} plasma, respectively. The influence of the plasma exposure time and substrate temperature has been studied and compositional, structural, and electrical properties are reported. TiN films with a low Cl impurity content were obtained at 350 deg. C at a growth rate of 0.35 A /cycle with an electrical resistivity as low as 150 {mu}{omega} cm. Carbon-free (detection limit <2 at. %) HfO{sub 2} films were obtained at a growth rate of 1.0 A /cycle at 290 deg. C. The thickness and resisitivity nonuniformity was <5% for the TiN and the thickness uniformality was <2% for the HfO{sub 2} films as determined over 200 mm wafers.

  13. Atomic layer deposition of Hf{sub x}Al{sub y}C{sub z} as a work function material in metal gate MOS devices

    SciTech Connect (OSTI)

    Lee, Albert, E-mail: alee@intermolecular.com; Fuchigami, Nobi; Pisharoty, Divya; Hong, Zhendong; Haywood, Ed; Joshi, Amol; Mujumdar, Salil; Bodke, Ashish; Karlsson, Olov [Intermolecular, 3011 North First Street, San Jose, California 95134 (United States); Kim, Hoon; Choi, Kisik [GLOBALFOUNDRIES Technology Research Group, 257 Fuller Road, Albany, New York 12309 (United States); Besser, Paul [GLOBALFOUNDRIES, 1050 East Arques, Sunnyvale, California 94085 (United States)

    2014-01-15T23:59:59.000Z

    As advanced silicon semiconductor devices are transitioning from planar to 3D structures, new materials and processes are needed to control the device characteristics. Atomic layer deposition (ALD) of Hf{sub x}Al{sub y}C{sub z} films using hafnium chloride and trimethylaluminum precursors was combined with postdeposition anneals and ALD liners to control the device characteristics in high-k metal-gate devices. Combinatorial process methods and technologies were employed for rapid electrical and materials characterization of various materials stacks. The effective work function in metal–oxide–semiconductor capacitor devices with the Hf{sub x}Al{sub y}C{sub z} layer coupled with an ALD HfO{sub 2} dielectric was quantified to be mid-gap at ?4.6?eV. Thus, Hf{sub x}Al{sub y}C{sub z} is a promising metal gate work function material that allows for the tuning of device threshold voltages (V{sub th}) for anticipated multi-V{sub th} integrated circuit devices.

  14. Ion-radical synergy in HfO{sub 2} etching studied with a XeF{sub 2}/Ar{sup +} beam setup

    SciTech Connect (OSTI)

    Gevers, P. M.; Beijerinck, H. C. W.; Sanden, M. C. M. van de; Kessels, W. M. M. [Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (Netherlands)

    2008-04-15T23:59:59.000Z

    To gain more insight into fundamental aspects of the etching behavior of Hf-based high-k materials in plasma etch reactors, HfO{sub 2} films were etched in a multiple-beam setup consisting of a low energy Ar{sup +} ion beam and a XeF{sub 2} radical beam. The etch rate and etch products were monitored by real-time ellipsometry and mass spectrometry, respectively. Although etching of HfO{sub 2} in XeF{sub 2}/Ar{sup +} chemistry is mainly a physical effect, an unambiguous proof of the ion-radical synergistic effect for the etching of HfO{sub 2} is presented. The etch yield for 400 eV Ar{sup +} ions at a substrate temperature of 300 deg. C was 0.3 atoms/ion for Ar{sup +} sputtering and increased to 2 atoms/ion when XeF{sub 2} was also supplied. The etch yield proved to follow the common square root of ion energy dependence both for pure sputtering and radical enhanced etching, with a threshold energy at room temperature of 69{+-}17 eV for Ar{sup +} ions and 54{+-}14 eV for Ar{sup +} ions with XeF{sub 2}.

  15. Band offsets of Al{sub 2}O{sub 3} and HfO{sub 2} oxides deposited by atomic layer deposition technique on hydrogenated diamond

    SciTech Connect (OSTI)

    Liu, J. W.; Liao, M. Y.; Imura, M. [Optical and Electronic Materials Unit, National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); Koide, Y. [Optical and Electronic Materials Unit, National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); Nanofabrication Platform, NIMS, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan); Center of Materials Research for Low Carbon Emission, NIMS, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan)

    2012-12-17T23:59:59.000Z

    High-k oxide insulators (Al{sub 2}O{sub 3} and HfO{sub 2}) have been deposited on a single crystalline hydrogenated diamond (H-diamond) epilayer by an atomic layer deposition technique at temperature as low as 120 Degree-Sign C. Interfacial electronic band structures are characterized by X-ray photoelectron spectroscopy. Based on core-level binding energies and valence band maximum values, valence band offsets are found to be 2.9 {+-} 0.2 and 2.6 {+-} 0.2 eV for Al{sub 2}O{sub 3}/H-diamond and HfO{sub 2}/H-diamond heterojunctions, respectively. Band gaps of the Al{sub 2}O{sub 3} and HfO{sub 2} have been determined to be 7.2 {+-} 0.2 and 5.4 {+-} 0.2 eV by measuring O 1s energy loss spectra, respectively. Both the Al{sub 2}O{sub 3}/H-diamond and HfO{sub 2}/H-diamond heterojunctions are concluded to be type-II staggered band configurations with conduction band offsets of 1.2 {+-} 0.2 and 2.7 {+-} 0.2 eV, respectively.

  16. Addendum to ''Phase selection and transition in Hf-rich hafnia-titania nanolaminates'' (on SiO{sub 2}) [J. Appl. Phys. 109, 123523 (2011)]: Hafnon formation

    SciTech Connect (OSTI)

    Cisneros-Morales, Massiel Cristina; Aita, Carolyn Rubin [Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, P.O. Box 413, Milwaukee, Wisconsin 53201 (United States)

    2012-05-15T23:59:59.000Z

    Continued investigation of hafnia-titania nanolaminates on silica substrates after long term annealing shows that hafnon (HfSiO{sub 4}) is formed, in addition to the previously reported phases. Here, a 293 nm-thick stack of 5 nm HfO{sub 2}-4 nm TiO{sub 2} bilayers (0.51 mole fraction HfO{sub 2}) is sputter deposited on fused SiO{sub 2} and annealed in air at 1173 K for up to 192 h and then at 1273 K for up to 96 h. X-ray diffraction shows that hafnon crystallizes after 24 h at 1273 K. Micro-Raman spectroscopy/microscopy shows that hafnon crystallization is heterogeneous. No film-substrate reaction is observed for single layer HfO{sub 2} on SiO{sub 2} annealed under similar conditions. We suggest the nanolaminate's complex annealed microstructure provides fast diffusion paths that enable hafnon formation.

  17. Quantum dynamics of molecular multiphoton excitation in intense laser and static electric fields: Floquet theory, quasienergy spectra, and application to the HF molecule

    E-Print Network [OSTI]

    Chu, Shih-I; Tietz, James V.; Datta, Krishna K.

    1982-01-01T23:59:59.000Z

    of the HF molecule as functions of field strengths and frequency. Nonlinear effects such as power broadening, dynamic Stark shift, Autler–Townes multiplet splitting, hole burning, and S?hump behaviors, etc., are observed and discussed in terms of quasienergy...

  18. ULF wave occurrence statistics in a high-latitude HF Doppler sounder D. M. Wright, T. K. Yeoman, T. B. Jones

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    ULF wave occurrence statistics in a high-latitude HF Doppler sounder D. M. Wright, T. K. Yeoman, T was to establish the optimum con®guration for a new high-latitude Doppler sounder experiment, called DOPE (Wright, 1996; Wright et al., 1997), and to determine the likelihood of the experiment observing pulsation eects

  19. In situ study of HfO{sub 2} atomic layer deposition on InP(100)

    SciTech Connect (OSTI)

    Dong, H.; Brennan, B.; Kim, J.; Hinkle, C. L.; Wallace, R. M. [Department of Materials Science and Engineering, University of Texas at Dallas, Richardson, Texas 75080 (United States)] [Department of Materials Science and Engineering, University of Texas at Dallas, Richardson, Texas 75080 (United States); Zhernokletov, D. [Department of Physics, University of Texas at Dallas, Richardson, Texas 75080 (United States)] [Department of Physics, University of Texas at Dallas, Richardson, Texas 75080 (United States)

    2013-04-29T23:59:59.000Z

    The interfacial chemistry of the native oxide and chemically treated InP samples during atomic layer deposition (ALD) HfO{sub 2} growth at 250 Degree-Sign C has been studied by in situ X-ray photoelectron spectroscopy. The In-oxide concentration is seen to gradually decrease on the native oxide and acid etched samples. No significant changes of the P-oxide concentrations are detected, while the P-oxides chemical states are seen to change gradually during the initial cycles of ALD on the native oxide and the chemically treated samples. (NH{sub 4}){sub 2}S treatment strongly decreases In-oxide and P-oxide concentrations prior to ALD and maintains low concentrations during the ALD process.

  20. Interfacial Layer Growth Condition Dependent Carrier Transport Mechanisms in HfO2/SiO2 Gate Stacks

    SciTech Connect (OSTI)

    Sahoo, S. K.; Misra, D.

    2012-06-04T23:59:59.000Z

    The temperature and field dependent leakage current in HfO{sub 2}/SiO{sub 2} gate stack for in situ steam grown and chemical interfacial layers (ILs) are studied in the temperature range of 20 C to 105 C. Poole-Frenkel mechanism in high field whereas Ohmic conduction in low field region are dominant for both devices. Leakage current decreases whereas both trap energy level ({phi}{sub t}) and activation energy (E{sub a}) increase for chemically grown IL devices. The trap level energy, ({phi}{sub t}) -0.2 eV, indicates that doubly charged oxygen vacancies (V{sup 2-}) are the active electron traps which contribute to the leakage current in these gate stacks.

  1. Fundamental science investigations to develop a 6-MV laser triggered gas switch for ZR: first annual report.

    SciTech Connect (OSTI)

    Warne, Larry Kevin; Van Den Avyle, James A.; Lehr, Jane Marie; Rose, David (Voss Scientific, Albuquerque, NM); Krompholz, Hermann G. (Texas Tech University, Lubbock, TX); Vela, Russell (Texas Tech University, Lubbock, TX); Jorgenson, Roy Eberhardt; Timoshkin, Igor (University of Strathclyde, Glasgow, Scotland); Woodworth, Joseph Ray; Prestwich, Kenneth Randel (Voss Scientific, Albuquerque, NM); Krile, John (Texas Tech University, Lubbock, TX); Given, Martin (University of Strathclyde, Glasgow, Scotland); McKee, G. Randall; Rosenthal, Stephen Edgar; Struve, Kenneth William; Welch, Dale Robert (Voss Scientific, Albuquerque, NM); Benwell, Andrew L. (University of Missouri-Columbia, Columbia, Missouri); Kovaleski, Scott (University of Missouri-Columbia, Columbia, Missouri); LeChien, Keith, R.; Johnson, David (Titan Pulse Sciences Division); Fouracre, R.A. (University of Strathclyde, Glasgow, Scotland); Yeckel, Chris (University of Missouri-Columbia, Columbia, Missouri); Wakeland, Peter Eric (Ktech Corporation, Albuquerque, NM); Miller, A. R. (Titan Pulse Sciences Division); Hodge, Keith Conquest (Ktech Corporation, Albuquerque, NM); Pasik, Michael Francis; Savage, Mark Edward; Maenchen, John Eric; Curry, Randy D. (University of Missouri-Columbia, Columbia, Missouri); Feltz, Greg (Ktech Corporation, Albuquerque, NM); Bliss, David Emery; MacGregor, Scott (University of Strathclyde, Glasgow, Scotland); Corley, J. P. (Ktech Corporation, Albuquerque, NM); Anaya, Victor (Ktech Corporation, Albuquerque, NM); Wallace, Zachariah (Ktech Corporation, Albuquerque, NM); Thoma, Carsten (Voss Scientific, Albuquerque, NM); Neuber, Andreas. (Texas Tech University, Lubbock, TX)

    2007-03-01T23:59:59.000Z

    In October 2005, an intensive three-year Laser Triggered Gas Switch (LTGS) development program was initiated to investigate and solve observed performance and reliability issues with the LTGS for ZR. The approach taken has been one of mission-focused research: to revisit and reassess the design, to establish a fundamental understanding of LTGS operation and failure modes, and to test evolving operational hypotheses. This effort is aimed toward deploying an initial switch for ZR in 2007, on supporting rolling upgrades to ZR as the technology can be developed, and to prepare with scientific understanding for the even higher voltage switches anticipated needed for future high-yield accelerators. The ZR LTGS was identified as a potential area of concern quite early, but since initial assessments performed on a simplified Switch Test Bed (STB) at 5 MV showed 300-shot lifetimes on multiple switch builds, this component was judged acceptable. When the Z{sub 20} engineering module was brought online in October 2003 frequent flashovers of the plastic switch envelope were observed at the increased stresses required to compensate for the programmatically increased ZR load inductance. As of October 2006, there have been 1423 Z{sub 20} shots assessing a variety of LTGS designs. Numerous incremental and fundamental switch design modifications have been investigated. As we continue to investigate the LTGS, the basic science of plastic surface tracking, laser triggering, cascade breakdown, and optics degradation remain high-priority mission-focused research topics. Significant progress has been made and, while the switch does not yet achieve design requirements, we are on the path to develop successively better switches for rolling upgrade improvements to ZR. This report summarizes the work performed in FY 2006 by the large team. A high-level summary is followed by detailed individual topical reports.

  2. Intrinsic nanostructure in Zr2 xFe4Si16 y (x = 0.81, y = 6.06)

    SciTech Connect (OSTI)

    Smith, G J [Stony Brook University, Department of Physics and Astronomy; Simonson, Jack [Stony Brook University (SUNY); Prozorov, R. [Ames Laboratory and Iowa State University; Zhu, Y [Brookhaven National Laboratory (BNL); Aronson, M. [Stony Brook University, Department of Physics and Astronomy

    2014-01-01T23:59:59.000Z

    We present a study of the crystal structure and physical properties of single crystals of a new Fe-based ternary compound, Zr2 xFe4Si16 y (x = 0.81, y = 6.06). Zr1.19Fe4Si9.94 is a layered compound, where stoichiometric -FeSi2-derived slabs are separated by Zr-Si planes with substantial numbers of vacancies. High resolution transmission electron microscopy (HRTEM) experiments show that these Zr-Si layers consist of 3.5 nm domains where the Zr and Si vacancies are ordered within a supercell sixteen times the volume of the stoichiometric cell. Within these domains, the occupancies of the Zr and Si sites obey symmetry rules that permit only certain compositions, none of which by themselves reproduce the average composition found in x-ray diffraction experiments. Magnetic susceptibility and magnetization measurements reveal a small but appreciable number of magnetic moments that remain freely fluctuating to 1.8 K, while neutron diffraction confirms the absence of bulk magnetic order with a moment of 0.2 B or larger down to 1.5 K. Electrical resistivity measurements find that Zr1.19Fe4Si9.94 is metallic, and the modest value of the Sommerfeld coefficient of the specific heat = C/T suggests that quasi-particle masses are not particularly strongly enhanced. The onset of superconductivity at Tc 6 K results in a partial resistive transition and a small Meissner signal, although a bulk-like transition is found in the specific heat. Sharp peaks in the ac susceptibility signal the interplay of the normal skin depth and the London penetration depth, typical of a system in which nano-sized superconducting grains are separated by a non-superconducting host. Ultra low field differential magnetic susceptibility measurements reveal the presence of a surprisingly large number of trace magnetic and superconducting phases, suggesting that the Zr-Fe-Si ternary system could be a potentially rich source of new bulk superconductors.

  3. Preliminary study of niobium alloy contamination by transport through helium. [Nb-1Zr; Sm-Co; Hiperco 50 steel; alumina

    SciTech Connect (OSTI)

    Scheuermann, C.M.; Moore, T.J.; Wheeler, D.R.

    1987-01-12T23:59:59.000Z

    Preliminary tests were conducted to determine if interstitial element transport through a circulating helium working fluid was a potential problem in Brayton and Stirling space power systems. Test specimens exposed to a thermal gradient for up to 3000 h included Nb-1%Zr, a Sm-Co alloy, Hiperco 50 steel, and alumina to simulate various engine components of the Brayton and Stirling systems. Results indicate that helium transport of interstitial contaminants can be minimized over a 7-y life with monometallic Nb-1%Zr design. Exposure with other materials indicated a potential for interstitial contaminant transport.

  4. Repetitive Ultra-low Stress Induced Nanocrystallization in Amorphous Cu?Zr?Al Alloy Evidenced by in situ Nanoindentation

    E-Print Network [OSTI]

    Liu, Y.; Jian, J.; Lee, J. H.; Wang, C.; Cao, Q. P.; Gutierrez, C.; Wang, H.; Jiang, J. Z.; Zhang, X.

    2014-05-12T23:59:59.000Z

    ?Zr?Al Alloy Evidenced by in situ Nanoindentation Y. Liu a , J. Jian b , J.H. Lee b , C. Wang cd , Q.P. Cao cd , C. Gutierrez e , H. Wang ab , J.Z. Jiang cd & X. Zhang ae a Department of Materials Science and Engineering, Texas A&M University, College Station.... To cite this article: Y. Liu, J. Jian, J.H. Lee, C. Wang, Q.P. Cao, C. Gutierrez, H. Wang, J.Z. Jiang & X. Zhang (2014) Repetitive Ultra-low Stress Induced Nanocrystallization in Amorphous Cu?Zr?Al Alloy Evidenced by in situ Nanoindentation, Materials...

  5. Synthesis of ZrO{sub 2} nanoparticles by hydrothermal treatment

    SciTech Connect (OSTI)

    Machmudah, Siti, E-mail: machmudah@chem-eng.its.ac.id; Widiyastuti, W., E-mail: machmudah@chem-eng.its.ac.id; Prastuti, Okky Putri, E-mail: machmudah@chem-eng.its.ac.id; Nurtono, Tantular, E-mail: machmudah@chem-eng.its.ac.id; Winardi, Sugeng, E-mail: machmudah@chem-eng.its.ac.id [Chemical Engineering Department, Sepuluh Nopember Institute of Technology, Surabaya 60111 (Indonesia); Wahyudiono,; Kanda, Hideki; Goto, Motonobu [Department of Chemical Engineering, Nagoya University, Nagoya 464-8603 (Japan)

    2014-02-24T23:59:59.000Z

    Zirconium oxide (zirconia, ZrO{sub 2}) is the most common material used for electrolyte of solid oxide fuel cells (SOFCs). Zirconia has attracted attention for applications in optical coatings, buffer layers for growing superconductors, thermal-shield, corrosion resistant coatings, ionic conductors, and oxygen sensors, and for potential applications including transparent optical devices and electrochemical capacitor electrodes, fuel cells, catalysts, and advanced ceramics. In this work, zirconia particles were synthesized from ZrCl{sub 4} precursor with hydrothermal treatment in a batch reactor. Hydrothermal treatment may allow obtaining nanoparticles and sintered materials with controlled chemical and structural characteristics. Hydrothermal treatment was carried out at temperatures of 150 – 200°C with precursor concentration of 0.1 – 0.5 M. Zirconia particles obtained from this treatment were analyzed by using SEM, PSD and XRD to characterize the morphology, particle size distribution, and crystallinity, respectively. Based on the analysis, the size of zirconia particles were around 200 nm and it became smaller with decreasing precursor concentration. The increasing temperature caused the particles formed having uniform size. Zirconia particles formed by hydrothermal treatment were monoclinic, tetragonal and cubic crystal.

  6. Dissociation of trimethylgallium on the ZrB{sub 2}(0001) surface

    SciTech Connect (OSTI)

    Manandhar, Kedar; Trenary, Michael [Department of Chemistry, University of Illinois at Chicago, 845W Taylor St., Chicago, Illinois 60607 (United States)] [Department of Chemistry, University of Illinois at Chicago, 845W Taylor St., Chicago, Illinois 60607 (United States); Otani, Shigeki [National Institute for Material Science, 1-1 Namiki, Tsukuba-shi, Ibaraki 305-0044 (Japan)] [National Institute for Material Science, 1-1 Namiki, Tsukuba-shi, Ibaraki 305-0044 (Japan); Zapol, Peter [Materials Science Division, Argonne National Laboratory, 9700 S. Cass Ave., Argonne, Illinois 60439 (United States)] [Materials Science Division, Argonne National Laboratory, 9700 S. Cass Ave., Argonne, Illinois 60439 (United States)

    2013-11-15T23:59:59.000Z

    X-ray photoelectron spectroscopy and reflection absorption infrared spectroscopy (RAIRS) have been used to study the dissociative adsorption of trimethylgallium (TMG) on the ZrB{sub 2}(0001) surface. Spectra were obtained as a function of annealing temperature following TMG exposure at temperatures of 95 and 300 K, and also as a function of TMG exposure for a surface temperature of 300 K. After annealing above 220 K, a significant decrease in the relative concentration of carbon and gallium occurred accompanied by a shift of ?0.2 eV in the Ga 2p{sub 3/2} binding energy. The RAIR spectra show that after annealing to ?220 K, only one CH{sub 3} deformation band at 1196 cm{sup ?1} remains, the intensity of which is considerably decreased indicating loss of at least one methyl group from TMG. Further annealing leads to the sequential loss of the other methyl groups. The first methyl desorbs while the last two dissociate to deposit two C atoms per TMG molecule onto the ZrB{sub 2} surface.

  7. New Insights into Reaction Mechanisms of Ethanol Steam Reforming on Co-ZrO2

    SciTech Connect (OSTI)

    Sun, Junming; Karim, Ayman M.; Mei, Donghai; Engelhard, Mark H.; Bao, Xinhe; Wang, Yong

    2015-01-01T23:59:59.000Z

    The reaction pathway of ethanol steam reforming on Co-ZrO2 has been identified and the active sites associated with each step are proposed. Ethanol is converted to acetaldehyde and then to acetone, followed by acetone steam reforming. More than 90% carbon was found to follow this reaction pathway. N2-Sorption, X-ray Diffraction (XRD), Temperature Programmed Reduction (TPR), in situ X-ray Photoelectron Spectroscopy (XPS), Transmission Electron Microscopy, as well as theoretical Density Functional Theory (DFT) calculations have been employed to identify the structure and functionality of the catalysts, which was further used to correlate their performance in ESR. It was found that metallic cobalt is mainly responsible for the acetone steam reforming reactions; while, CoO and basic sites on the support play a key role in converting ethanol to acetone via dehydrogenation and condensation/ketonization reaction pathways. The current work provides fundamental understanding of the ethanol steam reforming reaction mechanisms on Co-ZrO2 catalysts and sheds light on the rational design of selective and durable ethanol steam reforming catalysts.

  8. Synthesis and characterization of rare earth doped ZrO{sub 2} nanophosphors

    SciTech Connect (OSTI)

    Agrawal, Sadhana, E-mail: sagrawal.phy@nitrr.ac.in, E-mail: jsvikasdubey@gmail.com; Dubey, Vikas, E-mail: sagrawal.phy@nitrr.ac.in, E-mail: jsvikasdubey@gmail.com [Department of Physics, National Institute of Technology, Raipur (C.G.) (India)

    2014-10-24T23:59:59.000Z

    In this paper, we reports synthesis, characterization and thermoluminescence (TL) glow curves of europium and dysprosium activated zirconium dioxide (ZrO{sub 2}: Eu{sup 3+}, Dy{sup 3+}) phosphor with variable concentration of europium and fixed concentration of dysprosium. The sample was prepared by the Solid state method; thereafter, the TL glow curves were recorded for different concentration of europium with 20 min UV exposure at a heating rate of 6.7°C/s. The trapping parameters for synthesized phosphors of ZrO{sub 2}: Eu{sup 3+}, Dy{sup 3+} have been calculated by using a peak shape method. The sample was characterized for structural analysis by XRD (X-ray diffraction) and morphological analysis by FEGSEM (field emission gun scanning electron microscope) and FTIR (Fourier transform infrared spectroscopy). The effect of variable europium concentration and fixed dysprosium concentration on TL studies were interpreted and the formation of trap depth and reproducibility of prepared phosphor were analyzed by TL glow curves. The peak temperature on TL less than 200°C shows the formation of deep trapping in prepared sample. The high temperature peak shows the less fading and more stability in prepared sample.

  9. Precipitation in a Cu–Cr–Zr–Mg alloy during aging

    SciTech Connect (OSTI)

    Cheng, J.Y., E-mail: bigchengjianyi@163.com; Shen, B.; Yu, F.X.

    2013-07-15T23:59:59.000Z

    The precipitation processes in a Cu-0.69Cr-0.10Zr-0.02Mg alloy aged at 450 °C and 550 °C have been investigated by transmission electron microscopy and high resolution transmission electron microscopy. The precipitation sequence in this alloy aged at 450 °C is: supersaturated solid solution ? Guinier–Preston zone (fcc Cr-rich phase) ? ordered fcc Cr-rich phase ? ordered bcc Cr-rich phase. The precipitation sequence in this alloy aged at 550 °C is: supersaturated solid solution ? ordered fcc Cr-rich phase ? ordered bcc Cr-rich phase. In the evolution of decomposition, the orientation relationship between the precipitates and the Cu matrix changes from cube-on-cube to Nishiyama–Wassermann orientation. The ordering of Cr-rich precipitates facilitates the formation of the bcc precipitates and promotes the development of Nishiyama–Wassermann orientation. - Highlights: • Two different precipitation sequences in the Cu–Cr–Zr–Mg alloy are proposed. • The changes in orientation relationship of the precipitates are presented. • The roles of ordering and coherent interface of the precipitates are discussed.

  10. Fuel element design for the enhanced destruction of plutonium in a nuclear reactor

    DOE Patents [OSTI]

    Crawford, Douglas C. (Idaho Falls, ID); Porter, Douglas L. (Idaho Falls, ID); Hayes, Steven L. (Idaho Falls, ID); Hill, Robert N. (Bolingbrook, IL)

    1999-01-01T23:59:59.000Z

    A uranium-free fuel for a fast nuclear reactor comprising an alloy of Pu, Zr and Hf, wherein Hf is present in an amount less than about 10% by weight of the alloy. The fuel may be in the form of a Pu alloy surrounded by a Zr--Hf alloy or an alloy of Pu--Zr--Hf or a combination of both.

  11. Fuel element design for the enhanced destruction of plutonium in a nuclear reactor

    SciTech Connect (OSTI)

    Crawford, Douglas C.; Porter, Douglas L.; Hayes, Steven L.; Hill, Robert N.

    1997-12-01T23:59:59.000Z

    A uranium-free fuel for a fast nuclear reactor comprising an alloy of Pu, Zr and Hf, wherein Hf is present in an amount less than about 10% by weight of the alloy. The fuel may be in the form of a Pu alloy surrounded by a Zr-Hf alloy or an alloy of Pu-Zr-Hf or a combination of both.

  12. Fuel element design for the enhanced destruction of plutonium in a nuclear reactor

    DOE Patents [OSTI]

    Crawford, D.C.; Porter, D.L.; Hayes, S.L.; Hill, R.N.

    1999-03-23T23:59:59.000Z

    A uranium-free fuel for a fast nuclear reactor comprising an alloy of Pu, Zr and Hf, wherein Hf is present in an amount less than about 10% by weight of the alloy. The fuel may be in the form of a Pu alloy surrounded by a Zr--Hf alloy or an alloy of Pu--Zr--Hf or a combination of both. 7 figs.

  13. Precipitation and Thermal Fatigue in Ni-Ti-Zr Shape Memory Alloy Thin Films by Combinatorial nanoCalorimetry

    E-Print Network [OSTI]

    - elastic martensitic phase transformation. They demonstrate enhanced power density compared to other associated with the transformation hysteresis by alloying tertiary components [6,7]. Ni-Ti-Zr is seen as one transformation. The response of the samples to heat treatments depends on composition and is controlled

  14. Effect of La2Zr2O7 on Interfacial Resistance in Solid Oxide J. R. Smith,a

    E-Print Network [OSTI]

    Florida, University of

    Effect of La2Zr2O7 on Interfacial Resistance in Solid Oxide Fuel Cells A. Chen,a J. R. Smith,a K. L manuscript received August 9, 2010. Published September 14, 2010. Solid oxide fuel cells SOFC are energy to gas phase transport in porous media, is controlled by optimizing electrode mi- crostructures

  15. Kinetic Modeling of Slurry Propylene Polymerization using rac-Et(Ind)2ZrCl2/MAO

    E-Print Network [OSTI]

    by the isospecific metallocene rac-Et(Ind)2ZrCl2/MAO was investigated using a semi-batch reactor. A full factorial using a systematic optimization strategy. The model predicts that the insertion of the first propylene such understanding and affords opportunities for optimization. Thermoplastic industries for polypropylene (PP

  16. First-principles study of the stability and migration of Kr, I and Xe in ZrO2

    SciTech Connect (OSTI)

    Xiao, Haiyan [University of Tennessee, Knoxville (UTK); Weber, William J [ORNL; Zhang, Yanwen [ORNL

    2014-01-01T23:59:59.000Z

    The stability and migration of Kr, I and Xe in bulk ZrO2 and on the ZrO2 (1 1 1) surface have been studied by standard density functional theory (DFT) and the DFT-D2 method that corrects for the van der Waals interaction. Both methods show that Kr and Xe prefer to incorporate in the bulk phase rather than adsorb on the surface, and Xe is very mobile in the bulk state. For Kr and Xe adsorption on the surface, van der Waals interaction dominates, causing the weak interaction between the adsorbate and substrate. Iodine is found to have comparable stability in both phases and forms I O bonds with strong covalency. It exhibits higher mobility on the surface than in the bulk ZrO2, and diffusion from bulk-like state to surface state is an exothermic process. The fission product behavior in ZrO2 is shown to be a complicated synergetic effect of fission product atomic size, electron negativity, occupation site and phase structure of the host.

  17. Intrinsic Nanostructure in Zr2-xFe4Si16-y (x=0.81, y=6.06)

    SciTech Connect (OSTI)

    Smith, G J [Stony Brook University; Simonson, J W [Stony Brook University; Orvis, T [Stony Brook University; Marques, C [Stony Brook University; Grose, J E [Stony Brook University; Kistner-Morris, J J [Stony Brook University; Wu, L [Brookhaven National Laboratory; Cho, Kyuil [Ames Laboratory; Kim, Hyong june [Ames Laboratory; Tanatar, Makariy A [Ames Laboratory; Garlea, V O [Oak Ridge National Laboratory; Prozorov, Ruslan [Ames Laboratory; Zhu, Y [Brookhaven National Laboratory; Aronson, M C [Stony Brook University

    2014-09-17T23:59:59.000Z

    We present a study of the crystal structure and physical properties of single crystals of a new Fe-based ternary compound, Zr2?x Fe4Si16?y(x=0.81,y=6.06). Zr1.19 Fe4Si9.94 is a layered compound, where stoichiometric ?-FeSi2-derived slabs are separated by Zr-Si planes with substantial numbers of vacancies. High resolution transmission electron microscopy (HRTEM) experiments show that these Zr-Si layers consist of 3.5nm domains where the Zrand Si vacancies are ordered within a supercell sixteen times the volume of the stoichiometric cell. Within these domains, the occupancies of the Zr and Si sites obey symmetry rules that permit only certain compositions, none of which by themselves reproduce the average composition found in x-ray diffraction experiments. Magnetic susceptibility and magnetization measurements reveal a small but appreciable number of magnetic moments that remain freely fluctuating to 1.8K, while neutron diffraction confirms the absence of bulk magnetic order with a moment of 0.2? B or larger down to 1.5K. Electrical resistivity measurements find that Zr1.19Fe4Si9.94 is metallic, and the modest value of the Sommerfeld coefficient of the specific heat ? = C/T suggests that quasi-particle masses are not particularly strongly enhanced. The onset of superconductivity at Tc 6K results in a partial resistive transition and a small Meissner signal, although a bulk-like transition is found in the specific heat. Sharp peaks in the ac susceptibility signal the interplay of the normal skin depth and the London penetration depth, typical of a system in which nano-sized superconducting grains are separated by a on-superconducting host. Ultra low field differential magnetic susceptibility measurements reveal the presence of a surprisingly large number of trace magnetic and superconducting phases, suggesting that the Zr-Fe-Si ternary system could be a potentially rich source of new bulk superconductor.

  18. Pre- and post-irradiation characterization and properties measurements of ZrC coated surrogate TRISO particles

    SciTech Connect (OSTI)

    Vasudevamurthy, Gokul [ORNL; Katoh, Yutai [ORNL; Hunn, John D [ORNL; Snead, Lance Lewis [ORNL

    2010-09-01T23:59:59.000Z

    Zirconium carbide is a candidate to either replace or supplement silicon carbide as a coating material in TRISO fuel particles for high temperature gas-cooled reactor fuels. Six sets of ZrC coated surrogate microsphere samples, fabricated by the Japan Atomic Energy Agency using the fluidized bed chemical vapor deposition method, were irradiated in the High Flux Isotope Reactor at the Oak Ridge National Laboratory. These developmental samples available for the irradiation experiment were in conditions of either as-fabricated coated particles or particles that had been heat-treated to simulate the fuel compacting process. Five sets of samples were composed of nominally stoichiometric compositions, with the sixth being richer in carbon (C/Zr = 1.4). The samples were irradiated at 800 and 1250 C with fast neutron fluences of 2 and 6 dpa. Post-irradiation, the samples were retrieved from the irradiation capsules followed by microstructural examination performed at the Oak Ridge National Laboratory's Low Activation Materials Development and Analysis Laboratory. This work was supported by the US Department of Energy Office of Nuclear Energy's Advanced Gas Reactor program as part of International Nuclear Energy Research Initiative collaboration with Japan. This report includes progress from that INERI collaboration, as well as results of some follow-up examination of the irradiated specimens. Post-irradiation examination items included microstructural characterization, and nanoindentation hardness/modulus measurements. The examinations revealed grain size enhancement and softening as the primary effects of both heat-treatment and irradiation in stoichiometric ZrC with a non-layered, homogeneous grain structure, raising serious concerns on the mechanical suitability of these particular developmental coatings as a replacement for SiC in TRISO fuel. Samples with either free carbon or carbon-rich layers dispersed in the ZrC coatings experienced negligible grain size enhancement during both heat treatment and irradiation. However, these samples experienced irradiation induced softening similar to stoichiometric ZrC samples.

  19. On the densification of cubic ZrO{sub 2} nanocondensates by capillarity force and turbostratic C–Si–H multiple shell

    SciTech Connect (OSTI)

    Wu, Chao-Hsien [Department of Materials and Optoelectronic Science, National Sun Yat-sen University, Kaohsiung 80424, Taiwan, ROC (China); Chen, Shuei-Yuan [Department of Mechanical and Automation Engineering, I-Shou University, Kaohsiung 84001, Taiwan, ROC (China); Shen, Pouyan, E-mail: pshen@mail.nsysu.edu.tw [Department of Materials and Optoelectronic Science, National Sun Yat-sen University, Kaohsiung 80424, Taiwan, ROC (China)

    2013-04-15T23:59:59.000Z

    A turbostratic C–Si–H lamellar phase with 0.35–0.39 nm interspacing and ZrO{sub 2} condensates having cubic (c), tetragonal and monoclinic structures stabilized by increasing particle size were synthesized by pulsed laser ablation on Zr plate in TEOS and characterized by X-ray/electron diffraction and optical spectroscopy. The c-ZrO{sub 2} phase ca. 10% denser than the ambient lattice was stabilized as 3–10 nm sized cubo-octahedral nanoparticles but as abnormal large-sized (up to 30 nm) ones when encapsulated by the C{sub 1?x}Si{sub x}:H multiple shell with defective graphite-like structure units to exert an effective compressive stress. The potential application of such core–shell nanostructure with enhanced binding of Zr and O ions and implication for natural dynamic occurrence of the C{sub 1?x}Si{sub x}:H phase are addressed. - Graphical abstract: Lattice image of a typical cubic-ZrO{sub 2} particle densified by the turbostratic Si{sub x}C{sub 1?x}:H shell. Highlights: ? Turbostratic C–Si–H lamellar phase and ZrO{sub 2} condensates were synthesized by PLA. ? The c-ZrO{sub 2} phase ca. 10% denser than the ambient lattice was stabilized as 3–10 nm. ? The c-ZrO{sub 2} particles up to 30 nm were densified when encapsulated by the C{sub 1?x}Si{sub x}:H multiple shell. ? Tight ion binding of the c-ZrO{sub 2} due to capillarity force and turbostratic shell.

  20. Isoscalar giant dipole resonance in Zr-90, Sn-116, and Pb-208

    E-Print Network [OSTI]

    Clark, HL; Lui, YW; Youngblood, David H.

    2001-01-01T23:59:59.000Z

    0.26a 0.545b 43.3 61.4 7.75 0.567 aReference @13#. bReference @19#. Isoscalar giant dipole resonanc H. L. Clark, Y.-W. Lui Cyclotron Institute, Texas A&M University ~Received 30 August 2000; Strength functions for isoscalar dipole excitations... density for the ISGDR is @6# r~r !52b1 /RA3@3r2d/dr110r25/3^r2&d/dr1e~rd2/dr2 14d/dr !#ro~r !. For one state which exhausts the energy weighted sum rule @6# ?2001 The American Physical Society1 inelasti e RAPID COMMUNICATIONS H. L. CLARK, Y.-W. LUI...

  1. Investigation of oxygen point defects in cubic ZrO2 by density functional theory

    SciTech Connect (OSTI)

    Liu, Bin [ORNL] [ORNL; Xiao, Haiyan [University of Tennessee, Knoxville (UTK)] [University of Tennessee, Knoxville (UTK); Zhang, Yanwen [ORNL] [ORNL; Aidhy, Dilpuneet S [ORNL] [ORNL; Weber, William J [ORNL] [ORNL

    2014-01-01T23:59:59.000Z

    The energetics of formation and migration of the oxygen vacancy and interstitial in cubic ZrO2 are investigated by density functional theory calculations. In an O-rich environment, the negatively charged oxygen interstitial is the most dominant defect whereas, the positively charged oxygen vacancy is the most dominant defect under O-poor conditions. Oxygen interstitial migration occurs by the interstitialcy and the direct interstitial mechanisms, with calculated migration energy barriers of 2.94 eV and 2.15 eV, respectively. For the oxygen vacancy, diffusion is preferred along the <100> direction, and the calculated energy barriers are 0.26 eV for , 0.27 eV for and 0.54 eV for . These results indicate that oxygen diffusivity is higher through the vacancy-migration mechanism.

  2. Rapid Relaxation and Embrittlement of Zr-based Bulk Metallic Glasses by Electropulsing

    SciTech Connect (OSTI)

    Yiu, P [Department of Materials Science and Engineering, National Taiwan University, Taipei 106, Taiwan; Chen, Y. C. [National Taiwan University of Science & Technology; Chu, J. P. [National Taiwan Ocean University; Chang, S Y [National Chung Hsing University; Bei, Hongbin [ORNL; Jang, J. S.C. [National Central University, Jhongli 32001, Taiwan; Hsueh, C. H. [Department of Materials Science and Engineering, National Taiwan University, Taipei 106, Taiwan

    2013-01-01T23:59:59.000Z

    Mechanical relaxation and embrittlement of Zr52.5Cu17.9Ni14.6Al10Ti5 bulk metallic glasses were achieved rapidly by the direct current electropulsing treatment. The temperature profile was recorded by an infrared camera and it was found to be non-uniform in the treated specimen. Specifically, temperatures below the glass transition temperature, near and above the crystallization temperature could be ach- ieved, respectively, at different locations in the same treated specimen. Two sets of nanoindentation were conducted. While the first set investigated the mechanical properties of three individually elec- tropulsed specimens with different conditions, the second set indented a single treated specimen along its temperature gradient. Both sets of indentation revealed that by Joule heating to different tempera- tures, relaxation, embrittlement, and crystallization were significantly accelerated by electrical pulses. Results suggest that electropulsing provides an opportunity to simultaneously achieve plastic forming and mechanical property control of metallic glasses.

  3. Gamow-Teller response in deformed even and odd neutron-rich Zr and Mo isotopes

    E-Print Network [OSTI]

    P. Sarriguren; A. Algora; J. Pereira

    2014-03-05T23:59:59.000Z

    Beta-decay properties of neutron-rich Zr and Mo isotopes are investigated within a microscopic theoretical approach based on the proton-neutron quasiparticle random-phase approximation. The underlying mean field is described self-consistently from deformed Skyrme Hartree-Fock calculations with pairing correlations. Residual separable particle-hole and particle-particle forces are also included in the formalism. The structural evolution in these isotopic chains including both even and odd isotopes is analyzed in terms of the equilibrium deformed shapes. Gamow-Teller strength distributions, beta-decay half-lives, and beta-delayed neutron-emission probabilities are studied, stressing their relevance to describe the path of the nucleosynthesis rapid neutron capture process.

  4. High performance organic field-effect transistors with ultra-thin HfO{sub 2} gate insulator deposited directly onto the organic semiconductor

    SciTech Connect (OSTI)

    Ono, S., E-mail: shimpei@criepi.denken.or.jp [Central Research Institute of Electric Power Industry, Komae, Tokyo 201-8511 (Japan); Häusermann, R. [Central Research Institute of Electric Power Industry, Komae, Tokyo 201-8511 (Japan) [Central Research Institute of Electric Power Industry, Komae, Tokyo 201-8511 (Japan); Laboratory for Solid State Physics, ETH Zurich, Zurich 8093 (Switzerland); Chiba, D. [Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan) [Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan); PRESTO, Japan Science and Technology Agency, 4-1-8 Honcho Kawaguchi, Saitama 322-0012 (Japan); Department of Applied Physics, University of Tokyo, Tokyo 113-8656 (Japan); Shimamura, K.; Ono, T. [Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan)] [Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan); Batlogg, B. [Laboratory for Solid State Physics, ETH Zurich, Zurich 8093 (Switzerland)] [Laboratory for Solid State Physics, ETH Zurich, Zurich 8093 (Switzerland)

    2014-01-06T23:59:59.000Z

    We have produced stable organic field-effect transistors (OFETs) with an ultra-thin HfO{sub 2} gate insulator deposited directly on top of rubrene single crystals by atomic layer deposition (ALD). We find that ALD is a gentle deposition process to grow thin films without damaging rubrene single crystals, as results these devices have a negligibly small threshold voltage and are very stable against gate-bias-stress, and the mobility exceeds 1 cm{sup 2}/V s. Moreover, the devices show very little degradation even when kept in air for more than 2 months. These results demonstrate thin HfO{sub 2} layers deposited by ALD to be well suited as high capacitance gate dielectrics in OFETs operating at small gate voltage. In addition, the dielectric layer acts as an effective passivation layer to protect the organic semiconductor.

  5. In situ observation of oxygen gettering by titanium overlayer on HfO{sub 2}/SiO{sub 2}/Si using high-resolution Rutherford backscattering spectroscopy

    SciTech Connect (OSTI)

    Nakajima, Kaoru; Fujiyoshi, Akira; Ming, Zhao; Suzuki, Motofumi; Kimura, Kenji [Department of Micro Engineering, Kyoto University, Yoshida-Honmachi, Sakyo, Kyoto 606-8501 (Japan)

    2007-09-15T23:59:59.000Z

    Oxygen gettering by Ti overlayer (2-8 nm) on a HfO{sub 2}(3 nm)/SiO{sub 2}(1.5 nm)/Si(001) structure was investigated using high-resolution Rutherford backscattering spectroscopy. After deposition of a thin Ti layer, the interfacial SiO{sub 2} layer is reduced by {approx}0.2 nm and the released oxygen is incorporated in Ti layer. Subsequent annealing at 330 deg. C in UHV causes further reduction by 0.1-0.8 nm depending on the Ti layer thickness. In addition to the reduction of the SiO{sub 2} layer, significant oxygen depletion in the HfO{sub 2} layer was observed for thicker Ti layers after annealing.

  6. Intermixing between HfO{sub 2} and GeO{sub 2} films deposited on Ge(001) and Si(001): Role of the substrate

    SciTech Connect (OSTI)

    Soares, G. V.; Krug, C. [Instituto de Fisica, UFRGS, Porto Alegre, Rio Grande do Sul 91509-900 (Brazil); Miotti, L.; Bastos, K. P.; Lucovsky, G. [Department of Physics, North Carolina State University, Raleigh, North Carolina 27695 (United States); Baumvol, I. J. R. [Instituto de Fisica, UFRGS, Porto Alegre, Rio Grande do Sul 91509-900 (Brazil); Universidade de Caxias do Sul, Caxias do Sul, Rio Grande do Sul 95070-560 (Brazil); Radtke, C. [Instituto de Quimica, UFRGS, Porto Alegre, Rio Grande do Sul 91509-900 (Brazil)

    2011-03-28T23:59:59.000Z

    Thermally driven atomic transport in HfO{sub 2}/GeO{sub 2}/substrate structures on Ge(001) and Si(001) was investigated in N{sub 2} ambient as function of annealing temperature and time. As-deposited stacks showed no detectable intermixing and no instabilities were observed on Si. On Ge, loss of O and Ge was detected in all annealed samples, presumably due to evolution of GeO from the GeO{sub 2}/Ge interface. In addition, hafnium germanate is formed at 600 deg. C. Our data indicate that at 500 deg. C and above HfO{sub 2}/GeO{sub 2} stacks are stable only if isolated from the Ge substrate.

  7. Highly transparent low capacitance plasma enhanced atomic layer deposition Al{sub 2}O{sub 3}-HfO{sub 2} tunnel junction engineering

    SciTech Connect (OSTI)

    El Hajjam, Khalil, E-mail: khalil.el-hajjam@insa-lyon.fr [INL, INSA, UMR CNRS 5270, 7 Avenue Jean Capelle, 69621 Villeurbanne Cedex, France and Institut Interdisciplinaire d'Innovation Technologique (3IT), Université de Sherbrooke, 3000 Boulevard Université, Sherbrooke, J1K OA5, Québec (Canada); Baboux, Nicolas; Calmon, Francis [INL, INSA, UMR CNRS 5270, 7 Avenue Jean Capelle, 69621 Villeurbanne Cedex (France); Souifi, Abdelkader [Laboratoire Nanotechnologies Nanosystèmes (LN2)-CNRS UMI-3463, Université de Sherbrooke, 3000 Boulevard Université, Sherbrooke, J1K OA5, Québec (Canada); Poncelet, Olivier; Francis, Laurent A. [ICTEAM, ELEN, UCL, Place du Levant 3, 1348 Louvain-la-Neuve (Belgium); Ecoffey, Serge; Drouin, Dominique [Laboratoire Nanotechnologies Nanosystèmes (LN2)-CNRS UMI-3463, Université de Sherbrooke, 3000 Boulevard Université, Sherbrooke, J1K OA5, Québec, Canada and Institut Interdisciplinaire d'Innovation Technologique (3IT), Université de Sherbrooke, 3000 Boulevard Université, Sherbrooke, J1K OA5, Québec (Canada)

    2014-01-15T23:59:59.000Z

    The development of metallic single electron transistor (SET) depends on the downscaling and the electrical properties of its tunnel junctions. These tunnel junctions should insure high tunnel current levels, low thermionic current, and low capacitance. The authors use atomic layer deposition to fabricate Al{sub 2}O{sub 3} and HfO{sub 2} thin layers. Tunnel barrier engineering allows the achievement of low capacitance Al{sub 2}O{sub 3} and HfO{sub 2} tunnel junctions using optimized annealing and plasma exposure conditions. Different stacks were designed and fabricated to increase the transparency of the tunnel junction while minimizing thermionic current. This tunnel junction is meant to be integrated in SET to enhance its electrical properties (e.g., operating temperature, I{sub ON}/I{sub OFF} ratio)

  8. In Situ Synchrotron Based X-ray Fluorescence and Scattering Measurements During Atomic Layer Deposition: Initial Growth of HfO2 on Si and Ge Substrates

    SciTech Connect (OSTI)

    K Devloo-Casier; J Dendooven; K Ludwig; G Lekens; J DHaen; C Detavernier

    2011-12-31T23:59:59.000Z

    The initial growth of HfO{sub 2} was studied by means of synchrotron based in situ x-ray fluorescence (XRF) and grazing incidence small angle x-ray scattering (GISAXS). HfO{sub 2} was deposited by atomic layer deposition (ALD) using tetrakis(ethylmethylamino)hafnium and H{sub 2}O on both oxidized and H-terminated Si and Ge surfaces. XRF quantifies the amount of deposited material during each ALD cycle and shows an inhibition period on H-terminated substrates. No inhibition period is observed on oxidized substrates. The evolution of film roughness was monitored using GISAXS. A correlation is found between the inhibition period and the onset of surface roughness.

  9. In situ study of the role of substrate temperature during atomic layer deposition of HfO{sub 2} on InP

    SciTech Connect (OSTI)

    Dong, H.; Santosh, K.C.; Qin, X.; Brennan, B.; McDonnell, S.; Kim, J. [Department of Materials Science and Engineering, University of Texas at Dallas, Richardson, Texas 75080 (United States)] [Department of Materials Science and Engineering, University of Texas at Dallas, Richardson, Texas 75080 (United States); Zhernokletov, D. [Department of Physics, University of Texas at Dallas, Richardson, Texas 75080 (United States)] [Department of Physics, University of Texas at Dallas, Richardson, Texas 75080 (United States); Hinkle, C. L.; Cho, K.; Wallace, R. M. [Department of Materials Science and Engineering, University of Texas at Dallas, Richardson, Texas 75080 (United States) [Department of Materials Science and Engineering, University of Texas at Dallas, Richardson, Texas 75080 (United States); Department of Physics, University of Texas at Dallas, Richardson, Texas 75080 (United States)

    2013-10-21T23:59:59.000Z

    The dependence of the “self cleaning” effect of the substrate oxides on substrate temperature during atomic layer deposition (ALD) of HfO{sub 2} on various chemically treated and native oxide InP (100) substrates is investigated using in situ X-ray photoelectron spectroscopy. The removal of In-oxide is found to be more efficient at higher ALD temperatures. The P oxidation states on native oxide and acid etched samples are seen to change, with the total P-oxide concentration remaining constant, after 10 cycles of ALD HfO{sub 2} at different temperatures. An (NH{sub 4}){sub 2} S treatment is seen to effectively remove native oxides and passivate the InP surfaces independent of substrate temperature studied (200 °C, 250 °C and 300 °C) before and after the ALD process. Density functional theory modeling provides insight into the mechanism of the changes in the P-oxide chemical states.

  10. On the electrical stress-induced oxide-trapped charges in thin HfO{sub 2}/SiO{sub 2} gate dielectric stack

    SciTech Connect (OSTI)

    Samanta, Piyas; Zhu Chunxiang; Chan, Mansun [Department of Electronic and Computer Engineering, The Hong Kong University of Science and Technology, Clear Water Bay Road, Kowloon, Hong Kong (China); Department of Electrical and Computer Engineering, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260 (Singapore); Department of Electronic and Computer Engineering, The Hong Kong University of Science and Technology, Clear Water Bay Road, Kowloon, Hong Kong (China)

    2007-09-10T23:59:59.000Z

    Oxide charge buildup and its generation kinetics during constant voltage stress in TaN/HfO{sub 2}/SiO{sub 2}/p-Si structures have been experimentally investigated. From the oxide charge relaxation experiments, nature and energy location of the as-fabricated intrinsic hole traps in the gate stack have also been determined. Our measurement results indicate that the dispersive proton transport through the interfacial SiO{sub 2} contributes larger than hole trapping in positive charge buildup in the stack. From the bias temperature stress measurement results in both control oxide and HfO{sub 2}/SiO{sub 2} stacks, we have identified overcoordinated [Si{sub 2}=OH]{sup +} centers as the proton-induced defects located in the interfacial SiO{sub 2} layer of the stack. Finally, an empirical equation is proposed to explain the stress-induced oxide positive charge buildup.

  11. Current scaling of axially radiated power in dynamic hohlraums and dynamic hohlraum load design for ZR.

    SciTech Connect (OSTI)

    Mock, Raymond Cecil; Nash, Thomas J.; Sanford, Thomas W. L.

    2007-03-01T23:59:59.000Z

    We present designs for dynamic hohlraum z-pinch loads on the 28 MA, 140 ns driver ZR. The scaling of axially radiated power with current in dynamic hohlraums is reviewed. With adequate stability on ZR this scaling indicates that 30 TW of axially radiated power should be possible. The performance of the dynamic hohlraum load on the 20 MA, 100 ns driver Z is extensively reviewed. The baseline z-pinch load on Z is a nested tungsten wire array imploding onto on-axis foam. Data from a variety of x-ray diagnostics fielded on Z are presented. These diagnostics include x-ray diodes, bolometers, fast x-ray imaging cameras, and crystal spectrometers. Analysis of these data indicates that the peak dynamic radiation temperature on Z is between 250 and 300 eV from a diameter less than 1 mm. Radiation from the dynamic hohlraum itself or from a radiatively driven pellet within the dynamic hohlraum has been used to probe a variety of matter associated with the dynamic hohlraum: the tungsten z-pinch itself, tungsten sliding across the end-on apertures, a titanium foil over the end aperture, and a silicon aerogel end cap. Data showing the existence of asymmetry in radiation emanating from the two ends of the dynamic hohlraum is presented, along with data showing load configurations that mitigate this asymmetry. 1D simulations of the dynamic hohlraum implosion are presented and compared to experimental data. The simulations provide insight into the dynamic hohlraum behavior but are not necessarily a reliable design tool because of the inherently 3D behavior of the imploding nested tungsten wire arrays.

  12. Synchrotron radiation photoemission study of interfacial electronic structure of HfO{sub 2} on In{sub 0.53}Ga{sub 0.47}As(001)-4?×?2 from atomic layer deposition

    SciTech Connect (OSTI)

    Pi, T. W., E-mail: pi@nsrrc.org.tw, E-mail: gkwer@verizon.net, E-mail: raynien@phys.nthu.edu.tw, E-mail: mhong@phys.ntu.edu.tw [National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan (China); Lin, T. D.; Chang, Y. C.; Hong, M., E-mail: pi@nsrrc.org.tw, E-mail: gkwer@verizon.net, E-mail: raynien@phys.nthu.edu.tw, E-mail: mhong@phys.ntu.edu.tw [Graduate Institute of Applied Physics and Department of Physics, National Taiwan University, Taipei 10617, Taiwan (China); Lin, H. Y.; Kwo, J., E-mail: pi@nsrrc.org.tw, E-mail: gkwer@verizon.net, E-mail: raynien@phys.nthu.edu.tw, E-mail: mhong@phys.ntu.edu.tw [Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Wertheim, G. K., E-mail: pi@nsrrc.org.tw, E-mail: gkwer@verizon.net, E-mail: raynien@phys.nthu.edu.tw, E-mail: mhong@phys.ntu.edu.tw [Woodland Consulting, 175 Woodland Ave., Morristown, New Jersey 07960 (United States)

    2014-01-27T23:59:59.000Z

    The growth of a passivating layer on a In{sub 0.53}Ga{sub 0.47}As(001)-4?×?2 surface by atomic-layer deposition of tetrakis[ethylmethylamino]Hafnium (TEMAHf)) followed by the water pulse was investigated by synchrotron radiation photoemission. The Hf atoms maintain four-fold coordination, both after the initial TEMAHf deposition and the subsequent water pulse. The Hf atoms initially bond to the As dangling bonds of the surface As atom located on the edges of the raised ridges. One EMA ligand is removed in this process. Subsequent water exposure substitutes OH ligand for one or more remaining EMA ligands. These in turn react with TEMAHf to form Hf-O-Hf bonds allowing the hafnium oxides to grow. The surface In atoms on the terrace of the raised ridges were partially removed, but none bonded of the precursor atoms. Correlations between the interfacial electronic structure and the electric performance are discussed.

  13. Interface effect on dielectric constant of HfO{sub 2}/Al{sub 2}O{sub 3} nanolaminate films deposited by plasma-enhanced atomic layer deposition

    SciTech Connect (OSTI)

    Park, Pan Kwi; Cha, Eun-Soo; Kang, Sang-Won [Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology, Daejeon 305-701 (Korea, Republic of)

    2007-06-04T23:59:59.000Z

    The effect of the interface between Al{sub 2}O{sub 3} and HfO{sub 2} sublayers on the dielectric constant was investigated in HfO{sub 2}/Al{sub 2}O{sub 3} nanolaminate films deposited using plasma-enhanced atomic layer deposition. After annealing at 700 deg. C, the dielectric constants of the nanolaminate films with a sublayer thickness of 40 A ring or greater were the same as the calculated values for a series of capacitors consisting of amorphous Al{sub 2}O{sub 3} and monoclinic or tetragonal HfO{sub 2}. As the sublayer thickness was reduced to 10 A, the dielectric constant increased up to 17.7 because a thin Hf-O-Al mixture layer, of which the number increases drastically in the nanolaminate films with thin sublayers, is formed at the interface.

  14. Phase characterization and grain size effects of nanophase Y{sub 2}O{sub 3}, ZrO{sub 2} and Y{sub 2}O{sub 3}-ZrO{sub 2} composites produced by the gas-phase condensation technique

    SciTech Connect (OSTI)

    Foster, C.M.; Bai, G.R. [Argonne National Lab., IL (United States); Parker, J.C.; Ali, M.N. [Nanophase Technologies Corp., Darien, IL (United States)

    1992-12-01T23:59:59.000Z

    Nanophase (n-) ZrO{sub 2} was produce in its pure and partially stabilized form by the gas-phase condensation method. The material was examined by x-ray diffraction and Raman scattering to obtain information on the structural evolution of the material during sintering. Two types of Y{sub 2}O{sub 3} doped ZrO{sub 2} doped ZrO{sub 2} nanophase materials were made, one by co-deposition of n-Y{sub 2}O{sub 3} and n-ZrO{sub 2}. We have determined that the co-deposition process is the most effect means of doping the n-ZrO{sub 2}.

  15. Phase characterization and grain size effects of nanophase Y[sub 2]O[sub 3], ZrO[sub 2] and Y[sub 2]O[sub 3]-ZrO[sub 2] composites produced by the gas-phase condensation technique

    SciTech Connect (OSTI)

    Foster, C.M.; Bai, G.R. (Argonne National Lab., IL (United States)); Parker, J.C.; Ali, M.N. (Nanophase Technologies Corp., Darien, IL (United States))

    1992-12-01T23:59:59.000Z

    Nanophase (n-) ZrO[sub 2] was produce in its pure and partially stabilized form by the gas-phase condensation method. The material was examined by x-ray diffraction and Raman scattering to obtain information on the structural evolution of the material during sintering. Two types of Y[sub 2]O[sub 3] doped ZrO[sub 2] doped ZrO[sub 2] nanophase materials were made, one by co-deposition of n-Y[sub 2]O[sub 3] and n-ZrO[sub 2]. We have determined that the co-deposition process is the most effect means of doping the n-ZrO[sub 2].

  16. Interfacial Layer Growth Condition Dependent Electrical Conduction in HfO2/SiO2 Heterostructured Thin Films

    SciTech Connect (OSTI)

    Sahoo, S. K.; Misra, D.

    2012-01-01T23:59:59.000Z

    The electrical conduction mechanism contributing to the leakage current at different field regions has been studied in this work. The current-voltage (I-V) measurement of TiN/HfO{sub 2}/SiO{sub 2}/P-Si nMOS capacitor has been taken for two different interfacial layer (SiO{sub 2}) growth conditions such as in situ steam grown (ISSG) and chemical processes. It is observed that Poole-Frenkel mechanism is the dominant conduction mechanism in high field region whereas Ohmic conduction is dominant in the low field region. Also it is seen that the gate leakage current is reduced for the devices having chemically grown interfacial layer compared to that of ISSG devices. Both trap energy level ({phi}{sub t}) and activation energy (E{sub a}) increase in the chemically grown interfacial layer devices for the Poole-Frenkel and Ohmic conduction mechanisms respectively in comparison to ISSG devices. Trap energy level ({phi}{sub t}) of {approx} 0.2 eV, obtained from Poole-Frenkel mechanism indicates that the doubly ionized oxygen vacancies (V{sup 2-}) are the active defects and are contributing to the leakage current in these devices.

  17. Energy band alignment of atomic layer deposited HfO{sub 2} oxide film on epitaxial (100)Ge, (110)Ge, and (111)Ge layers

    SciTech Connect (OSTI)

    Hudait, Mantu K.; Zhu Yan [Advanced Devices and Sustainable Energy Laboratory (ADSEL), Bradley Department of Electrical and Computer Engineering, Virginia Tech, Blacksburg, Virginia 24061 (United States)

    2013-03-21T23:59:59.000Z

    Crystallographically oriented epitaxial Ge layers were grown on (100), (110), and (111)A GaAs substrates by in situ growth process using two separate molecular beam epitaxy chambers. The band alignment properties of atomic layer hafnium oxide (HfO{sub 2}) film deposited on crystallographically oriented epitaxial Ge were investigated using x-ray photoelectron spectroscopy (XPS). Valence band offset, {Delta}E{sub v} values of HfO{sub 2} relative to (100)Ge, (110)Ge, and (111)Ge orientations were 2.8 eV, 2.28 eV, and 2.5 eV, respectively. Using XPS data, variation in valence band offset, {Delta}E{sub V}(100)Ge>{Delta}E{sub V}(111)Ge>{Delta}E{sub V}(110)Ge, was obtained related to Ge orientation. Also, the conduction band offset, {Delta}E{sub c} relation, {Delta}E{sub c}(110)Ge>{Delta}E{sub c}(111)Ge>{Delta}E{sub c}(100)Ge related to Ge orientations was obtained using the measured bandgap of HfO{sub 2} on each orientation and with the Ge bandgap of 0.67 eV. These band offset parameters for carrier confinement would offer an important guidance to design Ge-based p- and n-channel metal-oxide field-effect transistor for low-power application.

  18. Effect of Si substrate on interfacial SiO{sub 2} scavenging in HfO{sub 2}/SiO{sub 2}/Si stacks

    SciTech Connect (OSTI)

    Li, Xiuyan, E-mail: xiuyan@adam.t.u-tokyo.ac.jp; Yajima, Takeaki; Nishimura, Tomonori; Nagashio, Kosuke; Toriumi, Akira [Department of Materials Engineering, The University of Tokyo, 7-3-1 Hongo, Tokyo 113-8656 (Japan)

    2014-11-03T23:59:59.000Z

    The scavenging kinetics of an ultra-thin SiO{sub 2} interface layer (SiO{sub 2}-IL) in an HfO{sub 2}/SiO{sub 2}/Si stack is discussed by focusing on the substrate effect in addition to oxygen diffusion. {sup 18}O tracing experiments demonstrate that the O-atom moves from the SiO{sub 2}-IL to the HfO{sub 2} layer during scavenging. SiO{sub 2}-IL scavenging with various substrates (Si, SiC, and sapphire) has been found to be significantly different, which suggests that the Si in the substrate is also necessary to continuously cause the scavenging. Based on these findings and thermodynamic considerations, a kinetic model where oxygen vacancy (V{sub O}) transferred from the HfO{sub 2} reacts with the SiO{sub 2}, which is in contact with the Si-substrate, is proposed for the SiO{sub 2}-IL scavenging.

  19. Formation of the dopant-oxygen vacancy complexes and its influence on the photoluminescence emissions in Gd-doped HfO{sub 2}

    SciTech Connect (OSTI)

    Wang, L. G.; Tu, H. L.; Xiong, Y. H.; Du, J.; Wang, J. W.; Huang, G. J. [General Research Institute for Nonferrous Metals, Beijing 100088 (China); Xiao, W. [General Research Institute for Nonferrous Metals, Beijing 100088 (China); University of Science and Technology Beijing, Beijing 100083 (China)

    2014-09-28T23:59:59.000Z

    Rare earth doping is widely used to improve the desired properties of high-k dielectric oxides. However, whether rare earth doping can suppress the formation of oxygen vacancies is still debated. By using the first-principles calculations with the generalized gradient approximation and more advanced hybrid functional, we have investigated the structural and electronic properties of the dopant-oxygen vacancy complexes in Gd-doped HfO{sub 2}. Our calculations indicate that the Gd dopants interacting with oxygen vacancies can substantially shift up the V{sub O} energy states towards the conduction band edge. This together with other effects, such as capturing the localized electrons at the oxygen vacancy by Gd dopants and suppressing the randomicity of oxygen vacancy formation, improves the reliability of the devices made from Gd-doped HfO{sub 2}. Based on our calculated results, we have presented an explanation for the experimentally observed decrease of the V{sub O}-related photoluminescence intensities upon Gd doping in HfO{sub 2}.

  20. Realization of high-quality HfO{sub 2} on In{sub 0.53}Ga{sub 0.47}As by in-situ atomic-layer-deposition

    SciTech Connect (OSTI)

    Lin, T. D.; Hong, M. [Graduate Institute of Applied Physics and Department of Physics, National Taiwan University, Taipei 10617, Taiwan (China); Chang, Y. H. [Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Lin, C. A.; Huang, M. L.; Lee, W. C. [Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Kwo, J. [Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Center for Condensed Matter Sciences, National Taiwan University, Taipei 10617, Taiwan (China)

    2012-04-23T23:59:59.000Z

    High {kappa} dielectric of HfAlO/HfO{sub 2} was an in-situ atomic-layer-deposited directly on molecular beam epitaxy grown In{sub 0.53}Ga{sub 0.47}As surface without using pre-treatments or interfacial passivation layers, where HfAlO (HfO{sub 2}:Al{sub 2}O{sub 3} {approx} 4:1) with high re-crystallization temperature was employed as the top oxide layer. The HfAlO ({approx}4.5 nm)/HfO{sub 2} (0.8 nm)/In{sub 0.53}Ga{sub 0.47}As metal oxide semiconductor capacitors have exhibited an oxide/In{sub 0.53}Ga{sub 0.47}As interface free of arsenic-related defective bonding, thermodynamic stability at 800 deg. C, and low leakage current densities of <10{sup -7} A/cm{sup 2} at {+-}1 MV/cm. The interfacial trap density (D{sub it}) spectra in absence of mid-gap peaks were obtained by temperature-dependent capacitance and conductance with D{sub it}'s of 2-3 x 10{sup 12} eV{sup -1} cm{sup -2} below and 6-12 x 10{sup 11} eV{sup -1} cm{sup -2} above the mid-gap of In{sub 0.53}Ga{sub 0.47}As, respectively. An equivalent oxide thickness of less than 1 nm has been achieved by reducing the HfAlO thickness to {approx}2.7 nm with the same initial HfO{sub 2} thickness of {approx}0.8 nm.

  1. Effects of in situ N{sub 2} plasma treatment on etch of HfO{sub 2} in inductively coupled Cl{sub 2}/N{sub 2} plasmas

    SciTech Connect (OSTI)

    Lin Chaung; Leou, K.-C.; Fan, Y.-C.; Li, T.-C.; Chang, K.-H.; Lee, L.-S.; Tzeng, P.-J. [Department of Engineering and System Science, National Tsing Hua University, Hsinchu 30043, Taiwan (China); Electronic Research and Service Organization, Industrial Technology Research Institute, Hsinchu 30043, Taiwan (China)

    2007-05-15T23:59:59.000Z

    The etch selectivity of HfO{sub 2} to Si reported to date is poor. To improve the selectivity, one needs to either increase the etch rate of HfO{sub 2} or decrease the etch rate of Si. In this work, the authors investigate the etch selectivity of HfO{sub 2} in Cl{sub 2}/N{sub 2} plasmas. In particular, the effects of in situ N{sub 2} plasma treatment of HfO{sub 2} and Si were investigated. The silicon substrate was exposed to nitrogen plasma and was nitrided, which was confirmed by x-ray photoelectron spectroscopy. The nitrided Si etching was suppressed in Cl{sub 2}/N{sub 2} plasmas. The effectiveness of nitridation was studied with varying the plasma power, bias power, pressure, and N{sub 2} plasma exposure time. The results show that the etch resistance increased with increased power and decreased pressure. A minimum exposure time was required to obtain etch resistant property. The applied bias power increased the etch rate of Si substrate, so it should not be used during N{sub 2} plasma treatment. Fortunately, the etch rate of HfO{sub 2} was increased by the nitridation process. Therefore, HfO{sub 2}/Si selectivity can be improved by nitridation and became higher than 5 under proper exposure condition.

  2. A study of the anodic polarization behavior of Zr(50)Cu(40-x)Al(10)Pd(x) BMG with scanning Auger microanalysis

    SciTech Connect (OSTI)

    Green, Brandice [ORNL; Meyer III, Harry M [ORNL; Benson, Roberto S [ORNL; Yokoyama, Y [Institute for Materials Research; Liaw, Peter K [University of Tennessee, Knoxville (UTK); Liu, Chain T [ORNL

    2008-01-01T23:59:59.000Z

    The anodic-polarization behaviors of Zr50Cu40-XAl10PdX (x = 0 and 7 atomic %) BMGs were investigated in 0.6 M NaCl electrolytes. Initial anodic polarization of both alloys yielded regions where small increases in the applied potential induced significant increases in the current density. Continued polarization of both BMGs resulted in diffusion controlled regimes. However, the limiting diffusion current density of Zr50Cu33Al10Pd7 was higher than that of Zr50Cu40Al10. Scanning Auger microanalysis was used to investigate the oxide formed during polarization and to analyze the chemistry within corrosion pits. The pits formed on both BMGs were enriched with Cu and Cl. Corrosion pits on Zr50Cu33Al10Pd7 were additionally enriched with Pd. A corrosion mechanism relating to the formation of CuCl and Cu2O is proposed based on both the polarization and microanalysis results.

  3. Brazing ZrO{sub 2} ceramic to Ti–6Al–4V alloy using NiCrSiB amorphous filler foil: Interfacial microstructure and joint properties

    SciTech Connect (OSTI)

    Cao, J., E-mail: cao_jian@hit.edu.cn [Shandong Provincial Key Laboratory of Special Welding Technology, Harbin Institute of Technology at Weihai, Weihai 264209 (China); State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001 (China); Song, X.G., E-mail: song_xiaoguohit@yahoo.com.cn [Shandong Provincial Key Laboratory of Special Welding Technology, Harbin Institute of Technology at Weihai, Weihai 264209 (China); State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001 (China); Li, C., E-mail: li_chun1989@yahoo.cn [State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001 (China); Zhao, L.Y., E-mail: Zhao_ly@163.com [State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001 (China); Feng, J.C., E-mail: feng_jicai@163.com [Shandong Provincial Key Laboratory of Special Welding Technology, Harbin Institute of Technology at Weihai, Weihai 264209 (China); State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001 (China)

    2013-07-15T23:59:59.000Z

    Reliable brazing of ZrO{sub 2} ceramic and Ti–6Al–4V alloy was achieved using NiCrSiB amorphous filler foil. The interfacial microstructure of ZrO{sub 2}/Ti–6Al–4V joints was characterized by scanning electron microscope, energy dispersive spectrometer and micro-focused X-ray diffractometer. The effects of brazing temperature on the interfacial microstructure and joining properties of brazed joints were investigated in detail. Active Ti of Ti–6Al–4V alloy dissolved into molten filler metal and reacted with ZrO{sub 2} ceramic to form a continuous TiO reaction layer, which played an important role in brazing. Various reaction phases including Ti{sub 2}Ni, Ti{sub 5}Si{sub 3} and ?-Ti were formed in brazed joints. With an increasing of brazing temperature, the TiO layer thickened gradually while the Ti{sub 2}Ni amount reduced. Shear test indicated that brazed joints tend to fracture at the interface between ZrO{sub 2} ceramic and brazing seam or Ti{sub 2}Ni intermetallic layer. The maximum average shear strength reached 284.6 MPa when brazed at 1025 °C for 10 min. - Graphical Abstract: Interfacial microstructure of ZrO{sub 2}/TC4 joint brazed using NiCrSiB amorphous filler foil was: ZrO{sub 2}/TiO/Ti{sub 2}Ni + ?-Ti + Ti{sub 5}Si{sub 3}/?-Ti/Widmanstätten structure/TC4. - Highlights: • Brazing of ZrO{sub 2} ceramic and Ti-6Al-4V alloy was achieved. • Interfacial microstructure was TiO/Ti{sub 2}Ni + ? + Ti{sub 5}Si{sub 3}/?/Widmanstätten structure. • The formation of TiO produced the darkening effect of ZrO{sub 2} ceramic. • The highest joining strength of 284.6MPa was obtained.

  4. Characterization of self-propagating formation reactions in Ni/Zr multilayered foils using reaction heats, velocities, and temperature-time profiles

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Barron, S. C.; Knepper, R.; Walker, N.; Weihs, T. P.

    2011-01-11T23:59:59.000Z

    We report on intermetallic formation reactions in vapor-deposited multilayered foils of Ni/Zr with 70 nm bilayers and overall atomic ratios of Ni:Zr, 2 Ni:Zr, and 7 Ni:2 Zr. The sequence of alloy phase formation and the stored energy is evaluated at slow heating rates (~1 K/s) using differential scanning calorimetry (DSC) traces to 725ºC. All three chemistries initially form a Ni-Zr amorphous phase which crystallizes first to the intermetallic NiZr. The heat of reaction to the final phase is 34-36 kJ/mol atom for all chemistries. Intermetallic formation reactions are also studied at rapid heating rates (greater than 105 K/s) in high temperature, self-propagating reactions which can be ignited in these foils by an electric spark. We find that reaction velocities and maximum reaction temperatures (Tmax) are largely independent of foil chemistry at 0.6 ± 0.1 m/s and 1220 ± 50 K, respectively, and that the measured Tmax is more than 200 K lower than predicted adiabatic temperatures (Tad). The difference between Tmax and Tad is explained by the prediction that transformation to the final intermetallic phases occurs after Tmax and results in the release of 20-30 % of the total heat of reaction and a delay in rapid cooling.

  5. Behavior of the electroless composite films plated from a Ni-P bath with metallic dispersion of Zr and Nb powders

    SciTech Connect (OSTI)

    Osaka, T.; Koiwa, I.; Usuda, M.; Arai, K.; Saito, I.

    1989-04-01T23:59:59.000Z

    An electroless Ni-Zr-P composite film and a Ni-Nb-P composite film were plated and their heat-treating behaviors were investigated. The addition of 20g dm/sup -3/ of metallic powder resulted in a composite film that contained 21.2 weight percent (w/o) of Zr. (13.8 atom percent (a/o)), or 4.8 w/o of Nb. (2.9 a/o), respectively. Both metallic powders were dispersed uniformly throughout the film. The metallic Ni formed by the crystallization on the Ni-P matrix diffused into the metallic powders, and the amorphous Ni-Zr and Ni-Nb phases were formed by heat-treatment at 500/sup 0/ or 300/sup 0/C. Some parts of the amorphous Ni-Zr phases and the metallic Ni phases combined to form intermetallic compounds by heat-treatment at 600/sup 0/C. The nickel-rich parts of the amorphous Ni-Nb phase were converted into a metastable Ni-Nb phase (zeta phase) or a Ni-Nb solid solution by heat-treatment at 700/sup 0/C. The longer heating time at 400/sup 0/C increased the amount of the Ni-Zr amorphous phase: however, it decreased the reactivity of the amorphous Ni-Zr phase. The same heat-treatment of 400/sup 0/C did not give the considerable change on the amorphous Ni-Nb phase.

  6. Phase Characteristics of a Number of U-Pu-Am-Np-Zr Metallic Alloys for Use as Fast Reactor Fuels

    SciTech Connect (OSTI)

    Douglas E. Burkes; J. Rory Kennedy; Thomas Hartmann; Cynthia A. Papesch; Denis D. Keiser, Jr.

    2010-01-01T23:59:59.000Z

    Metallic fuel alloys consisting of uranium, plutonium, and zirconium with minor additions of americium and neptunium are under evaluation for potential use to transmute long-lived transuranic actinide isotopes in fast reactors. A series of test designs for the Advanced Fuel Cycle Initiative (AFCI) have been irradiated in the Advanced Test Reactor (ATR), designated as the AFC-1 and AFC-2 designs. Metal fuel compositions in these designs have included varying amounts of U, Pu, Zr, and minor actinides (Am, Np). Investigations into the phase behavior and relationships based on the alloy constituents have been conducted using x-ray diffraction and differential thermal analysis. Results of these investigations, along with proposed relationships between observed behavior and alloy composition, are provided. In general, observed behaviors can be predicted by a ternary U-Pu-Zr phase diagram, with transition temperatures being most dependent on U content. Furthermore, the enthalpy associated with transitions is strongly dependent on the as-cast microstructural characteristics.

  7. Thermal conductivity profile determination in proton-irradiated ZrC by spatial and frequency scanning thermal wave methods

    SciTech Connect (OSTI)

    Jensen, C. [GRESPI, Multiscale Thermophysics Lab., Université de Reims Champagne-Ardenne URCA, Moulin de la Housse BP 1039, Reims 51687 (France) [GRESPI, Multiscale Thermophysics Lab., Université de Reims Champagne-Ardenne URCA, Moulin de la Housse BP 1039, Reims 51687 (France); Department of Mechanical and Aerospace Engineering, Utah State University, Logan, Utah 84322 (United States); Chirtoc, M.; Horny, N.; Antoniow, J. S.; Pron, H. [GRESPI, Multiscale Thermophysics Lab., Université de Reims Champagne-Ardenne URCA, Moulin de la Housse BP 1039, Reims 51687 (France)] [GRESPI, Multiscale Thermophysics Lab., Université de Reims Champagne-Ardenne URCA, Moulin de la Housse BP 1039, Reims 51687 (France); Ban, H. [Department of Mechanical and Aerospace Engineering, Utah State University, Logan, Utah 84322 (United States)] [Department of Mechanical and Aerospace Engineering, Utah State University, Logan, Utah 84322 (United States)

    2013-10-07T23:59:59.000Z

    Using complementary thermal wave methods, the irradiation damaged region of zirconium carbide (ZrC) is characterized by quantifiably profiling the thermophysical property degradation. The ZrC sample was irradiated by a 2.6 MeV proton beam at 600 °C to a dose of 1.75 displacements per atom. Spatial scanning techniques including scanning thermal microscopy (SThM), lock-in infrared thermography (lock-in IRT), and photothermal radiometry (PTR) were used to directly map the in-depth profile of thermal conductivity on a cross section of the ZrC sample. The advantages and limitations of each system are discussed and compared, finding consistent results from all techniques. SThM provides the best resolution finding a very uniform thermal conductivity envelope in the damaged region measuring ?52 ± 2 ?m deep. Frequency-based scanning PTR provides quantification of the thermal parameters of the sample using the SThM measured profile to provide validation of a heating model. Measured irradiated and virgin thermal conductivities are found to be 11.9 ± 0.5 W m{sup ?1} K{sup ?1} and 26.7 ±1 W m{sup ?1} K{sup ?1}, respectively. A thermal resistance evidenced in the frequency spectra of the PTR results was calculated to be (1.58 ± 0.1) × 10{sup ?6} m{sup 2} K W{sup ?1}. The measured thermal conductivity values compare well with the thermal conductivity extracted from the SThM calibrated signal and the spatially scanned PTR. Combined spatial and frequency scanning techniques are shown to provide a valuable, complementary combination for thermal property characterization of proton-irradiated ZrC. Such methodology could be useful for other studies of ion-irradiated materials.

  8. Dynamic study on fusion reactions for $^{40,48}$Ca+$^{90,96}$Zr around Coulomb barrier

    E-Print Network [OSTI]

    Ning Wang; Xizhen Wu; Zhuxia Li

    2003-01-09T23:59:59.000Z

    By using the updated improved Quantum Molecular Dynamics model in which a surface-symmetry potential term has been introduced for the first time, the excitation functions for fusion reactions of $^{40,48}$Ca+$^{90,96}$Zr at energies around the Coulomb barrier have been studied. The experimental data of the fusion cross sections for $^{40}$Ca+$^{90,96}$Zr have been reproduced remarkably well without introducing any new parameters. The fusion cross sections for the neutron-rich fusion reactions of $^{48}$Ca+$^{90,96}$Zr around the Coulomb barrier are predicted to be enhanced compared with a non-neutron-rich fusion reaction. In order to clarify the mechanism of the enhancement of the fusion cross sections for neutron-rich nuclear fusions, we pay a great attention to study the dynamic lowering of the Coulomb barrier during a neck formation. The isospin effect on the barrier lowering is investigated. It is interesting that the effect of the projectile and target nuclear structure on fusion dynamics can be revealed to a certain extent in our approach. The time evolution of the N/Z ratio at the neck region has been firstly illustrated. A large enhancement of the N/Z ratio at neck region for neutron-rich nuclear fusion reactions is found.

  9. 85R.A. Calvo and S.K. D'Mello (eds.), New Perspectives on Affect and Learning Technologies, Explorations in the Learning Sciences, Instructional Systems and Performance Technologies 3,

    E-Print Network [OSTI]

    Young, R. Michael

    85R.A. Calvo and S.K. D'Mello (eds.), New Perspectives on Affect and Learning Technologies to which he or she is motivated to continue with the learning process (Kort, Reilly, & Picard, 2001; Picard work (Arroyo, Woolf, Royer, & Tai, 2009; Chaffar & Frasson, 2004; D'Mello et al., 2008; Forbes- Riley

  10. Citation: Myers, R.A. and C.A. Ottensmeyer.(2005, in press). Extinction Risk in Marine Species. in Norse, E.A. and L.B. Crowder, eds. Marine Conservation Biology: The Science of Maintaining the Sea's Biodiversity. Island

    E-Print Network [OSTI]

    Myers, Ransom A.

    Citation: Myers, R.A. and C.A. Ottensmeyer.(2005, in press). Extinction Risk in Marine Species's Biodiversity. Island Press, Washington DC (USA) Chapter 5 Extinction Risk in Marine Species Ransom A. Myers C resources seemed inexhaustible, its capacity boundless. Marine species have even been considered "extinction

  11. Tsovaltzi, D., Weinberger, A., Scheuer, O., Dragon, T. & McLaren, B.M., (2012). Argument diagrams in Facebook: Facilitating the formation of scientifically sound opinions. In: A. Ra-

    E-Print Network [OSTI]

    McLaren, Bruce Martin

    2012-01-01T23:59:59.000Z

    in Facebook: Facilitating the formation of scientifically sound opinions. In: A. Ra- venscroft, S. Lindstaedt in Facebook: Facilitating the Formation of Scientifically Sound Opinions Dimitra Tsovaltzi, Armin Weinberger Dimitra.tsovalzi@mx.uni-saarland.de Students use Facebook to organize their classroom experiences [1

  12. Observation of the chiral magnetic effect in ZrTe5

    E-Print Network [OSTI]

    Qiang Li; Dmitri E. Kharzeev; Cheng Zhang; Yuan Huang; I. Pletikosic; A. V. Fedorov; R. D. Zhong; J. A. Schneeloch; G. D. Gu; T. Valla

    2014-12-19T23:59:59.000Z

    The chiral magnetic effect is the generation of electric current induced by chirality imbalance in the presence of magnetic field. It is a macroscopic manifestation of the quantum anomaly in relativistic field theory of chiral fermions (massless spin $1/2$ particles with a definite projection of spin on momentum) -- a dramatic phenomenon arising from a collective motion of particles and antiparticles in the Dirac sea. The recent discovery of Dirac semimetals with chiral quasi-particles opens a fascinating possibility to study this phenomenon in condensed matter experiments. Here we report on the first observation of chiral magnetic effect through the measurement of magneto-transport in zirconium pentatelluride, ZrTe_5. Our angle-resolved photoemission spectroscopy experiments show that this material's electronic structure is consistent with a 3D Dirac semimetal. We observe a large negative magnetoresistance when magnetic field is parallel with the current. The measured quadratic field dependence of the magnetoconductance is a clear indication of the chiral magnetic effect. The observed phenomenon stems from the effective transmutation of Dirac semimetal into a Weyl semimetal induced by the parallel electric and magnetic fields that represent a topologically nontrivial gauge field background.

  13. Synthesis, crystal structure, and properties of the rhombohedral modification of the thiospinel CuZr{sub 1.86(1)}S{sub 4}

    SciTech Connect (OSTI)

    Dong, Yongkwan [Baker Laboratory, Department of Chemistry, Cornell University, Ithaca, NY 14853-1301 (United States); McGuire, Michael A. [Department of Physics, Cornell University, Ithaca, NY 14853-1301 (United States); Yun, Hoseop, E-mail: hsyun@ajou.ac.k [Division of Energy Research System and Department of Chemistry, Ajou University, Suwon 442-749 (Korea, Republic of); DiSalvo, Francis J., E-mail: fjd3@cornell.ed [Baker Laboratory, Department of Chemistry, Cornell University, Ithaca, NY 14853-1301 (United States)

    2010-03-15T23:59:59.000Z

    The rhombohedral modification of the thiospinel, CuZr{sub 1.86(1)}S{sub 4}, has been synthesized by the reaction of the constituent elements in an alkali metal halide flux and structurally characterized by single crystal X-ray diffraction techniques. The title compound crystallizes in the rhombohedral space group D{sub 3d}{sup 5}-R3-barm (no. 166, a=7.3552(2) A, c=35.832(2) A, V=1678.76(13) A{sup 3}, Z=12, and R/wR=0.0239/0.0624). The structure is composed of close packed S layers, with a stacking order of ...ABCBCABABCACAB....along the c axis. The Zr and Cu atoms occupy the octahedral and tetrahedral holes between S layers, respectively. Three different kinds of S-M-S layers exist in the structure: layer I has fully occupied Zr and Cu sites, layer II has fully occupied Zr sites but no Cu, and layer III has partially occupied Zr and fully occupied Cu sites. Transport and optical properties indicate that the title compound is a small band gap (1.26 eV) n-type semiconductor. - Graphical abstract: The projected view of the rhombohedral modification, CuZr{sub 1.86(1)}S{sub 4}, down the [100] direction. Large letters denote the packing sequence of the S atoms (yellow circles) along the c axis. Zr (black circles) and Cu (red circles) atoms occupy the octahedral and tetrahedral holes, respectively, between close packed S layers.

  14. Negative effect of crystallization on the mechanism of laser damage in a HfO{sub 2}/SiO{sub 2} multilayer

    SciTech Connect (OSTI)

    Tateno, Ryo [Shimadzu Corporation, 1, Nishinokyo-Kuwabaracho Nakagyo-ku, Kyoto 604-8511 (Japan); Okada, Hajime; Otobe, Tomohito; Kawase, Keigo; Koga, James K.; Kosuge, Atsushi; Nagashima, Keisuke; Sugiyama, Akira [Kansai Photon Science Institute, Japan Atomic Energy Agency, 8-1-7 Umemidai, Kizugawa-shi, Kyoto 619-0215 (Japan); Kashiwagi, Kunihiro [Department of Electrical and Communication Engineering, Faculty of Engineering, Toyo University, 2100, Kujirai Kawagoe-shi, Saitama 350-8585 (Japan)

    2012-12-15T23:59:59.000Z

    Elucidation of the mechanisms of laser damage is indispensable in realizing high resistance mirrors for the next generation of ultra-short pulse high intensity lasers. In this study, the surface and a section of the laser-damaged area of a laser mirror were observed with a laser microscope and a transmission electron microscope (cross-sectional TEM), respectively. A grain boundary of HfO{sub 2} microcrystal was observed in the damaged area. This observation and an evaluation of the mirror's damage resistance showed that the formation of crystals in the multilayer mirror is one of the major determinants of damage resistance.

  15. Looking for footprint of bulk metallic glass in electronic and phonon heat capacities of Cu{sub 55}Hf{sub 45?x}Ti{sub x} alloys

    SciTech Connect (OSTI)

    Remenyi, G. [Institut Néel, Université Grenoble Alpes, F-38042 Grenoble (France); CNRS, Institut Néel, F-38042 Grenoble (France); Biljakovi?, K. [CNRS, Institut Néel, F-38042 Grenoble (France); Institute of Physics, Bijeni?ka c. 46, P.O. Box 304, HR-10001 Zagreb (Croatia); Starešini?, D.; Dominko, D., E-mail: ddominko@ifs.hr [Institute of Physics, Bijeni?ka c. 46, P.O. Box 304, HR-10001 Zagreb (Croatia); Risti?, R. [Department of Physics, Trg Lj. Gaja 6, HR-31000 Osijek (Croatia); Babi?, E. [Department of Physics, Faculty of Science, Bijeni?ka c. 32, HR-10000 Zagreb (Croatia); Figueroa, I. A. [Institute for Materials Research-UNAM, Ciudad Universitaria Coyoacan, C.P. 04510 Mexico D.F. (Mexico); Davies, H. A. [Department of Engineering Materials, University of Sheffield, Sheffield S1 3JD (United Kingdom)

    2014-04-28T23:59:59.000Z

    We report on the heat capacity investigation of Cu{sub 55}Hf{sub 45?x}Ti{sub x} metallic glasses. The most appropriate procedure to estimate low temperature electronic and phonon contributions has been determined. Both contributions exhibit monotonous Ti concentration dependence, demonstrating that there is no relation of either the electron density of states at the Fermi level or the Debye temperature to the increased glass forming ability in the Ti concentration range x?=?15–30. The thermodynamic parameters (e.g., reduced glass temperature) remain better indicators in assessing the best composition for bulk metallic glass formation.

  16. Localization of vacancies and mobility of lithium ions in Li{sub 2}ZrO{sub 3} as obtained by {sup 6,7}Li NMR

    SciTech Connect (OSTI)

    Baklanova, Ya. V., E-mail: baklanovay@ihim.uran.ru [Institute of Solid State Chemistry, Ural Branch of the Russian Academy of Sciences, 91 Pervomaiskaya str., 620990 Ekaterinburg (Russian Federation); Arapova, I. Yu.; Buzlukov, A.L.; Gerashenko, A.P.; Verkhovskii, S.V.; Mikhalev, K.N. [Institute of Metal Physics, Ural Branch of the Russian Academy of Sciences, 18 Kovalevskaya str., 620990 Ekaterinburg (Russian Federation); Denisova, T.A.; Shein, I.R.; Maksimova, L.G. [Institute of Solid State Chemistry, Ural Branch of the Russian Academy of Sciences, 91 Pervomaiskaya str., 620990 Ekaterinburg (Russian Federation)

    2013-12-15T23:59:59.000Z

    The {sup 6,7}Li NMR spectra and the {sup 7}Li spin–lattice relaxation rate were measured on polycrystalline samples of Li{sub 2}ZrO{sub 3}, synthesized at 1050 K and 1300 K. The {sup 7}Li NMR lines were attributed to corresponding structural positions of lithium Li1 and Li2 by comparing the EFG components with those obtained in the first-principles calculations of the charge density in Li{sub 2}ZrO{sub 3}. For both samples the line width of the central {sup 7}Li transition and the spin–lattice relaxation time decrease abruptly at the temperature increasing above ?500 K, whereas the EFG parameters are averaged (??{sub Q}?=42 (5) kHz) owing to thermally activated diffusion of lithium ions. - Graphical abstract: Path of lithium ion hopping in lithium zirconate Li{sub 2}ZrO{sub 3}. - Highlights: • Polycrystalline samples Li{sub 2}ZrO{sub 3} with monoclinic crystal structure synthesized at different temperatures were investigated by {sup 6,7}Li NMR spectroscopy. • Two {sup 6,7}Li NMR lines were attributed to the specific structural positions Li1 and Li2. • The distribution of vacancies was clarified for both lithium sites. • The activation energy and pathways of lithium diffusion in Li{sub 2}ZrO{sub 3} were defined.

  17. Interfacial analysis of the ex-situ reinforced phase of a laser spot welded Zr-based bulk metallic glass composite

    SciTech Connect (OSTI)

    Wang, Huei-Sen, E-mail: huei@isu.edu.tw [Department of Materials Science and Engineering, I-Shou University, Kaohsiung, 84001, Taiwan (China); Department of Chemical and Materials Engineering, National University of Kaohsiung, 81148, Kaohsiung, Taiwan (China); Chen, Hou-Guang [Department of Materials Science and Engineering, I-Shou University, Kaohsiung, 84001, Taiwan (China); Jang, Jason Shian-Ching [Institute of Materials Science and Engineering and Department of Mechanical Engineering, National Central University, Chung-Li 32001, Taiwan (China); Lin, Dong-Yih [Department of Chemical and Materials Engineering, National University of Kaohsiung, 81148, Kaohsiung, Taiwan (China); Gu, Jhen-Wang [Department of Materials Science and Engineering, I-Shou University, Kaohsiung, 84001, Taiwan (China)

    2013-12-15T23:59:59.000Z

    To study the interfacial reaction of the ex-situ reinforced phase (Ta) of a Zr-based ((Zr{sub 48}Cu{sub 36}Al{sub 8}Ag{sub 8})Si{sub 0.75} + Ta{sub 5}) bulk metallic glass composite after laser spot welding, the interfacial regions of the reinforced phases located at specific zones in the welds including the parent material, weld fusion zone and heat affected zone were investigated. Specimen preparation from the specific zones for transmission electron microscopy analysis was performed using the focused ion beam technique. The test results showed that the reinforced phases in the parent material, weld fusion zone and heat affected zone were all covered by an interfacial layer. From microstructure analysis, and referring to the phase diagram, it was clear that the thin layers are an intermetallic compound ZrCu phase. However, due to their different formation processes, those layers show the different morphologies or thicknesses. - Highlights: • An ex-situ Zr-based BMG composite was laser spot welded. • The interfacial regions of the RPs located at PM, WFZ and HAZ were investigated. • The RPs in the PM, WFZ and HAZ were all covered by a ZrCu interfacial layer. • Due to different formation processes, those layers show the different morphology.

  18. Synthesis, Crystal Structure, and Properties of the Rhomboheral Modification of the Thiospinel CuZr1.86(1)S4

    SciTech Connect (OSTI)

    Dong, Yongkwan [Cornell University; McGuire, Michael A [ORNL; Hoseop, Yun [Ajou University, Suwon, South Korea; DiSalvo, Francis J. [Cornell University

    2009-01-01T23:59:59.000Z

    The rhombohedral modification of the thiospinel, CuZr{sub 1.86(1)}S{sub 4}, has been synthesized by the reaction of the constituent elements in an alkali metal halide flux and structurally characterized by single crystal X-ray diffraction techniques. The title compound crystallizes in the rhombohedral space group D{sub 3d}{sup 5}-R{bar 3}m (166, a=7.3552(2) {angstrom}, c=35.832(2) {angstrom}, V=1678.76(13) {angstrom}{sup 3}, Z=12, and R/wR=0.0239/0.0624). The structure is composed of close packed S layers, with a stacking order of ABCBCABABCACAB along the c axis. The Zr and Cu atoms occupy the octahedral and tetrahedral holes between S layers, respectively. Three different kinds of S-M-S layers exist in the structure: layer I has fully occupied Zr and Cu sites, layer II has fully occupied Zr sites but no Cu, and layer III has partially occupied Zr and fully occupied Cu sites. Transport and optical properties indicate that the title compound is a small band gap (1.26 eV) n-type semiconductor.

  19. Effect of high strain rates on peak stress in a Zr-based bulk metallic glass

    SciTech Connect (OSTI)

    Sunny, George; Yuan Fuping; Prakash, Vikas [Department of Mechanical and Aerospace Engineering, Case Western Reserve University, Cleveland, Ohio 44106-7222 (United States); Lewandowski, John [Department of Materials Science and Engineering, Case Western Reserve University, Cleveland, Ohio 44106-7222 (United States)

    2008-11-01T23:59:59.000Z

    The mechanical behavior of Zr{sub 41.25}Ti{sub 13.75}Cu{sub 12.5}Ni{sub 10}Be{sub 22.5} (LM-1) has been extensively characterized under quasistatic loading conditions; however, its mechanical behavior under dynamic loading conditions is currently not well understood. A Split-Hopkinson pressure bar (SHPB) and a single-stage gas gun are employed to characterize the mechanical behavior of LM-1 in the strain-rate regime of 10{sup 2}-10{sup 5}/s. The SHPB experiments are conducted with a tapered insert design to mitigate the effects of stress concentrations and preferential failure at the specimen-insert interface. The higher strain-rate plate-impact compression-and-shear experiments are conducted by impacting a thick tungsten carbide (WC) flyer plate with a sandwich sample comprising a thin bulk metallic glass specimen between two thicker WC target plates. Specimens employed in the SHPB experiments failed in the gage-section at a peak stress of approximately 1.8 GPa. Specimens in the high strain-rate plate-impact experiments exhibited a flow stress in shear of approximately 0.9 GPa, regardless of the shear strain-rate. The flow stress under the plate-impact conditions was converted to an equivalent flow stress under uniaxial compression by assuming a von Mises-like material behavior and accounting for the plane strain conditions. The results of these experiments, when compared to the previous work conducted at quasistatic loading rates, indicate that the peak stress of LM-1 is essentially strain rate independent over the strain-rate range up to 10{sup 5}/s.

  20. Feedback control of HfO{sub 2} etch processing in inductively coupled Cl{sub 2}/N{sub 2}/Ar plasmas

    SciTech Connect (OSTI)

    Lin Chaung; Leou, K.-C.; Li, T.-C.; Lee, L.-S.; Tzeng, P.-J. [Department of Engineering and System Science, National Tsing Hua University, Hsinchu, Taiwan 30043 (China); Electronic Research and Service Organization, Industrial Technology Research Institute, Hsinchu, Taiwan 310 (China)

    2008-09-15T23:59:59.000Z

    The etch rate of HfO{sub 2} etch processing has been feedback controlled in inductively coupled Cl{sub 2}/N{sub 2}/Ar plasmas. The ion current and the root mean square rf voltage on the wafer stage, which are measured using a commercial impedance meter connected to the wafer stage, are chosen as controlled variables because the positive-ion flux and ion energy incident upon the wafer surface are the key factors that determine the etch rate. Two 13.56 MHz rf generators are used to adjust the inductively coupled plasma power and bias power which control ion density and ion energy, respectively. The adopted HfO{sub 2} etch processing used rather low rf voltage. The ion-current value obtained by the power/voltage method is underestimated, so the neural-network model was developed to assist estimating the correct ion-current value. The experimental results show that the etch-rate variation of the closed-loop control is smaller than that of the open-loop control. However, the first wafer effect cannot be eliminated using closed-loop control and thus to achieve a constant etch rate, the chamber-conditioning procedure is required in this etch processing.

  1. Mechanism for atmosphere dependence of laser damage morphology in HfO{sub 2}/SiO{sub 2} high reflective films

    SciTech Connect (OSTI)

    Pu Yunti [Fine Optical Engineering Research Center, Chengdu 610041 (China); Department of Materials Science, Sichuan University, Chengdu 610064 (China); Ma Ping; Chen Songlin; Wang Gang; Pan Feng [Fine Optical Engineering Research Center, Chengdu 610041 (China); Zhu Jiliang; Sun Ping; Zhu Xiaohong; Zhu Jianguo; Xiao Dingquan [Department of Materials Science, Sichuan University, Chengdu 610064 (China)

    2012-07-15T23:59:59.000Z

    We show in this paper single-shot and multi-shot laser-induced damage thresholds (LIDTs) of HfO{sub 2}/SiO{sub 2} high reflective films (the reflectance = 99.9%) are affected by the presence of a water layer absorbed on the surface of the porous films. When the water layer was removed with the process of pumping, the single-shot LIDT measured in vacuum dropped to {approx}48% of that measured in air, while the multi-shot LIDT in vacuum dropped to {approx}47% of its atmospheric value for the high reflective films. Typical damage micrographs of the films in air and in vacuum were obtained, showing distinct damage morphologies. Such atmosphere dependence of the laser damage morphology was found to originate from that formation of a water layer on the surface of porous films could cause an increase of horizontal thermal conductivity and a reduction of vertical thermal conductivity. Moreover, laser-induced periodic ripple damages in air were found in the SiO{sub 2} layer from the micrographs. A model of deformation kinematics was used to illustrate the occurrence of the periodic ripple damage, showing that it could be attributed to a contraction of the HfO{sub 2} layer under irradiation by the 5-ns laser pulses in air.

  2. X-ray photoelectron spectroscopy and ultraviolet photoelectron spectroscopy investigation of Al-related dipole at the HfO{sub 2}/Si interface

    SciTech Connect (OSTI)

    Zhu, L. Q.; Barrett, N.; Jegou, P. [Groupe Photoemission, CEA/IRAMIS/SPCSI, F-91191 Gif-sur-Yvette (France); Martin, F.; Leroux, C.; Martinez, E.; Grampeix, H.; Renault, O.; Chabli, A. [CEA-LETI, MINATEC, 17 rue des Martyrs, 38054 Grenoble Cedex 9 (France)

    2009-01-15T23:59:59.000Z

    The presence of an ultrathin oxide layer at the high-k/SiO{sub 2} interface may result in an interfacial dipole related to the specific high-k dielectric used for the gate stacks. 1 nm HfO{sub 2}/x nmAl{sub 2}O{sub 3}/SiO{sub 2}/Si stacks with different x values (x=0, 0.4, 0.8, 1.2) have been prepared by atomic layer deposition. Using photoelectron spectroscopy, an Al-related interfacial dipole in the HfO{sub 2}/Al{sub 2}O{sub 3}/SiO{sub 2} gate stack has been identified. X-ray photoelectron spectroscopy analysis shows that the dipole is correlated with the formation of an interfacial Al-silicate. The dipole is located at the Al-silicate interface between Al{sub 2}O{sub 3} and SiO{sub 2}, and its strength increases with the increase in Al{sub 2}O{sub 3} thickness because of Al silicate growth. Such Al-related interfacial dipole should have potential applications in future positive metal-oxide-semiconductor devices.

  3. Dispersion of UO{sub 2}F{sub 2} aerosol and HF vapor in the operating floor during winter ventilation at the Paducah Gaseous Diffusion Plant

    SciTech Connect (OSTI)

    Kim, S.H.; Chen, N.C.J.; Taleyarkhan, R.P.; Keith, K.D.; Schmidt, R.W. [Oak Ridge National Lab., TN (United States); Carter, J.C. [J.C. Carter Associates, Inc., Knoxville, TN (United States)

    1996-12-30T23:59:59.000Z

    The gaseous diffusion process is currently employed at two plants in the US: the Paducah Gaseous Diffusion Plant and the Portsmouth Gaseous Diffusion Plant. As part of a facility-wide safety evaluation, a postulated design basis accident involving large line-rupture induced releases of uranium hexafluoride (UF{sub 6}) into the process building of a gaseous diffusion plant (GDP) is evaluated. When UF{sub 6} is released into the atmosphere, it undergoes an exothermic chemical reaction with moisture (H{sub 2}O) in the air to form vaporized hydrogen fluoride (HF) and aerosolized uranyl fluoride (UO{sub 2}F{sub 2}). These reactants disperse in the process building and transport through the building ventilation system. The ventilation system draws outside air into the process building, distributes it evenly throughout the building, and discharges it to the atmosphere at an elevated temperature. Since air is recirculated from the cell floor area to the operating floor, issues concerning in-building worker safety and evacuation need to be addressed. Therefore, the objective of this study is to evaluate the transport of HF vapor and UO{sub 2}F{sub 2} aerosols throughout the operating floor area following B-line break accident in the cell floor area.

  4. Positive bias temperature instability in p-type metal-oxide-semiconductor devices with HfSiON/SiO{sub 2} gate dielectrics

    SciTech Connect (OSTI)

    Samanta, Piyas, E-mail: piyas@vcfw.org [Department of Physics, Vidyasagar College for Women, 39 Sankar Ghosh Lane, Kolkata 700 006 (India); Huang, Heng-Sheng; Chen, Shuang-Yuan [Institute of Mechatronic Engineering, National Taipei University of Technology, No. 1, Sec. 3, Chung-Hsiao E. Rd., Taipei 106, Taiwan (China); Liu, Chuan-Hsi [Department of Mechatronic Technology, National Taiwan Normal University, No. 162, Sec. 1, He-Ping E. Rd., Taipei 106, Taiwan (China); Cheng, Li-Wei [Central R and D Division, United Microelectronics Corporation, No. 3, Li-Hsin Rd. II, Hsinchu 300, Taiwan (China)

    2014-02-21T23:59:59.000Z

    We present a detailed investigation on positive-bias temperature stress (PBTS) induced degradation of nitrided hafnium silicate (HfSiON)/SiO{sub 2} gate stack in n{sup +}-poly crystalline silicon (polySi) gate p-type metal-oxide-semiconductor (pMOS) devices. The measurement results indicate that gate dielectric degradation is a composite effect of electron trapping in as-fabricated as well as newly generated neutral traps, resulting a significant amount of stress-induced leakage current and generation of surface states at the Si/SiO{sub 2} interface. Although, a significant amount of interface states are created during PBTS, the threshold voltage (V{sub T}) instability of the HfSiON based pMOS devices is primarily caused by electron trapping and detrapping. It is also shown that PBTS creates both acceptor- and donor-like interface traps via different depassivation mechanisms of the Si{sub 3}???SiH bonds at the Si/SiO{sub 2} interface in pMOS devices. However, the number of donor-like interface traps ?N{sub it}{sup D} is significantly greater than that of acceptor-like interface traps ?N{sup A}{sub it}, resulting the PBTS induced net interface traps as donor-like.

  5. Influence of deposition pressure and pulsed dc sputtering on pumping properties of Ti-Zr-V nonevaporable getter films

    SciTech Connect (OSTI)

    Malyshev, O. B.; Valizadeh, R.; Colligon, J. S.; Hannah, A.; Middleman, K. J.; Patel, S.; Vishnyakov, V. M. [ASTeC Vacuum Science Group, STFC Daresbury Laboratory, Warrington WA4 4AD (United Kingdom); Department of Chemistry, Manchester Metropolitan University Manchester M1 5GD (United Kingdom); ASTeC Vacuum Science Group, STFC Daresbury Laboratory, Warrington WA4 4AD (United Kingdom); Department of Chemistry, Manchester Metropolitan University, Manchester, M1 5GD (United Kingdom)

    2009-05-15T23:59:59.000Z

    The performance of a UHV vessel can be improved with a new CERN technology nonevaporable getter (NEG) coating, which is already widely used for accelerator vacuum chambers. Better understanding of the processes involved in NEG film deposition, activation, and poisoning should allow optimization and engineering of the film properties, which are necessary for a particular application. Ti-Zr-V NEG films were created by magnetron sputtering from a single Ti-Zr-V target, and the NEG performance and morphology dependence on deposition pressure, sputtering conditions, and substrate surface roughness have been investigated. It was found that the average grain size of the Ti-Zr-V film was 5-6 nm and was broadly independent of the substrate material and deposition conditions. However, film topography and density were shown to depend very much on the substrate surface roughness and deposition conditions. Rough substrates, high working pressures, and the absence of ion bombardment produced open columnar structures, whereas smooth substrates, ion assistance, and low pressures produced much denser layers. X-ray photoelectron spectroscopy studies have shown that full regeneration occurred at 300 degree sign C but film activation started at temperatures of as low as 160 degree sign C. The CO sticking probability reaches its maximum after activation at 250 degree sign C and is found to be up to 0.3 with a pumping capacity in the range of 0.8-1.2 ML. The samples activated at 160 degree sign C have a reduced pumping speed and capacity by an order of magnitude.

  6. Electron-Transport Properties of Amorphous (Zr0.64ni0.36)1-Xalx Alloys

    E-Print Network [OSTI]

    BHATNAGAR, AK; PAN, R.; Naugle, Donald G.

    1989-01-01T23:59:59.000Z

    PHYSICAL REVIEW B VOLUME 39, NUMBER 17 15 JUNE 1989-I Electron transport properties of amorphous (Zro 64Nio 36), ?Al?alloys A. K. Bhatnagar, ' R. Pan, and D. G. Naugle Department ofPhysics, Texas Ad'cM Uniuersity, College Station, Texas 77843...-4242 (Received 28 November 1988; revised manuscript received 16 March 1989) Measurements of the electrical resistivity p(T), thermopower S(T), and Hall coe%cient RH for a series of rapidly quenched Zr-Ni-Al alloys are reported for concentrations from x =0 to 0...

  7. The structural and mechanical properties of a Cu??Zr??(at. %) alloy processed by High-Velocity-Injection (HVI)

    E-Print Network [OSTI]

    Hays, Charles C.

    1986-01-01T23:59:59.000Z

    /vacuum coupled pressure gradient. The molten jet rapidly solidifies, as it is in good thermal contact wi th the cir- cular walls of the copper channel. This process (melting and injection) is carried out in inert protective atmospheres (helium). The samples... produced are in the form of cylindrical rods with large length to diameter ratios (40:1). The samples exhibit a good sur- face finish and are of high density. The structural and mechanical characterization of the Cu6 Zr 0(at. %%u) samples produced...

  8. Negative Thermal Expansion in ZrW{sub 2}O{sub 8}: Mechanisms, Rigid Unit Modes, and Neutron Total Scattering

    SciTech Connect (OSTI)

    Tucker, Matthew G. [Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ (United Kingdom); ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxon OX11 0QX (United Kingdom); Goodwin, Andrew L.; Dove, Martin T. [Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ (United Kingdom); Keen, David A. [Physics Department, Oxford University, Clarendon Laboratory, Parks Road, Oxford OX1 3PU (United Kingdom); ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxon OX11 0QX (United Kingdom); Wells, Stephen A. [Biological Physics, Bateman Physical Sciences Building, Arizona State University, Tempe, Arizona 85287-1504 (United States); Evans, John S.O. [Department of Chemistry, University Science Laboratories, South Road, Durham DH1 3LE (United Kingdom)

    2005-12-16T23:59:59.000Z

    The local structure of the low-temperature ordered phase of the negative thermal expansion (NTE) material ZrW{sub 2}O{sub 8} has been investigated by reverse Monte Carlo (RMC) modeling of neutron total scattering data. We obtain, for the first time, quantitative measurements of the extent to which the WO{sub 4} and ZrO{sub 6} polyhedra move as rigid units, and we show that these values are consistent with the predictions of rigid unit mode theory. We suggest that rigid unit modes are associated with the NTE. Our results do not support a recent interpretation of x-ray-absorption fine structure spectroscopy data in terms of a larger rigid structural component involving the Zr-O-W linkage.

  9. COMPUTATIONAL MODELING, SYNTHESIS, AND CHARACTERIZATION OF BaZr1-xYxO3-8 SOLID STATE PROTON CONDUCTOR

    SciTech Connect (OSTI)

    Boris Merinov; Claudio O. Dorso; William A. Goddard III; Jian Wu; Sossina Haile

    2003-10-30T23:59:59.000Z

    During the second semiannual period we have carried out a series of QM calculations on the BaZr{sub 1-x}Y{sub x}H{sub x}O{sub 3} proton conductor to determine the equilibrium proton positions and corresponding energies. We find that the size of the crystal cell is very important for the identification of the equilibrium proton positions. To derive ReaxFF parameters for Pt-surfaces and for H-transfer in Y-doped BaZrO{sub 3}, we carried out QM-calculations on the structures and energies of relevant condensed phases and cluster systems. These data then served as a training set to optimize the ReaxFF parameters. ReaxFF for various bulk metals (Pt, Zr, and Y) and metal clusters (Pt) was developed. BaZr{sub 1-x}Y{sub x}O{sub 3-{delta}} with x = 0.2, 0.3, 0.4, 0.5 was synthesized using a modified Pechini method and characterization (X-ray diffraction, scanning electron microscopy, and impedance spectroscopy) of this material was performed. We find that a single perovskite phase is formed in BaZr{sub 1-x}Y{sub x}O{sub 3-{delta}}. The proton conductivity of BaZr{sub 1-x}Y{sub x}O{sub 3-{delta}} with x = 0.5 is significantly lower than the conductivity of the samples with Y-dopant concentrations of 0.1 and 0.2.

  10. Characterization of self-propagating formation reactions in Ni/Zr multilayered foils using reaction heats, velocities, and temperature-time profiles

    SciTech Connect (OSTI)

    Barron, S. C.; Knepper, R.; Walker, N.; Weihs, T. P.

    2011-01-11T23:59:59.000Z

    We report on intermetallic formation reactions in vapor-deposited multilayered foils of Ni/Zr with 70 nm bilayers and overall atomic ratios of Ni:Zr, 2 Ni:Zr, and 7 Ni:2 Zr. The sequence of alloy phase formation and the stored energy is evaluated at slow heating rates (~1 K/s) using differential scanning calorimetry (DSC) traces to 725ºC. All three chemistries initially form a Ni-Zr amorphous phase which crystallizes first to the intermetallic NiZr. The heat of reaction to the final phase is 34-36 kJ/mol atom for all chemistries. Intermetallic formation reactions are also studied at rapid heating rates (greater than 105 K/s) in high temperature, self-propagating reactions which can be ignited in these foils by an electric spark. We find that reaction velocities and maximum reaction temperatures (Tmax) are largely independent of foil chemistry at 0.6 ± 0.1 m/s and 1220 ± 50 K, respectively, and that the measured Tmax is more than 200 K lower than predicted adiabatic temperatures (Tad). The difference between Tmax and Tad is explained by the prediction that transformation to the final intermetallic phases occurs after Tmax and results in the release of 20-30 % of the total heat of reaction and a delay in rapid cooling.

  11. Effects of additive C{sub 4}F{sub 8} during inductively coupled BCl{sub 3}/C{sub 4}F{sub 8}/Ar plasma etching of TaN and HfO{sub 2} for gate stack patterning

    SciTech Connect (OSTI)

    Ko, J. H.; Kim, D. Y.; Park, M. S.; Lee, N.-E.; Lee, S. S.; Ahn, Jinho; Mok, Hyungsoo [School of Advanced Materials Science and Engineering, and Center for Advanced Plasma Surface Technology, Sungkyunkwan University, Suwon, Kyunggi-do 440-746 (Korea, Republic of); Division of Advanced Materials Science and Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of); Department of Electrical Engineering, Konkuk University, 1 Hwayangdong, Gwangjingu, Seoul 143-701 (Korea, Republic of)

    2007-07-15T23:59:59.000Z

    In this work, the authors investigated the etching characteristics of TaN and HfO{sub 2} layers for gate stack patterning in BCl{sub 3}/Ar and BCl{sub 3}/C{sub 4}F{sub 8}/Ar inductively coupled plasmas and the effects of C{sub 4}F{sub 8} addition on the etch selectivity of the TaN to the HfO{sub 2} layer. Addition of C{sub 4}F{sub 8} gas to the BCl{sub 3}/Ar chemistry improved the TaN/HfO{sub 2} etch selectivity because adding the C{sub 4}F{sub 8} gas enhances the formation of the CF{sub x}Cl{sub y} passivation layer on HfO{sub 2} surface and decreased the HfO{sub 2} etch rate more rapidly than the TaN etch rate in a disproportionate way. Reduction in the etch time for HfO{sub 2} layer also increases the TaN/HfO{sub 2} etch selectivity because the etch time gets closer to the initiation time for HfO{sub 2} etching.

  12. Selective etching of high-k HfO{sub 2} films over Si in hydrogen-added fluorocarbon (CF{sub 4}/Ar/H{sub 2} and C{sub 4}F{sub 8}/Ar/H{sub 2}) plasmas

    SciTech Connect (OSTI)

    Takahashi, Kazuo; Ono, Kouichi [Department of Aeronautics and Astronautics, Kyoto University, Yoshida-Honmachi, Sakyo-ku, Kyoto 606-8501 (Japan)

    2006-05-15T23:59:59.000Z

    Inductively coupled hydrogen-added fluorocarbon (CF{sub 4}/Ar/H{sub 2} and C{sub 4}F{sub 8}/Ar/H{sub 2}) plasmas were used to etch HfO{sub 2}, which is a promising high-dielectric-constant material for the gate of complementary metal-oxide-semiconductor devices. The etch rates of HfO{sub 2} and Si were drastically changed depending on the additive-H{sub 2} flow rate in C{sub 4}F{sub 8}/Ar/H{sub 2} plasmas. The highly selective etching of HfO{sub 2} over Si was done in the condition with an additive-H{sub 2} flow rate, where the Si surface was covered with the fluorocarbon polymer. The results of x-ray photoelectron spectroscopy indicated that the carbon content of the selectively etched HfO{sub 2} surface was extremely low compared with the preetched surface contaminated by adventitious hydrocarbon in atmosphere. In the gas phase of the C{sub 4}F{sub 8}/Ar/H{sub 2} plasmas, Hf hydrocarbide molecules such as metal-organic compounds and Hf hydrofluoride were detected by a quadrupole mass analyzer. These findings indicate that the fluorine species, carbon, and hydrogen can work to etch HfO{sub 2} and that the carbon species also plays an important role in selective etching of HfO{sub 2} over Si.

  13. Usefulness of gel-casting method in the fabrication of nonstoichiometric CaZrO{sub 3}-based electrolytes for high temperature application

    SciTech Connect (OSTI)

    Dudek, Magdalena [AGH - University of Science and Technology, Faculty of Energy and Fuels, 30-059 Cracow (Poland)

    2009-09-15T23:59:59.000Z

    Hydrogels obtained from lower toxicity monomers of N-(hydroxymethyl)acrylamide and N,N'-methylenebisacrylamide were applied to form nonstoichiometric CaZrO{sub 3}-based electrolytes. A coprecipitation-calcination method with ((NH{sub 4}){sub 2}C{sub 2}O{sub 4}) in concentrated NH{sub 3} aqueous solution was used to synthesise CaZrO{sub 3} involving 51 mol.% CaO (CZ-51) powder. The gas-tight CaZrO{sub 3}-based rods were prepared by the gel-casting method with 45 vol.% suspension and then sintered at 1500 deg. C-2 h. It was found that in low oxygen partial pressure, the nonstoichiometric CaZrO{sub 3} obtained by gel-casting method were pure oxide ion conductors. These samples exhibited comparable electrical conductivity values to isostatically compressed pellets starting from the same powder. The results of experiments on thermochemical stability of CZ-51 gel-cast shapes at high temperatures in air or gas mixtures involving 2-50 vol.% H{sub 2}, as well as the corrosion resistance in exhaust gases from a self-ignition engine were also presented and discussed. The thermal resistance of CaZrO{sub 3} obtained rods against molten nickel or iron was also examined. Based upon these investigations, it is evident that only in hydrogen-rich gas atmospheres can the stability of CaZrO{sub 3} shapes be limited due to the presence of CaO precipitation as a second phase. The nonstoichiometric CaZrO{sub 3} (CZ-51) gel-cast materials were also tested in solid galvanic cells, designed to study thermodynamic properties of oxide materials, important for SOFC and energy technology devices. In this way, the Gibbs energy of NiM{sub 2}O{sub 4}, M = Cr, Fe, at 650-1000 deg. C was determined. The CaZrO{sub 3} involving 51 mol.% CaO gel-cast sintered shapes seems to be promising solid electrolytes for electrochemical oxygen probes in control of metal processing and thermodynamic studies of materials important for the development of the energy industry.

  14. Collapse of ferromagnetism in itinerant-electron system: A magnetic, transport properties, and high pressure study of (Hf,Ta)Fe{sub 2} compounds

    SciTech Connect (OSTI)

    Diop, L. V. B., E-mail: leopold.diop@neel.cnrs.fr; Isnard, O. [Univ. Grenoble Alpes, Inst NEEL, F-38042 Grenoble (France); CNRS, Inst NEEL, F-38042 Grenoble (France); Kastil, J. [Univ. Grenoble Alpes, Inst NEEL, F-38042 Grenoble (France); CNRS, Inst NEEL, F-38042 Grenoble (France); Institute of Physics AS CR v.v.i., Na Slovance 2, 182 21 Prague 8 (Czech Republic); Arnold, Z.; Kamarad, J. [Institute of Physics AS CR v.v.i., Na Slovance 2, 182 21 Prague 8 (Czech Republic)

    2014-10-28T23:59:59.000Z

    The magnetism and transport properties were studied for Laves (Hf,Ta)Fe{sub 2} itinerant-electron compounds, which exhibit a temperature-induced first-order transition from the ferromagnetic (FM) to the antiferromagnetic (AFM) state upon heating. At finite temperatures, the field-induced metamagnetic phase transition between the AFM and FM has considerable effects on the transport properties of these model metamagnetic compounds. A large negative magnetoresistance of about 14% is observed in accordance with the metamagnetic transition. The magnetic phase diagram is determined for the Laves Hf{sub 1?x}Ta{sub x}Fe{sub 2} series and its Ta concentration dependence discussed. An unusual behavior is revealed in the paramagnetic state of intermediate compositions, it gives rise to the rapid increase and saturation of the local spin fluctuations of the 3d electrons. This new result is analysed in the frame of the theory of Moriya. For a chosen composition Hf{sub 0.825}Ta{sub 0.175}Fe{sub 2}, exhibiting such remarkable features, a detailed investigation is carried out under hydrostatic pressure up to 1?GPa in order to investigate the volume effect on the magnetic properties. With increasing pressure, the magnetic transition temperature T{sub FM-AFM} from ferromagnetic to antiferromagnetic order decreases strongly non-linearly and disappears at a critical pressure of 0.75?GPa. In the pressure-induced AFM state, the field-induced first-order AFM-FM transition appears and the complex temperature dependence of the AFM-FM transition field is explained by the contribution from both the magnetic and elastic energies caused by the significant temperature variation of the amplitude of the local Fe magnetic moment. The application of an external pressure leads also to the progressive decrease of the Néel temperature T{sub N}. In addition, a large pressure effect on the spontaneous magnetization M{sub S} for pressures below 0.45?GPa, dln(M{sub s})/dP?=??6.3?×?10{sup ?2?}GPa{sup ?1} was discovered. The presented results are consistent with Moriya's theoretical predictions and can significantly help to better understand the underlying physics of itinerant electron magnetic systems nowadays widely investigated for both fundamental and applications purposes.

  15. TUNGSTEN ISOTOPIC COMPOSITIONS IN STARDUST SiC GRAINS FROM THE MURCHISON METEORITE: CONSTRAINTS ON THE s-PROCESS IN THE Hf-Ta-W-Re-Os REGION

    SciTech Connect (OSTI)

    Avila, Janaina N.; Ireland, Trevor R.; Holden, Peter [Research School of Earth Sciences, Australian National University, Canberra, ACT 0200 (Australia); Lugaro, Maria; Buntain, Joelene [Centre for Stellar and Planetary Astrophysics, Monash University, Clayton, VIC 3800 (Australia); Gyngard, Frank; Zinner, Ernst; Amari, Sachiko [Laboratory for Space Sciences and the Department of Physics, Washington University, One Brookings Drive, St. Louis, MO 63130 (United States); Cristallo, Sergio [Departamento de Fisica Teorica y del Cosmos, Universidad de Granada, Granada 18071 (Spain); Karakas, Amanda, E-mail: janaina.avila@anu.edu.au [Mount Stromlo Observatory, Australian National University, Weston Creek, ACT 2611 (Australia)

    2012-01-01T23:59:59.000Z

    We report the first tungsten isotopic measurements in stardust silicon carbide (SiC) grains recovered from the Murchison carbonaceous chondrite. The isotopes {sup 182,183,184,186}W and {sup 179,180}Hf were measured on both an aggregate (KJB fraction) and single stardust SiC grains (LS+LU fraction) believed to have condensed in the outflows of low-mass carbon-rich asymptotic giant branch (AGB) stars with close-to-solar metallicity. The SiC aggregate shows small deviations from terrestrial (= solar) composition in the {sup 182}W/{sup 184}W and {sup 183}W/{sup 184}W ratios, with deficits in {sup 182}W and {sup 183}W with respect to {sup 184}W. The {sup 186}W/{sup 184}W ratio, however, shows no apparent deviation from the solar value. Tungsten isotopic measurements in single mainstream stardust SiC grains revealed lower than solar {sup 182}W/{sup 184}W, {sup 183}W/{sup 184}W, and {sup 186}W/{sup 184}W ratios. We have compared the SiC data with theoretical predictions of the evolution of W isotopic ratios in the envelopes of AGB stars. These ratios are affected by the slow neutron-capture process and match the SiC data regarding their {sup 182}W/{sup 184}W, {sup 183}W/{sup 184}W, and {sup 179}Hf/{sup 180}Hf isotopic compositions, although a small adjustment in the s-process production of {sup 183}W is needed in order to have a better agreement between the SiC data and model predictions. The models cannot explain the {sup 186}W/{sup 184}W ratios observed in the SiC grains, even when the current {sup 185}W neutron-capture cross section is increased by a factor of two. Further study is required to better assess how model uncertainties (e.g., the formation of the {sup 13}C neutron source, the mass-loss law, the modeling of the third dredge-up, and the efficiency of the {sup 22}Ne neutron source) may affect current s-process predictions.

  16. Fission gas bubble nucleated cavitational swelling of the alpha-uranium phase of irradiated U-Pu-Zr fuel

    SciTech Connect (OSTI)

    Rest, J.

    1992-04-01T23:59:59.000Z

    Cavitational swelling has been identified as a potential swelling mechanism for the alpha uranium phase of irradiated U-Pu-Zr metal fuels for the Integral Fast Reactor being developed at Argonne National Laboratory. The trends of U-Pu-Zr swelling data prior to fuel cladding contact can be interpreted in terms of unrestrained cavitational driven swelling. It is theorized that the swelling mechanisms at work in the alpha uranium phase can be modeled by single vacancy and single interstitial kinetics with intergranular gas bubbles providing the void nuclei, avoiding the use of complicated defect interaction terms required for the calculation of void nucleation. The focus of the kinetics of fission gas evolution as it relates to cavitational swelling is prior to the formation of a significant amount of interconnected porosity and is on the development of small intergranular gas bubbles which can act as void nuclei. Calculations for the evolution of intergranular fission gas bubbles show that they provide critical cavity sizes (i.e., the size above which the cavity will grow by bias-driven vacancy flux) consistent with the observed incubation dose for the onset of rapid swelling and gas release.

  17. Experimental study of the low-lying structure of {sup 94}Zr with the (n,n{sup '}{gamma}) reaction

    SciTech Connect (OSTI)

    Elhami, E.; Orce, J. N.; Scheck, M.; Mukhopadhyay, S.; Choudry, S. N.; McEllistrem, M. T. [Department of Physics and Astronomy, University of Kentucky, Lexington, Kentucky 40506-0055 (United States); Yates, S. W. [Department of Physics and Astronomy, University of Kentucky, Lexington, Kentucky 40506-0055 (United States); Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506-0055 (United States); Angell, C.; Boswell, M.; Karwowski, H. J. [Department of Physics and Astronomy, University of North Carolina, Chapel Hill, North Carolina 27599-3255 (United States); Triangle Universities Nuclear Laboratory (TUNL), Durham, North Carolina 27708 (United States); Fallin, B.; Howell, C. R.; Hutcheson, A.; Parpottas, Y.; Tonchev, A. P.; Tornow, W. [Triangle Universities Nuclear Laboratory (TUNL), Durham, North Carolina 27708 (United States); Department of Physics, Duke University, Durham, North Carolina 27708-0308 (United States); Kelley, J. H. [Triangle Universities Nuclear Laboratory (TUNL), Durham, North Carolina 27708 (United States); Department of Physics, North Carolina State University, Raleigh, North Carolina 27695-8202 (United States)

    2008-12-15T23:59:59.000Z

    The low-lying structure of {sub 40}{sup 94}Zr was studied with the (n,n{sup '}{gamma}) reaction, and a level scheme was established based on excitation function and {gamma}{gamma} coincidence measurements. Branching ratios, multipole mixing ratios, and spin assignments were determined from angular distribution measurements. Lifetimes of levels up to 3.4 MeV were measured by the Doppler-shift attenuation method, and for many transitions the reduced transition probabilities were determined. In addition to the anomalous 2{sub 2}{sup +} state, which has a larger B(E2;2{sub 2}{sup +}{yields}0{sub 1}{sup +}) value than the B(E2;2{sub 1}{sup +}{yields}0{sub 1}{sup +}), the experimental results revealed interesting and unusual properties of the low-lying states in {sup 94}Zr. In a simple interpretation, the excited states are classified in two distinct categories, i.e., those populating the 2{sub 2}{sup +} state and those decaying to the 2{sub 1}{sup +} state.

  18. High temperature oxidation behavior of austenitic stainless steel AISI 304 in steam of nanofluids contain nanoparticle ZrO2

    SciTech Connect (OSTI)

    Prajitno, Djoko Hadi, E-mail: djokohp@batan.go.id; Syarif, Dani Gustaman, E-mail: djokohp@batan.go.id [Research Center for Nuclear Materials and Radiometry, Jl. Tamansari 71, Bandung 40132 (Indonesia)

    2014-03-24T23:59:59.000Z

    The objective of this study is to evaluate high temperature oxidation behavior of austenitic stainless steel SS 304 in steam of nanofluids contain nanoparticle ZrO{sub 2}. The oxidation was performed at high temperatures ranging from 600 to 800°C. The oxidation time was 60 minutes. After oxidation the surface of the samples was analyzed by different methods including, optical microscope, scanning electron microscope (SEM) and X-ray diffraction (XRD). X-ray diffraction examination show that the oxide scale formed during oxidation of stainless steel AISI 304 alloys is dominated by iron oxide, Fe{sub 2}O{sub 3}. Minor element such as Cr{sub 2}O{sub 3} is also appeared in the diffraction pattern. Characterization by optical microscope showed that cross section microstructure of stainless steel changed after oxidized with the oxide scale on the surface stainless steels. SEM and x-ray diffraction examination show that the oxide of ZrO{sub 2} appeared on the surface of stainless steel. Kinetic rate of oxidation of austenite stainless steel AISI 304 showed that increasing oxidation temperature and time will increase oxidation rate.

  19. Comparison of the vacuum-ultraviolet radiation response of HfO{sub 2}/SiO{sub 2}/Si dielectric stacks with SiO{sub 2}/Si

    SciTech Connect (OSTI)

    Upadhyaya, G. S.; Shohet, J. L. [Plasma Processing and Technology Laboratory, and Department of Electrical and Computer Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States)

    2007-02-12T23:59:59.000Z

    Vacuum ultraviolet (vuv) emitted during plasma processing degrades dielectrics by generating electron-hole pairs. VUV-induced charging of SiO{sub 2}/p-Si and HfO{sub 2}/SiO{sub 2}/p-Si dielectric stacks are compared. For SiO{sub 2}/p-Si, charging is observed for photon energies >15 eV by ionization of dielectric atoms from photoinjected electrons. In HfO{sub 2}/SiO{sub 2}/p-Si, charging is observed for photon >10 eV and is due to ionization by photoinjected electrons and by H{sup +} trapping in the HfO{sub 2}/SiO{sub 2} bulk. Hydrogen appears during annealing at the Si-SiO{sub 2} interface forming Si-H, which, during irradiation, is depassivated by photoinjected electrons. The authors conclude that dielectric charging in thin oxides (<10 nm) occurs more easily in HfO{sub 2}/SiO{sub 2} than in SiO{sub 2}.

  20. In-operando hard X-ray photoelectron spectroscopy study on the impact of current compliance and switching cycles on oxygen and carbon defects in resistive switching Ti/HfO{sub 2}/TiN cells

    SciTech Connect (OSTI)

    Sowinska, Malgorzata, E-mail: sowinska@ihp-microelectronics.com; Bertaud, Thomas; Walczyk, Damian; Calka, Pauline; Walczyk, Christian [IHP, Im Technologiepark 25, 15236 Frankfurt (Oder) (Germany); Thiess, Sebastian [Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, 22607 Hamburg (Germany); Alff, Lambert [Institute of Materials Science, Technische Universität Darmstadt, 64287 Darmstadt (Germany); Schroeder, Thomas [IHP, Im Technologiepark 25, 15236 Frankfurt (Oder) (Germany); Brandenburgische Technische Universität, Konrad-Zuse-Strasse 1, 03046 Cottbus (Germany)

    2014-05-28T23:59:59.000Z

    In this study, direct experimental materials science evidence of the important theoretical prediction for resistive random access memory (RRAM) technologies that a critical amount of oxygen vacancies is needed to establish stable resistive switching in metal-oxide-metal samples is presented. In detail, a novel in-operando hard X-ray photoelectron spectroscopy technique is applied to non-destructively investigates the influence of the current compliance and direct current voltage sweep cycles on the Ti/HfO{sub 2} interface chemistry and physics of resistive switching Ti/HfO{sub 2}/TiN cells. These studies indeed confirm that current compliance is a critical parameter to control the amount of oxygen vacancies in the conducting filaments in the oxide layer during the RRAM cell operation to achieve stable switching. Furthermore, clear carbon segregation towards the Ti/HfO{sub 2} interface under electrical stress is visible. Since carbon impurities impact the oxygen vacancy defect population under resistive switching, this dynamic carbon segregation to the Ti/HfO{sub 2} interface is suspected to negatively influence RRAM device endurance. Therefore, these results indicate that the RRAM materials engineering needs to include all impurities in the dielectric layer in order to achieve reliable device performance.

  1. Effects of N{sub 2} remote plasma nitridation on the structural and electrical characteristics of the HfO{sub 2} gate dielectrics grown using remote plasma atomic layer deposition methods

    SciTech Connect (OSTI)

    Choi, Jihoon; Kim, Seokhoon; Kim, Jinwoo; Kang, Hyunseok; Jeon, Hyeongtag; Bae, Choelhwyi [Division of Materials Science and Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of); Department of Physics, North Carolina State University, Raleigh, North Carolina 27695 (United States)

    2006-07-15T23:59:59.000Z

    The characteristics of remote plasma atomic layer deposited HfO{sub 2} on Si, which has a very thin SiO{sub 2} interlayer with and without remote plasma nitridation (RPN), have been investigated. Small amounts of N atoms were successfully incorporated by RPN pretreatment, in which the dominant emission species were excited atomic nitrogen (N{sup *}) and excited molecular nitrogen (N{sub 2}{sup *}), into a very thin SiO{sub 2} interlayer for the growth of HfO{sub 2} thin film. The thin ({approx}1.5 nm) intermediate layer containing nitrogen, which was prepared by sequential O{sub 2} and N{sub 2} remote plasma treatment of the Si substrate, can effectively suppress growth of the unintentional interface layer. In addition, it enhances the thermal stability and the resistance to oxygen diffusion during rapid thermal annealing. The HfO{sub 2} film containing the remote plasma nitrided SiO{sub 2} interlayer annealed at 800 deg. C showed a lower equivalent oxide thickness of {approx}1.89 nm and a lower leakage current density (3.78x10{sup -7} A cm{sup -2} at |V{sub G}-V{sub FB}|=2 V) compared to a non-nitrided sample of the same physical thickness. Also, we compared the characteristics of HfO{sub 2} films annealed in two different ambient environments, N{sub 2} and O{sub 2}.

  2. Analysis of trap state densities at HfO{sub 2}/In{sub 0.53}Ga{sub 0.47}As interfaces

    SciTech Connect (OSTI)

    Hwang, Yoontae; Engel-Herbert, Roman; Rudawski, Nicholas G.; Stemmer, Susanne [Materials Department, University of California, Santa Barbara, California 93106-5050 (United States)

    2010-03-08T23:59:59.000Z

    HfO{sub 2} was deposited on n- and p-type In{sub 0.53}Ga{sub 0.47}As by chemical beam deposition. Interface trap densities (D{sub it}) and their energy level distribution were quantified using the conductance method in a wide temperature range (77 to 300 K). A trap level close to the intrinsic energy level caused the D{sub it} to rise above 10{sup 13} cm{sup -2} eV{sup -1}. The trap level at midgap gives rise to false inversion behavior in the capacitance-voltage curves for n-type channels at room temperature. The apparent decrease of the D{sub it} close to the band edges is discussed.

  3. Film properties of low temperature HfO{sub 2} grown with H{sub 2}O, O{sub 3}, or remote O{sub 2}-plasma

    SciTech Connect (OSTI)

    Richter, Claudia, E-mail: Claudia.Richter@namlab.com; Schenk, Tony; Schroeder, Uwe [NaMLab gGmbH, Noethnitzerstr. 64, 01187 Dresden (Germany); Mikolajick, Thomas [NaMLab gGmbH, Noethnitzerstr. 64, 01187 Dresden, Germany and Institut für Halbleiter und Mikrosystemtechnik, TU Dresden, Noethnitzerstr. 64, 01187 Dresden (Germany)

    2014-01-15T23:59:59.000Z

    A reduction of the deposition temperature is necessary for atomic layer deposition (ALD) on organic devices. HfO{sub 2} films were deposited by ALD on silicon substrates in a wide temperature range from 80 to 300?°C with tetrakis[ethylmethylamino]hafnium as metal precursor and H{sub 2}O, O{sub 3}, or an remote O{sub 2}-plasma as oxygen source. Growth rate and density were correlated to electrical properties like dielectric constant and leakage current of simple capacitor structures to evaluate the impact of different process conditions. Process optimizations were performed to reduce film imperfections visible at lower deposition temperatures. Additionally, the influence of postdeposition annealing on the structural and electrical properties was studied.

  4. Reduction of native oxides on InAs by atomic layer deposited Al{sub 2}O{sub 3} and HfO{sub 2}

    SciTech Connect (OSTI)

    Timm, R.; Fian, A.; Hjort, M.; Thelander, C.; Lind, E.; Andersen, J. N.; Wernersson, L.-E.; Mikkelsen, A. [Department of Physics, Nanometer Structure Consortium, Lund University, P.O. Box 118, 22 100 Lund (Sweden)

    2010-09-27T23:59:59.000Z

    Thin high-{kappa} oxide films on InAs, formed by atomic layer deposition, are the key to achieve high-speed metal-oxide-semiconductor devices. We have studied the native oxide and the interface between InAs and 2 nm thick Al{sub 2}O{sub 3} or HfO{sub 2} layers using synchrotron x-ray photoemission spectroscopy. Both films lead to a strong oxide reduction, obtaining less than 10% of the native As-oxides and between 10% and 50% of the native In-oxides, depending on the deposition temperature. The ratio of native In- to As-oxides is determined to be 2:1. The exact composition and the influence of different oxidation states and suboxides is discussed in detail.

  5. Surface and interfacial reaction study of half cycle atomic layer deposited HfO{sub 2} on chemically treated GaSb surfaces

    SciTech Connect (OSTI)

    Zhernokletov, D. M. [Department of Physics, University of Texas at Dallas, Richardson, Texas 75080 (United States)] [Department of Physics, University of Texas at Dallas, Richardson, Texas 75080 (United States); Dong, H.; Brennan, B.; Kim, J. [Department of Materials Science and Engineering, University of Texas at Dallas, Richardson, Texas 75080 (United States)] [Department of Materials Science and Engineering, University of Texas at Dallas, Richardson, Texas 75080 (United States); Yakimov, M.; Tokranov, V.; Oktyabrsky, S. [College of Nanoscale Science and Engineering, University at Albany - SUNY, Albany, New York 12203 (United States)] [College of Nanoscale Science and Engineering, University at Albany - SUNY, Albany, New York 12203 (United States); Wallace, R. M. [Department of Physics, University of Texas at Dallas, Richardson, Texas 75080 (United States) [Department of Physics, University of Texas at Dallas, Richardson, Texas 75080 (United States); Department of Materials Science and Engineering, University of Texas at Dallas, Richardson, Texas 75080 (United States)

    2013-04-01T23:59:59.000Z

    An in situ half-cycle atomic layer deposition/X-ray photoelectron spectroscopy (XPS) study was conducted in order to investigate the evolution of the HfO{sub 2} dielectric interface with GaSb(100) surfaces after sulfur passivation and HCl etching, designed to remove the native oxides. With the first pulses of tetrakis(dimethylamido)hafnium(IV) and water, a decrease in the concentration of antimony oxide states present on the HCl-etched surface is observed, while antimony sulfur states diminished below the XPS detection limit on sulfur passivated surface. An increase in the amount of gallium oxide/sulfide is seen, suggesting oxygen or sulfur transfers from antimony to gallium during antimony oxides/sulfides decomposition.

  6. Laser damage study of nodules in electron-beam-evaporated HfO{sub 2}/SiO{sub 2} high reflectors

    SciTech Connect (OSTI)

    Cheng Xinbin; Shen Zhengxiang; Jiao Hongfei; Zhang Jinlong; Ma Bin; Ding Tao; Lu Jiangtao; Wang Xiaodong; Wang Zhanshan

    2011-03-20T23:59:59.000Z

    A reactive electron beam evaporation process was used to fabricate 1.064 {mu}mHfO{sub 2}/SiO{sub 2} high reflectors. The deposition process was optimized to reduce the nodular density. Cross-sectioning of nodular defects by a focused ion-beam milling instrument showed that the nodule seeds were the residual particles on the substrate and the particulates from the silica source ''splitting.'' After optimizing the substrate preparation procedure and the evaporation process, a low nodular density of 2.7/mm{sup 2} was achieved. The laser damage test revealed that the ejection fluences and damage growth behaviors of nodules created from deep or shallow seeds were totally different. A mechanism based on directional plasma scald was proposed to interpret observed damage growth phenomenon.

  7. COMPARISON OF THE CORROSION BEHAVIOR OF A BULK AMORPHOUS METAL, Zr41.2Ti13.8Cu12.5Ni10Be22.5,

    E-Print Network [OSTI]

    Ritchie, Robert

    COMPARISON OF THE CORROSION BEHAVIOR OF A BULK AMORPHOUS METAL, Zr41.2Ti13.8Cu12.5Ni10Be22 exhibit excellent corrosion resistance (4­7), which has been explained in terms of their structural researchers attribute "good corrosion resistance" to the entire class of amorphous metals. It is this point

  8. From fluorite to pyrochlore: Characterisation of local and average structure of neodymium zirconate, Nd{sub 2}Zr{sub 2}O{sub 7}

    SciTech Connect (OSTI)

    Payne, Julia L. [Department of Chemistry, Durham University, South Road, Durham DH1 3LE (United Kingdom); Tucker, Matthew G. [ISIS Facility, Rutherford Appleton Laboratory, Didcot, Oxfordshire OX11 0QX (United Kingdom); Evans, Ivana Radosavljevi?, E-mail: ivana.radosavljevic@durham.ac.uk [Department of Chemistry, Durham University, South Road, Durham DH1 3LE (United Kingdom)

    2013-09-15T23:59:59.000Z

    The structural characterisation of Nd{sub 2}Zr{sub 2}O{sub 7} prepared via a precursor route was performed using a combination of local and average structure probes (neutron total scattering, X-ray and neutron diffraction). We present the first total scattering and reverse Monte Carlo (RMC) modelling study of Nd{sub 2}Zr{sub 2}O{sub 7}, which provides compelling evidence for the adoption of a disordered fluorite-type structure by Nd{sub 2}Zr{sub 2}O{sub 7} prepared by a low-temperature precursor route. Annealing the material at high temperatures leads to a transformation to a pyrochlore-type structure; however, Rietveld refinement using powder neutron diffraction data shows that the oxygen sublattice retains a degree of disorder. - Graphical abstract: Display Omitted - Highlights: • The first total scattering and RMC modelling study of Nd{sub 2}Zr{sub 2}O{sub 7}. • Demonstration that the synthetic route influences the crystal structure adopted. • Insight into the importance of total scattering in studies of complex superstructures, especially for nano-sized materials.

  9. Growth and Properties of (001)-oriented Pb(Zr?.??Ti?.??)O?/LaNiO? Films on Si(001) Substrates with TiN Buffer Layers

    E-Print Network [OSTI]

    Zhu, Tie-Jun

    Pulsed laser deposition has been used to grow Pb(Zr?.??Ti?.??)O? (PZT)/LaNiO? (LNO) heterostructures with restricted crystallographic orientations on bare Si(001) and SiO?-coated Si(001) substrates, using TiN buffer layers. ...

  10. A thermokinetic model describing the vaporization behavior of U{sub x}Zr{sub 1-x}C{sub 1-y} in hydrogen

    SciTech Connect (OSTI)

    Butt, D.P

    1993-05-01T23:59:59.000Z

    This paper describes the thermodynamics and kinetics of the corrosion of U{sub x}Zr{sub 1-x}C{sub 1-y} in hydrogen gas. It describes how corrosion rates are influenced by variables such as pressure, temperature, and gas flow rate. A model is developed which agrees with experimental steady-state corrosion rates at 1 atm between 2670 and 3100 K. It is shown that under steady-state conditions the corrosion flux is rate limited by the vapor phase transport of Zr(g) away from the solid surface to the bulk gas stream where the partial pressure of Zr(g) is determined by the congruently vaporizing surface composition. Extrapolation of the model to higher pressures indicates that Zr(g) transport should also be rate limiting at higher pressures but the corrosion rate should decrease slightly with increased hydrogen pressure due to reduced gaseous diffusion rates. The model predicts that the corrosion rate will increase as the square root of gas velocity for a given temperature and pressure. Calculations demonstrating the effects of gas velocity are in agreement with experimental studies.

  11. A thermokinetic model describing the vaporization behavior of U[sub x]Zr[sub 1-x]C[sub 1-y] in hydrogen

    SciTech Connect (OSTI)

    Butt, D.P.

    1993-01-01T23:59:59.000Z

    This paper describes the thermodynamics and kinetics of the corrosion of U[sub x]Zr[sub 1-x]C[sub 1-y] in hydrogen gas. It describes how corrosion rates are influenced by variables such as pressure, temperature, and gas flow rate. A model is developed which agrees with experimental steady-state corrosion rates at 1 atm between 2670 and 3100 K. It is shown that under steady-state conditions the corrosion flux is rate limited by the vapor phase transport of Zr(g) away from the solid surface to the bulk gas stream where the partial pressure of Zr(g) is determined by the congruently vaporizing surface composition. Extrapolation of the model to higher pressures indicates that Zr(g) transport should also be rate limiting at higher pressures but the corrosion rate should decrease slightly with increased hydrogen pressure due to reduced gaseous diffusion rates. The model predicts that the corrosion rate will increase as the square root of gas velocity for a given temperature and pressure. Calculations demonstrating the effects of gas velocity are in agreement with experimental studies.

  12. Giant dielectric response in Pb,,Zr,Ti...O3Pb2Ru2O6.5 all-ceramic percolative composite

    E-Print Network [OSTI]

    Bobnar, Vid

    Giant dielectric response in Pb,,Zr,Ti...O3­Pb2Ru2O6.5 all-ceramic percolative composite Vid Bobnar response of a composite comprising a conductive filler embedded in a dielectric matrix--the effective­9 and inorganic composites comprising metal particles dis- persed in a dielectric matrix10­14 have been developed

  13. PVP-Assisted ZrO2 coating on LiMn2O4 spinel cathode nanoparticles prepared by MnO2 nanowire templates

    E-Print Network [OSTI]

    Cho, Jaephil

    solution. Upon annealing at 600 °C in air, an amorphous ZrO2 nanoscale coating layer was obtained [5­10]. Although Li-ion batteries are attractive power-storage devices that have high energy density metal oxide coatings have been reported, studies to improve both the rate capabilities of spinel LiMn2O4

  14. Strong blue and white photoluminescence emission of BaZrO{sub 3} undoped and lanthanide doped phosphor for light emitting diodes application

    SciTech Connect (OSTI)

    Romero, V.H. [Centro de Investigaciones en Optica, A. P. 1-948, Leon Gto., 37160 (Mexico)] [Centro de Investigaciones en Optica, A. P. 1-948, Leon Gto., 37160 (Mexico); De la Rosa, E., E-mail: elder@cio.mx [Centro de Investigaciones en Optica, A. P. 1-948, Leon Gto., 37160 (Mexico); Salas, P. [Centro de Fisica Aplicada y Tecnologia Avanzada, Universidad Nacional Autonoma de Mexico, A.P. 1-1010, Queretaro, Qro. 76000 (Mexico)] [Centro de Fisica Aplicada y Tecnologia Avanzada, Universidad Nacional Autonoma de Mexico, A.P. 1-1010, Queretaro, Qro. 76000 (Mexico); Velazquez-Salazar, J.J. [Department of Physics and Astronomy, The University of Texas at San Antonio One UTSA Circle, San Antonio TX 78249 (United States)] [Department of Physics and Astronomy, The University of Texas at San Antonio One UTSA Circle, San Antonio TX 78249 (United States)

    2012-12-15T23:59:59.000Z

    In this paper, we report the obtained strong broadband blue photoluminescence (PL) emission centered at 427 nm for undoped BaZrO{sub 3} observed after 266 nm excitation of submicron crystals prepared by hydrothermal/calcinations method. This emission is enhanced with the introduction of Tm{sup 3+} ions and is stronger than the characteristic PL blue emission of such lanthanide. The proposed mechanism of relaxation for host lattice emission is based on the presence of oxygen vacancies produced during the synthesis process and the charge compensation due to the difference in the electron valence between dopant and substituted ion in the host. Brilliant white light emission with a color coordinate of (x=0.29, y=0.32) was observed by combining the blue PL emission from the host with the green and red PL emission from Tb{sup 3+} and Eu{sup 3+} ions, respectively. The color coordinate can be tuned by changing the ratio between blue, green and red band by changing the concentration of lanthanides. - Graphical abstract: Strong blue emission from undoped BaZrO{sub 3} phosphor and white light emission by doping with Tb{sup 3+} (green) and Eu{sup 3+} (red) after 266 nm excitation. Highlights: Black-Right-Pointing-Pointer Blue emission from BaZrO{sub 3} phosphor. Black-Right-Pointing-Pointer Blue emission enhanced with Tm{sup 3+}. Black-Right-Pointing-Pointer White light from BaZrO{sup 3+} phosphor.

  15. A Novel Combustion Synthesis Preparation of CuO/ZnO/ZrO2/Pd for Oxidative Hydrogen Production from Methanol

    E-Print Network [OSTI]

    Mukasyan, Alexander

    cells using hydrogen as fuel are efficient, quiet, and have near zero harmful emissions. Elemental fuel cells that use precious metal catalysts such as platinum require hydrogen fuel which contains lessA Novel Combustion Synthesis Preparation of CuO/ZnO/ZrO2/Pd for Oxidative Hydrogen Production from

  16. The ternary silicide ZrPd{sub 3}Si{sub 3}, a stacking variant of the {alpha}-FeSi{sub 2} and Re{sub 3}B structure types

    SciTech Connect (OSTI)

    Wang, M.; Mar, A.

    1999-11-01T23:59:59.000Z

    The ternary zirconium palladium silicide ZrPd{sub 3}Si{sub 3} has been synthesized by arc-melting of the elemental components. It adopts a new structure type and crystallizes in the orthorhombic space group Cmcm with a = 3.8127(4){angstrom}, b = 15.551(1){angstrom}, c = 7.0390(5){angstrom}, and Z = 4 (Pearson symbol oC28). The structure can be regarded as being built up of Re{sub 3}B-type slabs of composition Pd{sub 3}Si alternating with {alpha}-FeSi{sub 2} slabs of composition ZrSi{sub 2}. Notable features include the presence of Si{sub 2} pairs, square pyramidal and tetrahedral coordination of Pd centers by Si atoms, an unusual distorted cubic coordination of the Zr atoms by the Si{sub 2} pairs, and an extensive network of Zr-Zr, Zr-Pd, and Pd-Pd metal-metal bonds. ZrPd{sub 3}Si{sub 3} is weakly metallic with a room-temperature resistivity of 1.7 x 10{sup {minus}3} {Omega} cm. Extended Hueckel band structure calculations confirm the metallic behavior; support the simultaneous existence of strong metal-metal, metal-nonmetal, and nonmetal-nonmetal bonding; and suggest a reduced state for the Pd atoms resulting from electron transfer from the Si atoms.

  17. Ab initio molecular dynamics simulations of ion-solid interactions in Gd2Zr2O7 and Gd2Ti2O7

    SciTech Connect (OSTI)

    Wang, X J [University of Electronic Science and Technology of China (UESTC); Xiao, Haiyan [University of Tennessee, Knoxville (UTK); Zu, X T [University of Electronic Science and Technology of China (UESTC); Zhang, Yanwen [ORNL; Weber, William J [ORNL

    2013-01-01T23:59:59.000Z

    The development of ab initio molecular dynamics (AIMD) method has made it a powerful tool in describing ion-solid interactions in materials, with identification determination of threshold displacement energies with ab initio accuracy, and prediction of new mechanism for defect generation and new defective states that are different from classical molecular dynamics (MD) simulations. In the present work, this method is employed to study the low energy recoil events in Gd2Zr2O7 and Gd2Ti2O7. The weighted average threshold displacement energies in Gd2Zr2O7 are determined to be 38.8 eV for Gd, 41.4 eV for Zr, 18.6 eV for O48f, and 15.6 eV for O8b, which are smaller than the respective values of 41.8, >53.8, 22.6 and 16.2 eV in Gd2Ti2O7. It reveals that all the ions in Gd2Zr2O7 are more easily displaced than those in Gd2Ti2O7, and anion order-disorder are more likely to be involved in the displacement events than cation disordering. The average charge transfer from the primary knock-on atom to its neighbors is estimated to be ~0.15, ~0.11-0.27 and ~0.1-0.13 |e| for Gd, Zr (or Ti), and O, respectively. Negligence of the charge transfer in the interatomic potentials may result in the larger threshold displacement energies in classical MD.

  18. Impact of SF{sub 6} plasma treatment on performance of TaN-HfO{sub 2}-InP metal-oxide-semiconductor field-effect transistor

    SciTech Connect (OSTI)

    Wang Yanzhen; Chen Yenting; Zhao Han; Xue Fei; Zhou Fei; Lee, Jack C. [Department of Electrical and Computer Engineering, Microelectronics Research Center, University of Texas at Austin, Austin, Texas 78758 (United States)

    2011-01-24T23:59:59.000Z

    In this work, the experimental impact of SF{sub 6} plasma treatment on the performance of InP metal-oxide-semiconductor field-effect transistors is presented. S and F are incorporated into atomic layer deposited HfO{sub 2} via postgate SF{sub 6} plasma treatment. The decreased subthreshold swing, gate leakage (I{sub g}), and increased effective channel mobility ({mu}{sub eff}) indicate that better interface and bulk oxide quality have been achieved with SF{sub 6} plasma treatment due to the formation of stronger Hf-F bonds. Drive current (I{sub d}), transconductance (G{sub m}), and effective channel mobility ({mu}{sub eff}) are improved by 22.3%, 35%, and 35%, respectively, compared with those of control devices.

  19. Crystal structure and antiferromagnetic ordering of quasi-2D [Cu(HF{sub 2})(pyz){sub 2}]TaF{sub 6} (pyz = pyrazine).

    SciTech Connect (OSTI)

    Manson, J. L.; Schlueter, J. A.; McDonald, R. D.; Singleton, J.; Materials Science Division; Eastern Washington Univ.; LANL

    2010-04-01T23:59:59.000Z

    The crystal structure of the title compound was determined by X-ray diffraction at 90 and 295 K. Copper(II) ions are coordinated to four bridging pyz ligands to form square layers in the ab-plane. Bridging HF{sub 2}{sup -} ligands join the layers together along the c-axis to afford a tetragonal, three-dimensional (3D) framework that contains Taf{sub 6}{sup -} anions in every cavity. At 295 K, the pyz rings lie exactly perpendicular to the layers and cooling to 90 K induces a canting of those rings. Magnetically, the compound exhibits 2D antiferromagnetic correlations within the 2D layers with an exchange interaction of -13.1(1) K. Weak interlayer interactions, as mediated by Cu-F-H-F-Cu, leads to long-range magnetic order below 4.2 K. Pulsed-field magnetization data at 0.5 K show a concave curvature with increasing B and reveal a saturation magnetization at 35.4 T.

  20. Specification of CuCrZr Alloy Properties after Various Thermo-Mechanical Treatments and Design Allowables including Neutron Irradiation Effects

    SciTech Connect (OSTI)

    Barabash, Vladimir [ITER Organization, Saint Paul Lez Durance, France] [ITER Organization, Saint Paul Lez Durance, France; Kalinin, G. M. [RDIPE, P.O. Box 788, 101000 Moscow, Russia] [RDIPE, P.O. Box 788, 101000 Moscow, Russia; Fabritsiev, Sergei A. [D.V. Efremov Scientific Research Institute, St. Petersburg, Russia] [D.V. Efremov Scientific Research Institute, St. Petersburg, Russia; Zinkle, Steven J [ORNL] [ORNL

    2012-01-01T23:59:59.000Z

    Precipitation hardened CuCrZr alloy is a promising heat sink and functional material for various applica- tions in ITER, for example the first wall, blanket electrical attachment, divertor, and heating systems. Three types of thermo-mechanical treatment were identified as most promising for the various applica- tions in ITER: solution annealing, cold working and ageing; solution annealing and ageing; solution annealing and ageing at non-optimal condition due to specific manufacturing processes for engineer- ing-scale components. The available data for these three types of treatments were assessed and mini- mum tensile properties were determined based on recommendation of Structural Design Criteria for the ITER In-vessel Components. The available data for these heat treatments were analyzed for assess- ment of neutron irradiation effect. Using the definitions of the ITER Structural Design Criteria the design allowable stress intensity values are proposed for CuCrZr alloy after various heat treatments.

  1. Trapping characteristics of Al{sub 2}O{sub 3}/HfO{sub 2}/SiO{sub 2} stack structure prepared by low temperature in situ oxidation in dc sputtering

    SciTech Connect (OSTI)

    Chang, C.-H.; Hwu, J.-G. [Graduate Institute of Electronics Engineering/Department of Electrical Engineering, National Taiwan University, Taipei, Taiwan 10617 (China)

    2009-05-01T23:59:59.000Z

    In this work, a dielectric stack with Al{sub 2}O{sub 3}/HfO{sub 2}/SiO{sub 2} (1.8 nm/1.6 nm/2.5 nm) trilayer structure prepared by low temperature in situ natural oxidation during dc sputtering is investigated. We study the electrical characteristics, including the dielectric leakage of 10{sup -8} A/cm{sup 2} at V{sub g}=-2 V, the current transport mechanism and trap distributions through the trilayer dielectric stack. The Fowler-Nordheim barrier height of the prepared Al{sub 2}O{sub 3}(phi{sub FN,Al{sub 2O{sub 3}}}) was extracted as 3.06+-0.15 eV. The current variation ratios [DELTAJ{sub g}/J{sub g}(0)] during constant voltage stressing were found to decrease with raising gate stress voltages for the trilayer stack in comparison with that [DELTAJ{sub g}/J{sub g}(0)] increase with raising gate stress voltages for the two-layer HfO{sub 2}/SiO{sub 2} stack. Shallow traps located in HfO{sub 2} were supposed to be major trapping centers within the trilayer stack. The proposed method of in situ oxidation during dc sputtering is of merit and low in process temperature. The trilayer dielectric stacks are an alternative option for nonvolatile memory application, especially under the consideration of low temperature limitation.

  2. Study on the Ge{sub 1?x}Sn{sub x}/HfO{sub 2} interface and its impacts on Ge{sub 1?x}Sn{sub x} tunneling transistor

    SciTech Connect (OSTI)

    Qiu, Yingxin; Wang, Runsheng, E-mail: ruhuang@pku.edu.cn, E-mail: r.wang@pku.edu.cn; Huang, Qianqian; Huang, Ru, E-mail: ruhuang@pku.edu.cn, E-mail: r.wang@pku.edu.cn [Key Laboratory of Microelectronic Devices and Circuits, Institute of Microelectronics, Peking University, Beijing 100871 (China)

    2014-06-21T23:59:59.000Z

    In this paper, we employ first-principle calculation to investigate the Ge{sub 1?x}Sn{sub x}/HfO{sub 2} interface, and then evaluate its impacts on Ge{sub 1?x}Sn{sub x} tunneling field-effect transistor (TFET). First-principle calculations of Ge{sub 1?x}Sn{sub x}/HfO{sub 2} interfaces in the oxygen-rich process atmosphere indicate that the interface states originate from the Ge and Sn dangling bond, rather than Hf-bond. The total density of state shows that there are more interface states in the semiconductor bandgap with increasing Sn fraction. By further incorporating the material and interface parameters from density functional theory calculation into advanced device simulation, the electrical characteristics of Ge{sub 1?x}Sn{sub x} TFET are investigated. Removing the Sn atom from the first atom layer of Ge{sub 1?x}Sn{sub x} in device processes is found to be beneficial to reduce the degradations. For the degradation mechanisms, the trap-assisted-tunneling is the dominant mechanism at the low Sn fraction, and enhanced Shockley-Read-Hall recombination induced by traps becomes the dominant mechanism with increasing Sn fraction. The results are helpful for the interface optimization of Ge{sub 1?x}Sn{sub x} TFET.

  3. Effect of current compliance and voltage sweep rate on the resistive switching of HfO{sub 2}/ITO/Invar structure as measured by conductive atomic force microscopy

    SciTech Connect (OSTI)

    Wu, You-Lin, E-mail: ylwu@ncnu.edu.tw; Liao, Chun-Wei [Department of Electrical Engineering, National Chi Nan University, Puli, Nantou, Taiwan (China); Ling, Jing-Jenn [Department of Applied Materials and Optoelectronic Engineering, National Chi Nan University, Puli, Nantou, Taiwan (China)

    2014-06-16T23:59:59.000Z

    The electrical characterization of HfO{sub 2}/ITO/Invar resistive switching memory structure was studied using conductive atomic force microscopy (AFM) with a semiconductor parameter analyzer, Agilent 4156C. The metal alloy Invar was used as the metal substrate to ensure good ohmic contact with the substrate holder of the AFM. A conductive Pt/Ir AFM tip was placed in direct contact with the HfO{sub 2} surface, such that it acted as the top electrode. Nanoscale current-voltage (I-V) characteristics of the HfO{sub 2}/ITO/Invar structure were measured by applying a ramp voltage through the conductive AFM tip at various current compliances and ramp voltage sweep rates. It was found that the resistance of the low resistance state (RLRS) decreased with increasing current compliance value, but resistance of high resistance state (RHRS) barely changed. However, both the RHRS and RLRS decreased as the voltage sweep rate increased. The reasons for this dependency on current compliance and voltage sweep rate are discussed.

  4. Systematic Study of the Effect of La2O3 Incorporation on the Flatband Voltage and Si Band Bending in the TiN/HfO2 /SiO2 /p-Si Stack

    SciTech Connect (OSTI)

    M Di; E Bersch; R Clark; S Consiglio; G Leusink; A Diebold

    2011-12-31T23:59:59.000Z

    Recent studies have shown that La{sub 2}O{sub 3} films can be used to adjust the threshold voltage (V{sub t}) of NMOS Hf-based high-k/metal gate devices to desirable values, and a dipole at the high-k/SiO{sub 2} interface has been proposed to explain the V{sub t} shifts. In order to investigate the mechanism of the V{sub t} shift further, we have measured the flatband voltage (V{sub fb}) and Si band bending of technologically relevant TiN/HfO{sub 2}/La{sub 2}O{sub 3}/SiO{sub 2}/p-Si stacks where the thickness and position of the La{sub 2}O{sub 3} layer have been systematically varied. We observed systematic changes in V{sub fb}, Si band bending and the HfO{sub 2}-Si valence band offset as a function of La{sub 2}O{sub 3} layer thickness and position. These changes can be explained by a band alignment model that includes a dipole at the high-k/SiO{sub 2} interface, thus supporting the work of previous authors. In addition, we have derived the theoretical relationship between V{sub fb} and Si band bending, which agrees well with our experimental measurements.

  5. Surface Passivation of Nanoporous TiO2 via Atomic Layer Deposition of ZrO2 for Solid-State Dye-Sensitized Solar Cell Applications

    E-Print Network [OSTI]

    to the spiro-OMeTAD. Introduction Dye-sensitized solar cells (DSCs) based on mesoporous titania and liquidSurface Passivation of Nanoporous TiO2 via Atomic Layer Deposition of ZrO2 for Solid-State Dye-Sensitized Solar Cell Applications Tina C. Li, Ma´rcio S. Go´es,,§ Francisco Fabregat-Santiago,*, Juan Bisquert

  6. Thermodynamic Assessment of Hot Corrosion Mechanisms of Superalloys Hastelloy N and Haynes 242 in Eutectic Mixture of Molten Salts KF and ZrF4

    SciTech Connect (OSTI)

    Michael V. Glazoff

    2012-02-01T23:59:59.000Z

    The KF - ZrF4 system was considered for the application as a heat exchange agent in molten salt nuclear reactors (MSRs) beginning with the work carried out at ORNL in early fifties. Based on a combination of excellent properties such as thermal conductivity, viscosity in the molten state, and other thermo-physical and rheological properties, it was selected as one of possible candidates for the nuclear reactor secondary heat exchanger loop.

  7. Influence of crystalline phase and defects in the ZrO{sub 2} nanoparticles synthesized by thermal plasma route on its photocatalytic properties

    SciTech Connect (OSTI)

    Nawale, Ashok B.; Kanhe, Nilesh S.; Bhoraskar, S.V. [Department of Physics, University of Pune, Pune 411007 (India)] [Department of Physics, University of Pune, Pune 411007 (India); Mathe, V.L., E-mail: vlmathe@physics.unipune.ac.in [Department of Physics, University of Pune, Pune 411007 (India); Das, A.K. [Laser and Plasma Technology Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India)] [Laser and Plasma Technology Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India)

    2012-11-15T23:59:59.000Z

    Graphical abstract: Thermal plasma synthesized nanophase zirconia showing the blue shift in the band gap of monoclinic phase as found from the photoabsorption spectroscopy was found to be the dominant parameter for the enhancement in its photocatalytic activity. The existence of different defect states and their concentration in as synthesized samples also inferred from the photoabsorption measurements were also found to be responsible for the enhanced photocatalytic activity of the samples. Highlights: ? Phase controlled structural formation of nanophase ZrO{sub 2} by thermal plasma route. ? Enhanced photocatalytic degradation rate of methylene blue dye. ? The blue shift in the band gap of monoclinic phase of nanocrystalline ZrO{sub 2}. ? Existence of different defect states in the as synthesized nano phase ZrO{sub 2}. ? Several competing processes which controls the photocatalytic degradation rate. -- Abstract: The photocatalytic activity of pure ZrO{sub 2} samples, prepared by a thermal plasma route, and characterized by X-ray diffraction technique was tested for the degradation of methylene blue, which is known to be a hazardous dye. Although, all these samples synthesized at different operating pressures of the thermal plasma reactor showed the photocatalytic activity; the sample synthesized at 1.33 bar of operating pressure showed the highest photocatalytic activity. The blue shift in the band gap of monoclinic phase, as observed from the photo-absorption spectroscopy, may be attributed to the enhanced photocatalytic activity. The existence of different defect states and their concentration as, inferred from the photo-absorption measurements were also found to be responsible for the enhanced photocatalytic activity of the as synthesized samples.

  8. Low thermal expansion behavior and thermal durability of ZrTiO4Al2TiO5Fe2O3 ceramics between 750 and 1400

    E-Print Network [OSTI]

    Cao, Guozhong

    2002 Abstract The thermal-shock-resistant materials in the system Al2TiO5­ZrTiO4 (ZAT) were synthesized Aluminum titanate (Al2TiO5) is well-known as an excellent thermal shock-resistant material, resulting from. All rights reserved. Keywords: Al2TiO5; Thermal expansion; Thermal shock resistance 1. Introduction

  9. A Method to Increase Current Density in a Mono Element Internal Tin Processed Superconductor Utilizing Zr Oxide to Refine Grain Size

    SciTech Connect (OSTI)

    Bruce A. Zeitlin, Eric Gregory

    2008-04-07T23:59:59.000Z

    The effect of Oxygen on (Nb1Zr)3Sn multifilament conductors manufactured by the Mono Element Internal Tin (MEIT) process was explored to improve the current density by refining the grain size. This followed work first done by General Electric on the Nb3Sn tape process. Techniques to fabricate the more difficult Nb1Zr composites are described and allowed fabrication of long lengths of .254 mm diameter wire from an 88.9 mm diameter billet. Oxygen was incorporated through the use of SnO2 mixed with tin powder and incorporated into the core. These were compared to samples with Ti+Sn and Cu+Sn cores. Heat treatments covered the range of 700 C to 1000 C. Current density vs. H, grain size, and reaction percentages are provided for the materials tested. The Oxygen gave superior results in the temperature range of 815-1000 C. It also stabilized the filament geometry of the array in comparison to the other additions at the higher temperatures. At 815 C a peak in layer Jc yielded values of 2537 A/mm2 at 12 T and 1353 A/mm2 at 15T, 8-22% and 30-73% greater respectively than 700 C values. Results with Oxygen at high temperature show the possibility of high speed continuous reaction of the composite versus the current batch or react in place methods. In general the Ti additions gave superior results at the lower reaction temperature. Future work is suggested to determine if the 815 C reaction temperature can lead to higher current density in high tin (Nb1Zr+Ox)3Sn conductors. A second technique incorporated oxygen directly into the Nb1Zr rods through heat treatment with Nb2O5 at 1100 C for 100 hours in vacuum prior to extrusion. The majority of the filaments reduced properly in the composite but some local variations in hardness led to breakage at smaller diameters.

  10. Characterization of the reaction products that develop in the processing of Al{sub 2}O{sub 3}/BaZrO{sub 3} laminated composites

    SciTech Connect (OSTI)

    Gladysz, G.M. [Youngstown State Univ., OH (United States). Dept. of Chemical Engineering] [Youngstown State Univ., OH (United States). Dept. of Chemical Engineering; Schmuecker, M.; Schneider, H. [German Aerospace Establishment, Cologne (Germany)] [German Aerospace Establishment, Cologne (Germany); Chawla, K.K. [Univ. of Alabama, Birmingham, AL (United States). Dept. of Materials and Mechanical Engineering] [Univ. of Alabama, Birmingham, AL (United States). Dept. of Materials and Mechanical Engineering; Joslin, D.L.; Ferber, M.K. [Oak Ridge National Lab., TN (United States)] [Oak Ridge National Lab., TN (United States)

    1998-04-01T23:59:59.000Z

    The absence of a chemical reaction at an interface is conventionally thought to be an important criterion in producing a tough ceramic matrix composite (CMC). As a result of this criterion, interphases in CMCs were chosen on the basis of their chemical reactivity. A weak interface results in crack deflection, crack bridging, and, in fiber-reinforced ceramics, fiber pullout, resulting in an increased fracture toughness. In this paper, the authors present microstructural observations on alumina (Al{sub 2}O{sub 3})-barium zirconate (BaZrO{sub 3}) laminated composites wherein the reaction products that develop during processing resulted in sharp interfaces and appear to be weak enough to deflect cracks. These in situ reaction products in Al{sub 2}O{sub 3}-BaZrO{sub 3} laminated composites were characterized with the use of a scanning electron microscope, an electron microprobe, and a transmission electron microscope. The phases that develop, ZrO{sub 2}, BaO{center_dot}Al{sub 2}O{sub 3}, and BaO{center_dot}6 Al{sub 2}O{sub 3}, produced sharp interfaces and are arranged in a sequence that could be predicted by using information from the phase diagram.

  11. Effective passivation of In{sub 0.2}Ga{sub 0.8}As by HfO{sub 2} surpassing Al{sub 2}O{sub 3} via in-situ atomic layer deposition

    SciTech Connect (OSTI)

    Chang, Y. H.; Chiang, T. H. [Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Lin, C. A.; Liu, Y. T.; Lin, H. Y.; Huang, M. L.; Kwo, J. [Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Lin, T. D.; Hong, M. [Graduate Institute of Applied Physics and Department of Physics, National Taiwan University, Taipei 10617, Taiwan (China); Pi, T. W. [National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan (China)

    2012-10-22T23:59:59.000Z

    High {kappa} gate dielectrics of HfO{sub 2} and Al{sub 2}O{sub 3} were deposited on molecular beam epitaxy-grown In{sub 0.2}Ga{sub 0.8}As pristine surface using in-situ atomic-layer-deposition (ALD) without any surface treatment or passivation layer. The ALD-HfO{sub 2}/p-In{sub 0.2}Ga{sub 0.8}As interface showed notable reduction in the interfacial density of states (D{sub it}), deduced from quasi-static capacitance-voltage and conductance-voltage (G-V) at room temperature and 100 Degree-Sign C. More significantly, the midgap peak commonly observed in the D{sub it}(E) of ALD-oxides/In{sub 0.2}Ga{sub 0.8}As is now greatly diminished. The midgap D{sub it} value decreases from {>=}15 Multiplication-Sign 10{sup 12} eV{sup -1} cm{sup -2} for ALD-Al{sub 2}O{sub 3} to {approx}2-4 Multiplication-Sign 10{sup 12} eV{sup -1} cm{sup -2} for ALD-HfO{sub 2}. Further, thermal stability at 850 Degree-Sign C was achieved in the HfO{sub 2}/In{sub 0.2}Ga{sub 0.8}As, whereas C-V characteristics of Al{sub 2}O{sub 3}/p-In{sub 0.2}Ga{sub 0.8}As degraded after the high temperature annealing. From in-situ x-ray photoelectron spectra, the AsO{sub x}, which is not the oxidized state from the native oxide, but is an induced state from adsorption of trimethylaluminum and H{sub 2}O, was found at the ALD-Al{sub 2}O{sub 3}/In{sub 0.2}Ga{sub 0.8}As interface, while that was not detected at the ALD-HfO{sub 2}/In{sub 0.2}Ga{sub 0.8}As interface.

  12. Shell Model Monte Carlo method in the $pn$-formalism and applications to the Zr and Mo isotopes

    E-Print Network [OSTI]

    C. Ozen; D. J. Dean

    2005-08-05T23:59:59.000Z

    We report on the development of a new shell-model Monte Carlo algorithm which uses the proton-neutron formalism. Shell model Monte Carlo methods, within the isospin formulation, have been successfully used in large-scale shell-model calculations. Motivation for this work is to extend the feasibility of these methods to shell-model studies involving non-identical proton and neutron valence spaces. We show the viability of the new approach with some test results. Finally, we use a realistic nucleon-nucleon interaction in the model space described by (1p_1/2,0g_9/2) proton and (1d_5/2,2s_1/2,1d_3/2,0g_7/2,0h_11/2) neutron orbitals above the Sr-88 core to calculate ground-state energies, binding energies, B(E2) strengths, and to study pairing properties of the even-even 90-104 Zr and 92-106 Mo isotope chains.

  13. PHYSICAL REVIEW B 83, 115329 (2011) Diffusion and interface growth in hafnium oxide and silicate ultrathin films on Si(001)

    E-Print Network [OSTI]

    Garfunkel, Eric

    PHYSICAL REVIEW B 83, 115329 (2011) Diffusion and interface growth in hafnium oxide and silicate­oxide­semiconductor (CMOS) technology necessary.1,2 Transition metal (Hf, Zr, La) oxides, silicates, and ternary Hf to be desirable to have at least one monolayer of SiO2 at the dielectric/Si interface. The Hf oxide (silicate

  14. Nonadiabatic reactive scattering in atom+triatom systems: Nascent rovibronic distributions in F+H{sub 2}O{yields}HF+OH

    SciTech Connect (OSTI)

    Ziemkiewicz, Michael; Nesbitt, David J. [JILA, National Institute of Standards and Technology, University of Colorado, Boulder, Colorado 80309-0440 (United States) and Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0440 (United States)

    2009-08-07T23:59:59.000Z

    Crossed supersonic jet studies of F+H{sub 2}O{yields}HF+OH({sup 2}{Pi}{sub 3/2},{sup 2}{Pi}{sub 1/2}) have been performed under low density, single collision conditions at E{sub com}=6(2) kcal/mol, yielding rotational, vibrational, and spin-orbit state distributions in the nascent OH product by laser induced fluorescence methods. The lowest reaction barriers on the ground and first excited electronic surfaces are {Delta}E{approx_equal}4 kcal/mol and {Delta}E{approx_equal}25 kcal/mol, correlating with OH({sup 2}{Pi}{sub 3/2}) and OH({sup 2}{Pi}{sub 1/2}), respectively. Although only reactions on the ground state potential are Born-Oppenheimer allowed at the experimental collision energies, both ground and excited spin-orbit OH products are observed in a {sup 2}{Pi}{sub 3/2}:{sup 2}{Pi}{sub 1/2}=69(1)%:31(1)% branching ratio. This indicates the presence of strong nonadiabatic surface hopping interactions, in agreement with previous results for the F+D{sub 2}O{yields}DF+OD reaction. Despite clear differences in the rotational distributions between F+H{sub 2}O and F+D{sub 2}O isotopic reactions, the overall electronic branching into spin-orbit manifolds is nearly identical for both OH and OD products. Furthermore, when plotted versus total electronic+rotational energy, the nascent OH and OD populations each lie on single curves, with pronounced kinks in the Boltzmann plots suggestive of microscopic branching in the reaction dynamics. Such an equivalence of electronic and rotational energy release in the OH/OD products is consistent with predominantly nonadiabatic processes taking place in the immediate post-transition state region rather than asymptotically in the exit channel.

  15. Growth-induced non-planar magnetic anisotropy in FeCoZr-CaF{sub 2} nanogranular films: Structural and magnetic characterization

    SciTech Connect (OSTI)

    Kasiuk, J. V.; Fedotova, J. A. [NC PHEP Belarusian State University, 220040 Minsk (Belarus); Przewoznik, J., E-mail: januszp@agh.edu.pl; Zukrowski, J.; Sikora, M.; Kapusta, Cz. [Department of Solid State Physics, Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, al. Mickiewicza 30, 30-059 Krakow (Poland); Grce, A. [VIN?A Institute of Nuclear Sciences, Belgrade University, P.O. Box 522, 11001 Belgrade (Serbia); Milosavljevi?, M. [VIN?A Institute of Nuclear Sciences, Belgrade University, P.O. Box 522, 11001 Belgrade (Serbia); Advanced Technology Institute, Faculty of Engineering and Physical Sciences, University of Surrey, Guildford, Surrey GU2 7XH (United Kingdom)

    2014-07-28T23:59:59.000Z

    The relation between nanoscale structure, local atomic order and magnetic properties of (FeCoZr){sub x}(CaF{sub 2}){sub 100?x} (29???x???73 at.?%) granular films is studied as a function of metal/insulator fraction ratio. The films of a thickness of 1–6??m were deposited on Al-foils and glass-ceramic substrates, by ion sputtering of targets of different metal/insulator contents. Structural characterization with X-ray and electron diffraction as well as transmission electron microscopy revealed that the films are composed of isolated nanocrystalline bcc ?-FeCo(Zr) alloy and insulating fcc CaF{sub 2} matrix. They grow in a columnar structure, where elongated metallic nanograins are arranged on top of each other within the columns almost normal to the substrate surface. Mössbauer spectroscopy and magnetometry results indicate that their easy magnetization axes are oriented at an angle of 65°–74° to the surface in films with x between 46 and 74, above the electrical percolation threshold, which is attributed to the growth-induced shape anisotropy. Interatomic distances characteristic for metallic state of ?-FeCo(Zr) nanograins were revealed by X-ray Absorption Spectroscopy. The results show a lack of surface oxidation of the alloy nanograins, so the growth-induced orientation of nanograins in the films cannot be attributed to this effect. The study is among the first to report a growth-induced non-planar magnetic anisotropy in metal/insulator granular films above the percolation threshold and to reveal the origin of it.

  16. Pion-nucleus elastic scattering on 12C, 40Ca, 90Zr, and 208Pb at 400 and 500 MeV

    E-Print Network [OSTI]

    George Kahrimanis; George Burleson; C. M. Chen; B. C. Clark; Kalvir Dhuga; D. J. Ernst; J. A. Faucett; H. T. Fortune; S. Hama; Ahmed Hussein; M. F. Jiang; K. W. Johnson; L. Kurth Kerr; Scott Mathews; John McGill; C. Fred Moore; Shaul Mordechai; Christopher L. Morris; John O'Donnell; Mike Snell; Mohini Rawool-Sullivan; L. Ray; Charles Whitley; Allen L. Williams

    1997-02-25T23:59:59.000Z

    Pion-nucleus elastic scattering at energies above the Delta(1232) resonance is studied using both pi+ and pi- beams on 12C, 40Ca, 90Zr, and 208Pb. The present data provide an opportunity to study the interaction of pions with nuclei at energies where second-order corrections to impulse approximation calculations should be small. The results are compared with other data sets at similar energies, and with four different first-order impulse approximation calculations. Significant disagreement exists between the calculations and the data from this experiment.

  17. Thickness dependence of magnetoelectric response for composites of Pb(Zr{sub 0.52}Ti{sub 0.48})O{sub 3} films on CoFe{sub 2}O{sub 4} ceramic substrates

    SciTech Connect (OSTI)

    Wang, Jing, E-mail: wang-jing@nuaa.edu.cn; Zhu, Kongjun [State Key Laboratory of Mechanics and Control of Mechanical Structures, College of Aerospace Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China); Wu, Xia; Deng, Chaoyong [School of Electronics and Information Engineering, Guizhou University, Guiyang 550025 (China); Peng, Renci; Wang, Jianjun [School of Materials Science and Engineering, and State Key Lab of New Ceramics and Fine Processing, Tsinghua University, Beijing 100084 (China)

    2014-08-15T23:59:59.000Z

    Using chemical solution spin-coating we grew Pb(Zr{sub 0.52}Ti{sub 0.48})O{sub 3} films of different thicknesses on highly dense CoFe{sub 2}O{sub 4} ceramics. X-ray diffraction revealed no other phases except Pb(Zr{sub 0.52}Ti{sub 0.48})O{sub 3} and CoFe{sub 2}O{sub 4}. In many of these samples we observed typical ferroelectric hysteresis loops, butterfly-shaped piezoelectric strains, and the magnetic-field-dependent magnetostriction. These behaviors caused appreciable magnetoelectric responses based on magnetic-mechanical-electric coupling. Our results indicated that the thickness of the Pb(Zr{sub 0.52}Ti{sub 0.48})O{sub 3} film was important in obtaining strong magnetoelectric coupling.

  18. Band alignment of HfO{sub 2}/Al{sub 0.25}Ga{sub 0.75}N determined by x-ray photoelectron spectroscopy: Effect of SiH{sub 4} surface treatment

    SciTech Connect (OSTI)

    Samuel Owen, Man Hon, E-mail: m.owen.sg@ieee.org, E-mail: yeo@ieee.org; Amin Bhuiyan, Maruf; Zhou, Qian; Yeo, Yee-Chia, E-mail: m.owen.sg@ieee.org, E-mail: yeo@ieee.org [Department of Electrical and Computer Engineering, National University of Singapore, Singapore 119260 (Singapore); Zhang, Zheng; Sheng Pan, Ji [Institute of Materials Research and Engineering, A-STAR (Agency for Science, Technology and Research), 3 Research Link, Singapore 117602 (Singapore)

    2014-03-03T23:59:59.000Z

    The band-alignment of atomic layer deposited (ALD)-HfO{sub 2}/Al{sub 0.25}Ga{sub 0.75}N was studied by high resolution x-ray photoelectron spectroscopy measurements for both the non-passivated and SiH{sub 4} passivated AlGaN surfaces. The valence band offset and the conduction band offset for the ALD-HfO{sub 2}/Al{sub 0.25}Ga{sub 0.75}N interface were found to be 0.43?eV and 1.47?eV, respectively, for the non-passivated sample, and 0.59?eV and 1.31?eV, respectively, for the SiH{sub 4}-passivated sample. The difference in the band alignment is dominated by the band bending or band shift in the AlGaN substrate as a result of the different interlayers formed by the two surface preparations.

  19. In–Ga–Zn–O thin film transistor with HfO{sub 2} gate insulator prepared using various O{sub 2}/(Ar + O{sub 2}) gas ratios

    SciTech Connect (OSTI)

    Jo, Young Je [WCU Department of Printed Electronics, Sunchon National University, Chonnam 540-742 (Korea, Republic of)] [WCU Department of Printed Electronics, Sunchon National University, Chonnam 540-742 (Korea, Republic of); Lee, In-Hwan [School of Advanced Materials Engineering, Chonbuk National University, Chonju 561-756 (Korea, Republic of)] [School of Advanced Materials Engineering, Chonbuk National University, Chonju 561-756 (Korea, Republic of); Kwak, Joon Seop, E-mail: jskwak@sunchon.ac.kr [WCU Department of Printed Electronics, Sunchon National University, Chonnam 540-742 (Korea, Republic of)

    2012-10-15T23:59:59.000Z

    We have investigated the effect of the deposition of an HfO{sub 2} thin film as a gate insulator with different O{sub 2}/(Ar + O{sub 2}) gas ratios using RF magnetron sputtering. The HfO{sub 2} thin film affected the device performance of amorphous indium–gallium–zinc oxide transistors. The performance of the fabricated transistors improved monotonously with increasing O{sub 2}/(Ar + O{sub 2}) gas ratio: at a ratio of 0.35, the field effect mobility of the amorphous InGaZnO thin film transistors was improved to 7.54 cm{sup 2}/(V s). Compared to those prepared with an O{sub 2}/(Ar + O{sub 2}) gas ratio of 0.05, the field effect mobility of the amorphous InGaZnO thin film transistors was increased to 1.64 cm{sup 2}/(V s) at a ratio of 0.35. This enhancement in the field effect mobility was attributed to the reduction of the root mean square roughness of the gate insulator layer, which might result from the trap states and surface scattering of the gate insulator layer at the lower O{sub 2}/(Ar + O{sub 2}) gas ratio.

  20. The effect of fluence and irradiation temperature on delayed hydride cracking in Zr-2.5Nb

    SciTech Connect (OSTI)

    Sagat, S.; Coleman, C.E.; Griffiths, M. [AECL Research, Chalk River, Ontario (Canada); Wilkins, B.J.S. [AECL Research, Pinawa, Manitoba (Canada)

    1994-12-31T23:59:59.000Z

    Zirconium alloys are susceptible to a stable cracking process called delayed hydride cracking (DHC). DHC has two stages: (a) crack initiation that requires a minimum crack driving force (the threshold stress intensity factor, K{sub IH}) and (b) stable crack growth that is weakly dependent on K{sub l}. The value of K{sub lH} is an important element in determining the tolerance of components to sharp flaws. The rate of cracking is used in estimating the action time for detecting propagating cracks before they become unstable. Hence, it is important for reactor operators to know how these properties change during service in reactors where the components are exposed to neutron irradiation at elevated temperatures. DHC properties were measured on a number of components, made from the two-phase alloy Zr-2.5 Nb, irradiated at temperatures in the range of 250 to 290 C in fast neutron fluxes (E {>=} 1 MeV) between 1.6 {times} 10{sup 17} and 1.8 {times} 10{sup 18} n/m{sup 2} {center_dot} s to fluences between 0.01 {times} 10{sup 25} and 9.8 {times} 10{sup 25} n/m{sup 2}. The neutron irradiation reduced K{sub IH} by about 20% and increased the velocity of cracking by a factor of about five. The increase in crack velocity was greatest with the lowest irradiation temperature. These changes in the rack velocity by neutron irradiation are explained in terms of the combined effects of irradiation hardening associated with increased -type dislocation density, and {beta}-phase decomposition. While the former process increases crack velocity, the latter process decrease it. The combined contribution is controlled by the irradiation temperature. X-ray diffraction analyses showed that the degree of {beta}-phase decomposition was highest with an irradiation temperature of 290 C while -type dislocation densities were highest with an irradiation temperature of 250 C.

  1. In situ X-ray diffraction strain-controlled study of Ti–Nb–Zr and Ti–Nb–Ta shape memory alloys: crystal lattice and transformation features

    SciTech Connect (OSTI)

    Dubinskiy, S. [École de technologie supérieure, 1100, Notre-Dame Street West, Montreal, Quebec H3C 1K3 (Canada); National University of Science and Technology “MISIS”, 4, Leninskiy prosp., Moscow 119049 (Russian Federation); Prokoshkin, S. [National University of Science and Technology “MISIS”, 4, Leninskiy prosp., Moscow 119049 (Russian Federation); Brailovski, V., E-mail: vladimir.brailovski@etsmtl.ca [École de technologie supérieure, 1100, Notre-Dame Street West, Montreal, Quebec H3C 1K3 (Canada); Inaekyan, K. [École de technologie supérieure, 1100, Notre-Dame Street West, Montreal, Quebec H3C 1K3 (Canada); Korotitskiy, A. [National University of Science and Technology “MISIS”, 4, Leninskiy prosp., Moscow 119049 (Russian Federation)

    2014-02-15T23:59:59.000Z

    Phase and structure transformations in biomedical Ti–21.8Nb–6.0Zr (TNZ) and Ti–19.7Nb–5.8Ta (TNT) shape memory alloys (at.%) under and without load in the ? 150 to 100 °S temperature range are studied in situ using an original tensile module for a low-temperature chamber of an X-ray diffractometer. Alpha?- and beta-phase lattice parameters, the crystallographic resource of recovery strain, phase and structure transformation sequences, and microstress appearance and disappearance are examined, compared and discussed. For both alloys, the crystallographic resource of recovery strain decreases with temperature increase to become 4.5% for TNZ and 2.5% for TNT alloy (at RT). Loading at low temperatures leads to additional ??-phase formation and reorientation. Heating under load, as compared to strain-free heating, affects the reverse transformation sequence of both alloys in different ways. For TNZ alloy, strain-free heating results in simultaneous ??? and ???? transformations, whereas during heating under stress, they are sequential: ? + ???? precedes ????. For TNT alloy, strain-free heating results in reverse ???? transformation, whereas during heating under stress, ???? transformation is preceded by ??-phase reorientation. - Highlights: • Comparative in situ XRD analysis of Ti–Nb–Zr(Ta) shape memory alloys is realized. • Lattice parameters of ?- and ??-phases are calculated in the ? 150 to + 100 °C range. • The higher the temperature, the lower the ???? transformation strain. • Loading at low temperatures results in ??-phase formation and reorientation. • Transformation sequences upon heating with and without loading are different.

  2. Hydrothermal synthesis of yttria stabilized ZrO{sub 2} nanoparticles in subcritical and supercritical water using a flow reaction system

    SciTech Connect (OSTI)

    Hayashi, Hiromichi, E-mail: h-hayashi@aist.go.j [Research Center for Compact Chemical Process, National Institute of Advanced Industrial Science and Technology (AIST), Nigatake 4-2-1, Miyagino-ku, Sendai 983-8551 (Japan); Ueda, Akiko; Suino, Atsuko; Hiro, Kyoko; Hakuta, Yukiya [Research Center for Compact Chemical Process, National Institute of Advanced Industrial Science and Technology (AIST), Nigatake 4-2-1, Miyagino-ku, Sendai 983-8551 (Japan)

    2009-11-15T23:59:59.000Z

    Yttria stabilized zirconia nanoparticles have been prepared by hydrothermal flow reaction system under subcritical and supercritical conditions. ZrO(NO{sub 3}){sub 2}/Y(NO{sub 3}){sub 3} mixed solutions were used as starting materials. Reaction temperature was 300-400 deg. C. Reaction time was adjusted to 0.17-0.35 s. Based on the residual Zr and Y concentrations, the complete conversion of zirconium was achieved irrespective of pH and hydrothermal temperature, whereas the conversion of yttrium increased with an increase in pH and hydrothermal temperature. Stoichiometric solid solution was achieved at pH>8. XRD results revealed that tetragonal zirconia can be formed regardless of yttrium content, where the tetragonality was confirmed by Raman spectroscopy. The average particle size estimated from BET surface area was around 4-6 nm. Dynamic light scattering particle size increased with the solution pH owing to the aggregation of primary particles. TG-DTA analyses revealed that weight losses for adsorbed water and hydroxyl groups decreased with hydrothermal temperature. - Graphical abstract: Nanoparticles of YSZ can be synthesized in subcritical and supercritical water using a hydrothermal flow reaction system. Given is the TEM image of YSZ nanoparticles.

  3. In situ growth of ZrO{sub 2}–Al{sub 2}O{sub 3} nano-crystalline ceramic coatings via micro arc oxidation of aluminum substrates

    SciTech Connect (OSTI)

    Shoaei-Rad, V. [School of Metallurgy and Materials Engineering, Iran University of Science and Technology, P.O. Box 16845-161, Tehran (Iran, Islamic Republic of)] [School of Metallurgy and Materials Engineering, Iran University of Science and Technology, P.O. Box 16845-161, Tehran (Iran, Islamic Republic of); Bayati, M.R., E-mail: mbayati@ncsu.edu [School of Metallurgy and Materials Engineering, Iran University of Science and Technology, P.O. Box 16845-161, Tehran (Iran, Islamic Republic of); Department of Materials Science and Engineering, North Carolina State University, Raleigh 27695-7907, NC (United States); Zargar, H.R. [Department of Metals and Materials Engineering, University of British Columbia, Vancouver, BC V6T 1Z4 (Canada)] [Department of Metals and Materials Engineering, University of British Columbia, Vancouver, BC V6T 1Z4 (Canada); Javadpour, J. [School of Metallurgy and Materials Engineering, Iran University of Science and Technology, P.O. Box 16845-161, Tehran (Iran, Islamic Republic of)] [School of Metallurgy and Materials Engineering, Iran University of Science and Technology, P.O. Box 16845-161, Tehran (Iran, Islamic Republic of); Golestani-Fard, F. [School of Metallurgy and Materials Engineering, Iran University of Science and Technology, P.O. Box 16845-161, Tehran (Iran, Islamic Republic of) [School of Metallurgy and Materials Engineering, Iran University of Science and Technology, P.O. Box 16845-161, Tehran (Iran, Islamic Republic of); Center of Excellence for Advanced Materials, Iran University of Science and Technology, P.O. Box 16845-195, Tehran (Iran, Islamic Republic of)

    2012-06-15T23:59:59.000Z

    Highlights: ? ZrO{sub 2}–Al{sub 2}O{sub 3} layers were fabricated by MAO process. ? A formation mechanism was also proposed. ? Effect of voltage and electrolyte composition on layers properties was studied. -- Abstract: Micro arc oxidation technique was employed to grow zirconia–alumina porous layers. Considering XPS, XRD, and EDX results, the layers mainly consisted of ?-Al{sub 2}O{sub 3}, ?-Al{sub 2}O{sub 3}, monoclinic ZrO{sub 2}, tetragonal ZrO{sub 2}. Fractions of these phases were observed to change based on the fabrication conditions. Zirconia phases formed not only on the surface, but also in the layers depth. Increasing the voltage as well as utilizing thicker electrolytes resulted in higher zirconium concentration. The average crystalline size of the ZrO{sub 2} and the Al{sub 2}O{sub 3} phases was determined as about 57 and 75 nm. AFM studies revealed that the surface roughness increased with voltage and electrolyte concentration. Morphological evaluations, performed by SEM, showed that the microstructure of the layers strongly depended on the synthesis conditions. The layers revealed a porous structure with a pores size of 40–300 nm. Microcracks were observed to appear when the electrolyte concentration and the applied voltage increased. Finally, a formation mechanism was put forward with emphasis on the chemical and the electrochemical foundations.

  4. Study on plasma assisted metal-organic chemical vapor deposition of Zr,,C,N... and Ti,,C,N... thin films and in situ plasma diagnostics with optical

    E-Print Network [OSTI]

    Boo, Jin-Hyo

    films and in situ plasma diagnostics with optical emission spectroscopy S. J. Cho, S.-H. Nam, C.-K. JungStudy on plasma assisted metal-organic chemical vapor deposition of Zr,,C,N... and Ti,,C,N... thin C,N films were synthesized by pulsed dc plasma assisted metal-organic chemical vapor deposition

  5. JOURNAL DE PHYSIQUE CoZZoque C8, suppZ6ment au n08, Tome 41, aoiit 1980, page C8-745 LOW TEMPERATURE THERMAL PROPERTIES OF AMORPHOUS SUPERCONDUCTING ZrCu

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    TEMPERATURE THERMAL PROPERTIES OF AMORPHOUS SUPERCONDUCTING ZrCu H.v. ~Ehneysen,M. Platte, W. Sander, H- applications - from two major points: (1) the investigation of superconductinq properties yields information the superconductinp transition temperatufe Tc, the condensation of electronic quasiparticles permits access

  6. L e x ica l M o rp h o lo g y a n d th e T w o O rth o g ra p h ic W illia m B a d e c k e r, B re n d a R a p p

    E-Print Network [OSTI]

    Caramazza, Alfonso

    L e x ica l M o rp h o lo g y a n d th e T w o O rth o g ra p h ic R o u tes W illia m B a d e c k e r, B re n d a R a p p Jo h n s H op k ins U n iv ersity , B altim o re, U S A A lfo n so C a ra m a z z a H a rva rd U n iversity, C a m b rid g e, U S A W e r e p o r t a c a s e o f d y s g r a p h

  7. Synchrotron Radiation Photoemission Spectroscopic Study of Band Offsets and Interface Self-cleaning by Atomic Layer Deposited HfO2 on In0.53Ga0.47As and In0.52Al0.48As

    SciTech Connect (OSTI)

    Kobayashi, Masaharu; /SLAC, SSRL; Chen, P.T.; Sun, Y.; Goel, N.; Majhi, P.; Garner, M; Tsai, W.; Pianetta, P.; Nishi, Y.; /SLAC, SSRL

    2008-10-31T23:59:59.000Z

    The Synchrotron Radiation Photoemission Spectroscopic (SRPES) study was conducted to (a) investigate the surface chemistry of In{sub 0.53}Ga{sub 0.47}As and In{sub 0.52}Al{sub 0.48}As post chemical and thermal treatments, (b) construct band diagram and (c) investigate the interface property of HfO{sub 2}/In{sub 0.53}Ga{sub 0.47}As and HfO{sub 2}/In{sub 0.52}Al{sub 0.48}As. Dilute HCl and HF etch remove native oxides on In{sub 0.53}Ga{sub 0.47}As and In{sub 0.52}Al{sub 0.47}As, whereas in-situ vacuum annealing removes surface arsenic pile-up. After the atomic layer deposition of HfO{sub 2}, native oxides were considerably reduced compared to that in as-received epi-layers, strongly suggesting the self-clean mechanism. Valence and conduction band offsets are measured to be 3.37 {+-} 0.1eV, 1.80 {+-} 0.3eV for In{sub 0.53}Ga{sub 0.47}As and 3.00 {+-} 0.1eV, 1.47 {+-} 0.3eV for In{sub 0.52}Al{sub 0.47}As, respectively.

  8. Robocast Pb(Zr{sub 0.95}Ti{sub 0.05})O{sub 3} Ceramic Monoliths and Composites

    SciTech Connect (OSTI)

    TUTTLE,BRUCE A.; SMAY,JAMES E.; CESARANO III,JOSEPH; VOIGT,JAMES A.; SCOFIELD,TIMOTHY W.; OLSON,WALTER R.; LEWIS,J.A.

    2000-07-18T23:59:59.000Z

    Robocasting, a computer controlled slurry deposition technique, was used to fabricate ceramic monoliths and composites of chemically prepared Pb(Zr{sub 0.95}Ti{sub 0.05})O{sub 3} (PZT 95/5) ceramics. Densities and electrical properties of the robocast samples were equivalent to those obtained for cold isostatically pressed (CIP) parts formed at 200 MPa. Robocast composites consisting of alternate layers of the following sintered densities: (93.9%--96.1%--93.9%), were fabricated using different levels of organic pore former additions. Modification from a single to a multiple material deposition robocaster was essential to the fabrication of composites that could withstand repeated cycles of saturated polarization switching under 30 kV/cm fields. Further, these composites withstood 500 MPa hydrostatic pressure induced poled ferroelectric (FE) to antiferroelectric (AFE) phase transformation during which strain differences on the order of 0.8% occurred between composite elements.

  9. Process for production of solution-derived (Pb,La)(Nb,Sn,Zr,Ti)O{sub 3} thin films and powders

    DOE Patents [OSTI]

    Boyle, T.J.

    1999-01-12T23:59:59.000Z

    A simple and rapid process for synthesizing (Pb,La)(Nb,Sn,Zr,Ti)O{sub 3} precursor solutions and subsequent ferroelectric thin films and powders of the perovskite phase of these materials has been developed. This process offers advantages over standard methods, including: rapid solution synthesis (<10 minutes), use of commercially available materials, film production under ambient conditions, ease of lanthanum dissolution at high concentrations, and no heating requirements during solution synthesis. For lanthanum-doped ferroelectric materials, the lanthanum source can be added with total synthesis time less than 10 minutes. Films and powders are crystallized at approximately 650 C and exhibit ferroelectric properties comparable to films and powders produced by other techniques which require higher crystallization temperatures. 2 figs.

  10. Measurement of the two neutrino double beta decay half-life of Zr-96 and search for associated neutrinoless processes with the NEMO-3 detector

    E-Print Network [OSTI]

    Argyriades, J; Augier, C; Baker, J; Barabash, A S; Bongrand, M; Broudin-Bay, G; Brudanin, V B; Caffrey, A J; Chapon, A; Chauveau, E; Daraktchieva, Z; Durand, D; Egorov, V G; Fatemi-Ghomi, N; Flack, R; Freshville, A; Guillon, B; Hubert, Ph; Jullian, S; Kauer, M; King, S; Kochetov, O I; Konovalov, S I; Kovalenko, V E; Lalanne, D; Lang, K; Lemiere, Y; Lutter, G; Mamedov, F; Marquet, Ch; Martín-Albo, J; Mauger, F; Nachab, A; Nasteva, I; Nemchenok, I B; Nova, F; Novella, P; Ohsumi, H; Pahlka, R B; Perrot, F; Piquemal, F; Reyss, J L; Ricol, J S; Saakyan, R; Sarazin, X; Simard, L; Shitov, Yu A; Smolnikov, A A; Snow, S; Söldner-Rembold, S; Stekl, I; Sutton, C S; Szklarz, G; Thomas, J; Timkin, V V; Tretyak, V I; Tretyak, Vl I; Umatov, V I; Vàla, L; Vanyushin, I A; Vasiliev, V A; Vorobel, V; Vylov, Ts

    2009-01-01T23:59:59.000Z

    Using 1221 days of data from the NEMO-3 detector, the measurement of Zr-96 2vbb decay half-life is [2.35 +/- 0.14(stat) +/- 0.19(syst)] x 10^19 yr. Different characteristics of the final state electrons have been studied, such as the energy sum, individual electron energy, and angular distribution. The 2v nuclear matrix element is extracted using the measured 2vbb half-life and is 0.049 +/- 0.003. A 90% CL limit is set on the 0vbb decay half-life of > 9.2 x 10^21 yr corresponding to a limit on the effective Majorana neutrino mass < 7.2 - 19.5 eV. Limits on other mechanisms of 0vbb decay have also been set.

  11. Evidence of Eu{sup 2+} 4f electrons in the valence band spectra of EuTiO{sub 3} and EuZrO{sub 3}

    SciTech Connect (OSTI)

    Kolodiazhnyi, T. [National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); Valant, M. [Materials Research Laboratory, University of Nova Gorica, Vipavska 13, 5000 Nova Gorica (Slovenia); Williams, J. R. [International Center for Young Scientists (ICYS), MANA, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); Bugnet, M.; Botton, G. A. [Department of Materials Science and Engineering, McMaster University, Hamilton, Ontario L8S 4L7 (Canada); Ohashi, N. [International Center for Materials Nanoarchitectonics, MANA, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); Sakka, Y. [National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan)

    2012-10-15T23:59:59.000Z

    We report on optical band gap and valence electronic structure of two Eu{sup 2+}-based perovskites, EuTiO{sub 3} and EuZrO{sub 3} as revealed by diffuse optical scattering, electron energy loss spectroscopy, and valence-band x-ray photoelectron spectroscopy. The data show good agreement with the first-principles studies in which the top of the valence band structure is formed by the narrow Eu 4f{sup 7} electron band. The O 2p band shows the features similar to those of the Ba(Sr)TiO{sub 3} perovskites except that it is shifted to higher binding energies. Appearance of the Eu{sup 2+} 4f{sup 7} band is a reason for narrowing of the optical band gap in the title compounds as compared to their Sr-based analogues.

  12. Comparative studies of optical and elastic properties of ZrO{sub 2} thin films prepared under normal and oblique incidence deposition geometries

    SciTech Connect (OSTI)

    Sarkar, P., E-mail: piyali.sarkar4@gmail.com; Tokas, R. B., E-mail: piyali.sarkar4@gmail.com; Jena, S., E-mail: piyali.sarkar4@gmail.com; Thakur, S., E-mail: piyali.sarkar4@gmail.com; Sahoo, N. K., E-mail: piyali.sarkar4@gmail.com [Atomic and Molecular Physics Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India)

    2014-04-24T23:59:59.000Z

    Oblique angle deposited optical thin films have attracted recent researcher’s interest because of their attractive optical, micro-structural, mechanical properties and more importantly because of their great potential in achieving tunability in refractive index. These properties in turn make it important in case of designing different optical devices. In the present work, ZrO{sub 2} thin films have been deposited on fused silica substrate by electron beam evaporation technique in normal as well as oblique angle deposition configurations. Optical properties, especially refractive index of the films have been estimated by fitting the measured transmission spectra with suitable theoretical dispersion models. Atomic force microscopy has been employed to characterize morphological properties of samples. The elastic properties of both the films are estimated by Atomic Force Acoustic Microscopy, a new and highly sensitive technique for thin films.

  13. Influence of plasma-based in-situ surface cleaning procedures on HfO{sub 2}/In{sub 0.53}Ga{sub 0.47}As gate stack properties

    SciTech Connect (OSTI)

    Chobpattana, Varistha; Mates, Thomas E.; Mitchell, William J.; Zhang, Jack Y.; Stemmer, Susanne [Materials Department, University of California, Santa Barbara, California 93106-5050 (United States)] [Materials Department, University of California, Santa Barbara, California 93106-5050 (United States)

    2013-10-21T23:59:59.000Z

    We report on the influence of variations in the process parameters of an in-situ surface cleaning procedure, consisting of alternating cycles of nitrogen plasma and trimethylaluminum dosing, on the interface trap density of highly scaled HfO{sub 2} gate dielectrics deposited on n-In{sub 0.53}Ga{sub 0.47}As by atomic layer deposition. We discuss the interface chemistry of stacks resulting from the pre-deposition exposure to nitrogen plasma/trimethylaluminum cycles. Measurements of interface trap densities, interface chemistry, and surface morphology show that variations in the cleaning process have a large effect on nucleation and surface coverage, which in turn are crucial for achieving low interface state densities.

  14. Sub-250?nm low-threshold deep-ultraviolet AlGaN-based heterostructure laser employing HfO{sub 2}/SiO{sub 2} dielectric mirrors

    SciTech Connect (OSTI)

    Kao, Tsung-Ting; Liu, Yuh-Shiuan; Mahbub Satter, Md.; Li, Xiao-Hang; Lochner, Zachary; Douglas Yoder, P.; Detchprohm, Theeradetch; Dupuis, Russell D.; Shen, Shyh-Chiang, E-mail: shyh.shen@ece.gatech.edu; Ryou, Jae-Hyun [School of Electrical and Computer Engineering, Georgia Institute of Technology, 777 Atlantic Dr. NW, Atlanta, Georgia 30332-0250 (United States)] [School of Electrical and Computer Engineering, Georgia Institute of Technology, 777 Atlantic Dr. NW, Atlanta, Georgia 30332-0250 (United States); Fischer, Alec M.; Wei, Yong; Xie, Hongen; Ponce, Fernando A. [Department of Physics, Arizona State University, Tempe, Arizona 85287-1504 (United States)] [Department of Physics, Arizona State University, Tempe, Arizona 85287-1504 (United States)

    2013-11-18T23:59:59.000Z

    We report a sub-250-nm, optically pumped, deep-ultraviolet laser using an Al{sub x}Ga{sub 1?x}N-based multi-quantum-well structure grown on a bulk Al-polar c-plane AlN substrate. TE-polarization-dominant lasing action was observed at room temperature with a threshold pumping power density of 250?kW/cm{sup 2}. After employing high-reflectivity SiO{sub 2}/HfO{sub 2} dielectric mirrors on both facets, the threshold pumping power density was further reduced to 180?kW/cm{sup 2}. The internal loss and threshold modal gain can be calculated as 2?cm{sup ?1} and 10.9?cm{sup ?1}, respectively.

  15. Effect of synthesis conditions on the nanopowder properties of Ce{sub 0.9}Zr{sub 0.1}O{sub 2}

    SciTech Connect (OSTI)

    Zimicz, M.G.; Fabregas, I.O.; Lamas, D.G. [CINSO (Centro de Investigaciones en Solidos) CONICET-CITEFA J.B. de La Salle 4397, 1603 Villa Martelli, Pcia. de Buenos Aires (Argentina)] [CINSO (Centro de Investigaciones en Solidos) CONICET-CITEFA J.B. de La Salle 4397, 1603 Villa Martelli, Pcia. de Buenos Aires (Argentina); Larrondo, S.A., E-mail: susana@di.fcen.uba.ar [Laboratorio de Procesos Cataliticos, Departamento de Ingenieria Quimica, Facultad de Ingenieria, Universidad de Buenos Aires, Pabellon de Industrias, Ciudad Universitaria, 1428 Buenos Aires (Argentina)

    2011-06-15T23:59:59.000Z

    Graphical abstract: . The synthesis of nanocrystalline Ce{sub 0.9}Zr{sub 0.1}O{sub 2} powders via the gel-combustion method, using different fuels, and following either stoichiometric or non-stoichiometric pH-controlled routes is investigated. Research highlights: {yields} All samples exhibited the fluorite-type crystal structure, nanometric average crystallite size and negligible carbon content. {yields} Synthesis conditions strongly affect the average crystallite size, the degree of agglomeration, the specific surface area and the pore volume. {yields} Our results indicate that, by controlling the synthesis conditions it is possible to obtain solids with custom-made morphological properties. -- Abstract: In this work, the synthesis of nanocrystalline Ce{sub 0.9}Zr{sub 0.1}O{sub 2} powders via the gel-combustion method, using different fuels, and following either stoichiometric or non-stoichiometric pH-controlled routes is investigated. The objective is to evaluate the effect of synthesis conditions on the textural and morphological properties, and the crystal structure of the synthesized materials. The solids were characterized by nitrogen physisorption, Scanning Electron Microscopy (SEM), X-ray powder diffraction (XPD), and Carbon-Hydrogen-Nitrogen Elemental Analysis (CHN). All the powders exhibited nanometric crystallite size, fluorite-type structure and negligible carbon content. Synthesis conditions strongly affect the average crystallite size, the degree of agglomeration, the specific surface area and the pore volume. Our results indicate that, by controlling the synthesis conditions it is possible to obtain solids with custom-made morphological properties.

  16. Influence of doping (Ti, V, Zr, W) and annealing on the sp{sup 2} carbon structure of amorphous carbon films

    SciTech Connect (OSTI)

    Adelhelm, C.; Balden, M. [Max-Planck-Institut fuer Plasmaphysik, Materials Research, EURATOM Association, Boltzmannstrasse 2, D-85748 Garching (Germany); Rinke, M.; Stueber, M. [Forschungszentrum Karlsruhe, Institute of Materials Research I, Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen (Germany)

    2009-02-01T23:59:59.000Z

    The influence of the transition metal (Ti, V, Zr, W) doping on the carbon matrix nanostructuring during the thin film growth and subsequent annealing is investigated. Pure and metal-doped amorphous carbon films (a-C, a-C:Me) were deposited at room temperature by nonreactive magnetron sputtering. The carbon structure of as-deposited and postannealed (up to 1300 K) samples was analyzed by x-ray diffraction (XRD) and Raman spectroscopy. The existence of graphenelike regions in a-C is concluded from a (10) diffraction peak. A comparison of the XRD and Raman results suggests that XRD probes only the small amount of 2-3 nm large graphenelike regions, whereas the majority of the sp{sup 2} phase is present in smaller distorted aromatic clusters which are probed only by Raman spectroscopy. Annealing leads to an increase in the graphene size and the aromatic cluster size. During the carbon film growth the addition of metals enhances ordering of sp{sup 2} carbon in sixfold aromatic clusters compared to a-C; Ti, and Zr showing the strongest effect, W the lowest. This order qualitatively corresponds with the catalytic activity of the respective carbides found during graphitization of carbide-doped graphites published in the literature. With annealing, carbide crystallite formation and growth occurs in a-C:Me films, which destroys the initial carbon structure, reduces the size of the initially formed aromatic clusters and the differences in carbon structure introduced by different dopants. For high annealing temperatures the carbon structure of a-C:Me films is similar to that of a-C, and is determined only by the annealing temperature.

  17. Enhancement in the transport critical current density J{sub c} in YBa{sub 2}Cu{sub 3}O{sub 7??} added with an insulating nano crystalline YBa{sub 2}HfO{sub 5.5} perovskite

    SciTech Connect (OSTI)

    Rejith, P. P.; Vidya, S.; Thomas, J. K. [Electronic Materials Research Laboratory, Department of Physics, Mar Ivanios College, Thiruvananthapuram- 695 015, Kerala (India); Solomon, Sam [Department of Physics, St. John's College, Anchal-691306, Kerala (India)

    2014-01-28T23:59:59.000Z

    When a magnetic field is applied to type II superconductors, such as YBa{sub 2}Cu{sub 3}0{sub 7??} (YBCO), the flux quanta penetrate the material as a regular array of vortices. However when transport currents are applied, they act to move these vortices, thus lowers the critical current density (J{sub c}) as well as destroying superconductivity. The development of microstructures made of YBCO materials has enabled engineers to increase the critical current density, within Type II materials by introducing flux pinning centres into the material. The microstructure and flux pinning properties of YBa{sub 2}Cu{sub 3}O{sub 7??} system with varying levels (0-5 wt. %) of a nano perovskite ceramic insulator; YBa{sub 2}HfO{sub 5.5} addition was studied in detail. Orthorhombic YBa{sub 2}Cu{sub 3}O{sub 7??} powder was prepared through conventional solid state route and a modified combustion method was used for synthesizing nanocrystalline YBa{sub 2}HfO{sub 5.5}. The structure and microstructure of the samples examined by X-ray diffraction and scanning electron microscopy showed that YBa{sub 2}HfO{sub 5.5} and YBCO remained unreacted even at higher processing temperature without deteriorating the superconducting properties. The scanning electron microscope image shows that YBa{sub 2}HfO{sub 5.5} forms an electrical-network between grains. These observations suggest that the YBa{sub 2}HfO{sub 5.5} addition to the Y-123-compounds improve the electrical connection between superconducting grains and substantial improvements in the relative electrical transport properties of the composites. The variation of sintering temperature, density, critical transition temperature (T{sub c}) and magnetic field dependence of critical current density (J{sub c}) of YBa{sub 2}Cu{sub 3}O{sub 7??} having different proportions of YBa{sub 2}HfO{sub 5.5} in the matrix were also studied in detail. It is found that the addition of these elements considerably enhances the flux pinning strength of the system, and there is also an increase of critical temperature (T{sub c}) and critical current density (J{sub c}) up to an optimum value of 8.76 × 10{sup 4} A/cm{sup 2} for a concentration of 2 wt % addition of nano YBa{sub 2}HfO{sub 5.5}. The enhancement of the critical current density in the YBa{sub 2}Cu{sub 3}O{sub 7??} - YBa{sub 2}HfO{sub 5.5} samples is attributed to the sustained formation of the insulating and non-reacting YBa{sub 2}HfO{sub 5.5} phase acting as pinning center. The addition of YBa{sub 2}HfO{sub 5.5} in YBa{sub 2}Cu{sub 3}O{sub 7??} bulk superconductor also enhances the pinning force density from 3 ×10{sup 6} N/m{sup 3} to 69.6 × 10{sup 6}N/m{sup 3} at 77 K.

  18. Oak Ridge Reservation Volume 3. Records relating to RaLa, iodine-131, and cesium-137 at the Oak Ridge National Laboratory and the Oak Ridge Operations Office: A guide to record series of the Department of Energy and its contractors

    SciTech Connect (OSTI)

    NONE

    1995-03-21T23:59:59.000Z

    The purpose of this guide is to describe each of the documents and record series pertaining to the production, release, and disposal of radioactive barium-lanthanum (RaLa), iodine-131, and cesium-137 at the Department of Energy`s (DOE) Oak Ridge National Laboratory (ORNL) in Oak Ridge, Tennessee. History Associates Incorporated (HAI) prepared this guide as part of DOE`s Epidemiologic Records Inventory Project, which seeks to verify and conduct inventories of epidemiologic and health-related records at various DOE and DOE contractor sites. This introduction briefly describes the Epidemiologic Records Inventory Project and HAI`s role. It provides information on the history of the DOE-Oak Ridge Reservation (ORR), particularly ORNL. Specific attention is given to the production of RaLa and the fission products iodine-131 and cesium-137. This introduction also describes the methodologies HAI used in the selection and inventorying of documents and record series pertaining to RaLa, iodine-131, and cesium-137, and in the production of this guide. Concluding paragraphs describe the arrangement of the record series, explain the information contained in the record series descriptions, and indicate restrictions on access to the records.

  19. Low interfacial trap density and sub-nm equivalent oxide thickness in In{sub 0.53}Ga{sub 0.47}As (001) metal-oxide-semiconductor devices using molecular beam deposited HfO{sub 2}/Al{sub 2}O{sub 3} as gate dielectrics

    SciTech Connect (OSTI)

    Chu, L. K. [Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Katholieke Universiteit Leuven, 3001 Leuven (Belgium); Merckling, C.; Dekoster, J.; Caymax, M. [Interuniversity Microelectronics Center (IMEC vzw), 3001 Leuven (Belgium); Alian, A.; Heyns, M. [Katholieke Universiteit Leuven, 3001 Leuven (Belgium); Interuniversity Microelectronics Center (IMEC vzw), 3001 Leuven (Belgium); Kwo, J. [Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Center for Condensed Matter Sciences, National Taiwan University, Taipei 10617, Taiwan (China); Hong, M. [Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan (China)

    2011-07-25T23:59:59.000Z

    We investigated the passivation of In{sub 0.53}Ga{sub 0.47}As (001) surface by molecular beam epitaxy techniques. After growth of strained In{sub 0.53}Ga{sub 0.47}As on InP (001) substrate, HfO{sub 2}/Al{sub 2}O{sub 3} high-{kappa} oxide stacks have been deposited in-situ after surface reconstruction engineering. Excellent capacitance-voltage characteristics have been demonstrated along with low gate leakage currents. The interfacial density of states (D{sub it}) of the Al{sub 2}O{sub 3}/In{sub 0.53}Ga{sub 0.47}As interface have been revealed by conductance measurement, indicating a downward D{sub it} profile from the energy close to the valence band (medium 10{sup 12} cm{sup -2}eV{sup -1}) towards that close to the conduction band (10{sup 11} cm{sup -2}eV{sup -1}). The low D{sub it}'s are in good agreement with the high Fermi-level movement efficiency of greater than 80%. Moreover, excellent scalability of the HfO{sub 2} has been demonstrated as evidenced by the good dependence of capacitance oxide thickness on the HfO{sub 2} thickness (dielectric constant of HfO{sub 2}{approx}20) and the remained low D{sub it}'s due to the thin Al{sub 2}O{sub 3} passivation layer. The sample with HfO{sub 2} (3.4 nm)/Al{sub 2}O{sub 3} (1.2 nm) as the gate dielectrics has exhibited an equivalent oxide thickness of {approx}0.93 nm.

  20. CERN/FC/5469/RA Original: English

    E-Print Network [OSTI]

    for the CERN Site supervision (SUSI) Supply of power cables for the high voltage electrical network-based video surveillance cameras from multiple manufacturers. Supply of power cables for the renovation of the electrical power distribution network. Several types of power cable are requested for a total quantity of 78

  1. Rainfall Manipulation Plot Study (RaMPS)

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Blair, John (Kansas State University); Fay, Phillip (USDA-ARS); Knapp, Alan (Colorado State University); Collins, Scott (University of New Mexico); Smith, Melinda (Yale University)

    Data sets are available as ASCII files, in Excel spreadsheets, and in SAS format. (Taken from http://www.konza.ksu.edu/ramps/backgrnd.html

  2. OAS-RA-12-14

    Broader source: Energy.gov (indexed) [DOE]

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary) "ofEarly Careerlumens_placard-green.epsEnergy Second Quarter4,(National Renewable Energy Laboratory)

  3. Microsoft Word - RA6120_2.doc

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsrucLas Conchas recovery challenge fundProject8 -3 Subject: TankINL busing TO:1CBFO QAPD Rev.

  4. Effect of ZrO{sub 2}-doping of nanosized Fe{sub 2}O{sub 3}/MgO system on its structural, surface and catalytic properties

    SciTech Connect (OSTI)

    Hassan, Neveen A. [National Research Center, Dokki, Cairo (Egypt)] [National Research Center, Dokki, Cairo (Egypt); El-Molla, Sahar A., E-mail: saharelmolla@yahoo.com [Chemistry Department, Faculty of Education, Ain Shams University, Roxy 11757, Cairo (Egypt); Mohamed, Ghada M.; Fagal, Gehan A. [National Research Center, Dokki, Cairo (Egypt)] [National Research Center, Dokki, Cairo (Egypt)

    2012-09-15T23:59:59.000Z

    Highlights: ? Preparation and characterization nano-sized ZrO{sub 2}-doped Fe{sub 2}O{sub 3}/MgO system. ? Pure and doped solids calcined at 500 and 700 °C are mesoporous adsorbents. ? ZrO{sub 2}-doping increased the lattice constant “a” of MgO lattice to an extent proportional to the amount of ZrO{sub 2} added. ? The catalytic activity in H{sub 2}O{sub 2} decomposition was found to increase as a function of dopant concentration. -- Abstract: Fe{sub 2}O{sub 3}/MgO system was prepared by wet impregnation method followed by treatment with different amounts of Zr-dopant salt then heating at 500 and 700 °C. The dopant concentrations were 0.48, 0.95 and 1.4 mol% ZrO{sub 2}. Pure and variously doped solids were characterized using XRD, N{sub 2}-adsorption isotherms carried out at ?196 °C and catalytic decomposition of H{sub 2}O{sub 2} in aqueous solution at 25–35 °C. The results revealed that the nanosized MgO phase was only detected in the diffractograms of pure and doped solids calcined at 500 °C. Heating pure and doped solids at 700 °C produced nanosized MgFe{sub 2}O{sub 4} phase together with MgO phase. Pure and ZrO{sub 2}-doped solids calcined at 500 and 700 °C are mesoporous adsorbents. The doping process brought about a measurable decrease in the S{sub BET} of Fe{sub 2}O{sub 3}/MgO system with subsequent increase in its catalytic activity. The catalytic activity of the investigated system toward H{sub 2}O{sub 2} decomposition, expressed as reaction rate constant per unit surface area was found to increase as a function of dopant concentration. The maximum increase in the reaction rate constant per unit surface area measured for the reaction carried out at 30 °C attained 125% for the heavily doped samples. This significant increase was based on the catalytic activity of pure catalyst sample measured under the same conditions.

  5. E-Print Network 3.0 - analysis reveal damage Sample Search Results

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    technique... , Germany Abstract: Laser damage thresholds at 248nm of TiO,, ZrO, and HfO, thin films of h optical... thickness on SQ1 quartz glass substrates are determined by...

  6. Description of isoscalar giant dipole resonance in nuclei

    E-Print Network [OSTI]

    Pochivalov, Oleksiy Grigorievich

    2009-05-15T23:59:59.000Z

    Applicability of the Hartree-Fock (HF) based random phase approximation (RPA) with several Skyrme effective interactions to the description of the isoscalar giant monopole (ISGMR) and the isoscalar giant dipole resonance (ISGDR) in 90Zr, 116Sn, 144...

  7. Analysis of the Younger Dryas Impact Layer

    E-Print Network [OSTI]

    Firestone, Richard B.

    2011-01-01T23:59:59.000Z

    in potassium (K), rare-earth elements (REE), phosphorus (P),charcoal, iridium, and rare earth elements peak beneath theBr, Sr, Y, Zr, Ba, rare earth elements (REE), Hf, Ta, Th,

  8. August 2000 Z .Materials Letters 45 2000 128132

    E-Print Network [OSTI]

    Zheng, Yufeng

    . TiNiHf alloys exhibit better shape memory properties than other TiNiX Z .XsPt, Pd, Au, Zr and Ni­132 129 Fig. 1. Schematic illustration for the SME measurement in the bending test. electrode

  9. E-Print Network 3.0 - alloy sheets produced Sample Search Results

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    tantalum-base alloys (e... .g. Ta-8W-2Hf), niobium alloys (Nb-1Zr), and molybdenum and tungsten alloys. The results are compared... operating temperature window for structural...

  10. E-Print Network 3.0 - alloys sheet processed Sample Search Results

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    tantalum-base alloys (e... .g. Ta-8W-2Hf), niobium alloys (Nb-1Zr), and molybdenum and tungsten alloys. The results are compared... operating temperature window for structural...

  11. E-Print Network 3.0 - alloy satellite boxes Sample Search Results

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    tantalum-base alloys (e... .g. Ta-8W-2Hf), niobium alloys (Nb-1Zr), and molybdenum and tungsten ... Source: California at Los Angeles, University of - School of Engineering...

  12. Salt-assistant combustion synthesis of nanocrystalline Nd{sub 2}(Zr{sub 1-x}Sn{sub x}){sub 2}O{sub 7} (0 {<=} x {<=} 1) solid solutions

    SciTech Connect (OSTI)

    Tong Yuping, E-mail: huabeitong@yahoo.cn [School of Civil Engineering and Communication, North China Institute of Water Conservancy and Hydroelectric Power, Zhengzhou 450011 (China); Wang Yanping [College of Mechanical Engineering and Automation, Zhejiang Sci-Tech University, Hangzhou 310018 (China)

    2009-11-15T23:59:59.000Z

    Nanocrystalline Nd{sub 2}(Zr{sub 1-x}Sn{sub x}){sub 2}O{sub 7} series solid solutions were prepared by a convenient salt-assisted combustion process using glycine as fuel. The samples were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, Raman spectroscopy, transmission electron microscopy and high-resolution transmission electron microscopy. The results showed the Zr ion can be partially replaced by Sn ion. The partial substituted products were still single-phase solid solutions and the crystal form remained unchanged. TEM images reveal that the products are composed of well-dispersed square-shaped nanocrystals. The method provides a convenient and low-cost route for the synthesis of nanostructures of oxide materials.

  13. Cation ordering transformations in Ba(Mg{sub 1/3}Ta{sub 2/3})O{sub 3}-BaZrO{sub 3} perovskite solid solutions

    SciTech Connect (OSTI)

    Chai, L.; Akbas, M.A.; Davies, P.K. [Univ. of Pennsylvania, Philadelphia, PA (United States). Dept. of Materials Science and Engineering] [Univ. of Pennsylvania, Philadelphia, PA (United States). Dept. of Materials Science and Engineering; Parise, J.B. [Univ. of New York, Stony Brook, NY (United States). Dept. of Earth and Space Sciences] [Univ. of New York, Stony Brook, NY (United States). Dept. of Earth and Space Sciences

    1997-09-01T23:59:59.000Z

    The effect of the substitution of BaZrO{sub 3} on the cation ordering in Ba(Mg{sub 1/3}Ta{sub 2/3})O{sub 3} was studied using TEM and X-ray and neutron diffraction. Almost no solubility of Zr was found in the 1:2 ordered, trigonal structure of the Ba(Mg{sub 1/3}Ta{sub 2/3})O{sub 3} end-member (P{bar 3}m1), and a transformation to a 1:1 ordered, cubic (Fm{bar 3}m) phase with a = 2a{sub per} occurs for substitution levels between {approximately}10 and 25 mol% BaZrO{sub 3}. The structure of this Ba({beta}{prime}{sub 1/2}{beta}{double_prime}{sub 1/2})O{sub 3}-type phase consists of two distinct octahedral sites, {beta}{prime} and {beta}{double_prime}. The occupancies of the two cation positions, refined using the Rietveld method, were found to be consistent with a random site model in which {beta}{double_prime} is occupied by Ta, and {beta}{prime} by a random distribution of the remaining cations. The homogeneity range of the 1:1 solid solutions predicted by this model, Ba{l_brace}[Mg{sub (2{minus}y)/3} Ta{sub (1{minus}2y)/3} Zr{sub y}]{sub 1/2}[Ta]{sub 1/2}{r_brace}O{sub 3} (0.0 < y {le} 0.5), is in excellent agreement with that observed experimentally.

  14. A-site deficient perovskites in the SrO-ZrO{sub 2}-Nb{sub 2}O{sub 5} system: Composition dependent structures from neutron powder diffraction data

    SciTech Connect (OSTI)

    Schmid, Siegbert, E-mail: S.Schmid@chem.usyd.edu.au [School of Chemistry, University of Sydney, Sydney NSW 2006 (Australia); Withers, Ray L. [Research School of Chemistry, Australian National University, Canberra ACT 0200 (Australia)

    2012-07-15T23:59:59.000Z

    A series of A-site deficient perovskite-type phases was synthesised and characterised in the SrO-ZrO{sub 2}-Nb{sub 2}O{sub 5} system. The composition range was established as Sr{sub 0.70+x}Zr{sub 0.40+2x}Nb{sub 0.60-2x}O{sub 3}, {approx}0.02{<=}x{<=}0.30, and the resulting structures refined using high resolution neutron powder diffraction data. While structures in this composition range are closely related to the cubic perovskite parent, the symmetry for all investigated compositions is lowered to tetragonal or orthorhombic. For x<0.15 the resulting space group is tetragonal I4/mcm, for x>0.15 it is orthorhombic Pnma and for x=0.15 two phases co-exist, in space groups I4/mcm and Pnma. - Graphical abstract: Structured diffuse intensity indicating additional short range order in the defect perovskite Sr{sub 0.72}Zr{sub 0.44}Nb{sub 0.56}O{sub 3}. Highlights: Black-Right-Pointing-Pointer A-site deficient perovskites synthesised in Sr{sub 0.70+x}Zr{sub 0.40+2x}Nb{sub 0.60-2x}O{sub 3}, {approx}0.02 {<=}x{<=}0.30. Black-Right-Pointing-Pointer Space groups established from X-ray, electron and neutron powder diffraction. Black-Right-Pointing-Pointer Structures refined and phase transition established from neutron diffraction data.

  15. FTIR study of hydrogen and carbon monoxide adsorption on Pt/TiO{sub 2}, Pt/ZrO{sub 2}, and Pt/Al{sub 2}O{sub 3}

    SciTech Connect (OSTI)

    Benvenutti, E.V.; Franken, L.; Moro, C.C.; Davanzo, C.U.

    1999-11-09T23:59:59.000Z

    The Pt/TiO{sub 2}, Pt/ZrO{sub 2}, and Pt/Al{sub 2}O{sub 3} catalysts submitted to low-temperature reduction (LTR,200 C) and high-temperature reduction (HTR, 500 C) and exposed to hydrogen and carbon monoxide at room temperature were studied by infrared spectroscopy. There is a strong loss of transmission in the entire infrared spectra on Pt/TiO{sub 2} after its exposure to hydrogen, which is related to the reducibility of the support. A typical SMSI behavior (strong metal-support interaction), such as the decrease in carbon monoxide adsorption capacity, was detected on Pt/TiO{sub 2} and Pt/ZrO{sub 2} after exposure to hydrogen, even for the catalysts submitted to LTR treatment. Also a carbonyl band shift to lower wavenumber was observed on LTR-treated Pt/TiO{sub 2}, Pt/ZrO{sub 2}, and Pt/Al{sub 2}O{sub 3} after exposure to hydrogen. The authors interpreted this SMSI behavior as an electronic rather than morphological effect, which was induced by the presence of hydrogen spillover.

  16. Formation and characterization of microstructure of as-cast Mg–6Gd–4Y–xZn–0.5Zr (x = 0.3, 0.5 and 0.7 wt.%) alloys

    SciTech Connect (OSTI)

    Wu, Y.J. [National Engineering Research Center of Light Alloy Net Forming, Shanghai Jiao Tong University, Shanghai 200240 (China); State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai 200240 (China); Xu, C. [National Engineering Research Center of Light Alloy Net Forming, Shanghai Jiao Tong University, Shanghai 200240 (China); Zheng, F.Y. [National Engineering Research Center of Light Alloy Net Forming, Shanghai Jiao Tong University, Shanghai 200240 (China); State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai 200240 (China); Peng, L.M., E-mail: plm616@sjtu.edu.cn [National Engineering Research Center of Light Alloy Net Forming, Shanghai Jiao Tong University, Shanghai 200240 (China); State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai 200240 (China); Zhang, Y.; Ding, W.J. [National Engineering Research Center of Light Alloy Net Forming, Shanghai Jiao Tong University, Shanghai 200240 (China); State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai 200240 (China)

    2013-05-15T23:59:59.000Z

    Mg–6Gd–4Y–xZn–0.5Zr (x = 0.3, 0.5 and 0.7 wt.%) alloys were prepared via conventional ingot metallurgy (I/M) in this study. The as-cast microstructures of these alloys were established by X-ray diffraction (XRD) analyses, optical microscope (OM), scanning electron microscope (SEM) and transmission electron microscope (TEM) observations. Lamellar stacking order (SF) and 14H-type long period stacking order (LPSO) structure within ?-Mg matrix are formed in the three as-cast alloys. The eutectic secondary phase is (Mg,Zn){sub 24}(Gd,Y){sub 5} for the alloy containing 0.3 wt.% Zn, while, it is (Mg,Zn){sub 3}(Gd,Y) for the alloys containing 0.5 wt.% Zn and 0.7 wt.% Zn. Moreover, X phase-(Mg,Zn){sub 12}(Gd,Y) is formed in the latter two as-cast alloys. - Highlights: • LPSO structure has first been found in as-cast Mg–6Gd–4Y–xZn–0.5Zr. • X-phase exists in as-cast Mg–6Gd–4Y–0.3(0.5)Zn–0.5Zr. • Zn content results in different ?-phase in the studied alloys.

  17. Lasing characteristics of ZrO{sub 2}–Y{sub 2}O{sub 3}–Ho{sub 2}O{sub 3} crystal

    SciTech Connect (OSTI)

    Borik, M A; Lomonova, E E; Kulebyakin, A V; Ushakov, S N [A M Prokhorov General Physics Institute, Russian Academy of Sciences, Moscow (Russian Federation); Lyapin, A A; Ryabochkina, P A; Chabushkin, A N [N.P. Ogarev Mordovian State University, Saransk (Russian Federation)

    2013-09-30T23:59:59.000Z

    The spectral dependences of the gain cross section of the {sup 5}I{sub 8} ? {sup 5}I{sub 7}, {sup 5}I{sub 7} ? {sup 5}I{sub 8} transition of Ho{sup 3+} ions in the ZrO{sub 2} – 13.6 mol % Y{sub 2}O{sub 3} – 0.4 mol % Ho{sub 2}O{sub 3} crystal are calculated at different relative population inversions using the absorption and luminescence spectra of the {sup 5}I{sub 8} ? {sup 5}I{sub 7} and {sup 5}I{sub 7} ? {sup 5}I{sub 8} transitions of Ho{sup 3+} ions at T=''300'' K. Lasing of these crystals at the {sup 5}I{sub 7} ? {sup 5}I{sub 8} transition is obtained for the first time under pumping by a Tm : YLiF{sub 4} laser (?{sub p} = 1.905 ?m). The lasing wavelength is 2.17 ?m. (lasers)

  18. Negative void reactivity in a large liquid-metal fast breeder reactor with hydrogenous moderator (ZrH[sub 1. 7]) layers

    SciTech Connect (OSTI)

    Oka, Yoshiaki; Jevremovic, T.; Koshizuka, Seiichi (Univ. of Tokyo, Ibaraki (Japan). Nuclear Engineering Research Lab.)

    1994-07-01T23:59:59.000Z

    Placing a thin hydrogenous moderator (ZrH[sub 1.7]) layer between the seed and the blanket is very effective in reducing the sodium void reactivity of a liquid-metal fast breeder reactor (LMFBR). The void reactivity reduction is attributed to the decrease in neutron production and increase in neutron absorption in the blanket at voiding due to the slowing down of fast neutrons in the layer. This dominates the whole core neutron balance. The fixed hydrogenous layer concept is much more effective than the conventional uniform introduction of such moderator in a core. Furthermore, it does not seriously deteriorate the breeding capability. For realizing the negative sodium void reactivity in a large-sized core, the seeds should be divided by blankets with the layers. The conceptual design of a nonflat LMFBR core is presented for demonstrating the effectiveness of the layer. Negative void reactivity is realized in a radially heterogeneous core of 1,000-MW(electric) class output. The active core is 2.9 m high. It is much taller than the conventional LMFBR core, which is [approximately]1 m high. A wide pitch-to-fuel diameter ratio was chosen so as not to increase the pressure drop in the core. The compound system doubling time is 12.5 yr.

  19. EFFECTS OF ION IRRADIATION ON Zr52.5Cu17.9Ni14.6Al10Ti5 (BAM-11) BULK METALLIC GLASS

    SciTech Connect (OSTI)

    Perez-Bergquist, Alex G [ORNL] [ORNL; Bei, Hongbin [ORNL] [ORNL; Leonard, Keith J [ORNL] [ORNL; Zhang, Yanwen [ORNL] [ORNL; Zinkle, Steven J [ORNL] [ORNL

    2014-01-01T23:59:59.000Z

    Bulk metallic glasses are intriguing candidates for nuclear applications due to their inherent amorphous structure, but their radiation response is largely unknown due to the relatively recent nature of innovations in bulk metallic glass fabrication. Here, microstructural and mechanical property evaluations have been performed on a Zr52.5Cu17.9Ni14.6Al10Ti5 bulk metallic glass (BAM-11) irradiated with 3 MeV Ni+ ions to 0.1 and 1.0 dpa at room temperature and 200 C. Nanoindentation hardness and Young s modulus both decreased by 6 to 20% in samples irradiated at room temperature, with the sample irradiated to 1.0 dpa experiencing the greatest change in mechanical properties. However, no significant changes in properties were observed in the samples irradiated at 200 C, and transmission electron microscopy showed no visible evidence of radiation damage or crystallization following ion irradiation at any of the tested conditions. These results suggest that BAM-11 bulk metallic glass may be useful for certain applications in nuclear environments.

  20. Suppression of Ge-O And Ge-N Bonding at Ge-HfO(2) And Ge-TiO(2) Interfaces By Deposition Onto Plasma-Nitrided Passivated Ge Substrates: Integration Issues Ge Gate Stacks Into Advanced Devices

    SciTech Connect (OSTI)

    Lee, S.; Long, J.P.; Lucovsky, G.; Whitten, J.; Seo, H.; Luning, J.

    2009-05-19T23:59:59.000Z

    A study of changes in nano-scale morphology of thin films of nano-crystalline transition metal (TM) elemental oxides, HfO{sub 2} and TiO{sub 2}, on plasma-nitrided Ge(100) substrates, and Si(100) substrates with ultra-thin (-0.8 nm) plasma-nitrided Si suboxide, SiO{sub x}, x < 2, or SiON interfacial layers is presented. Near edge X-ray absorption spectroscopy (NEXAS) has been used to determine nano-scale morphology of these films by Jahn-Teller distortion removal of band edge d-state degeneracies. These results identify a new and novel application for NEXAS based on the resonant character of the respective O K{sub 1} and N K{sub 1} edge absorptions. This paper also includes a brief discussion of the integration issues for the introduction of this Ge breakthrough into advanced semiconductor circuits and systems. This includes a comparison of nano-crystalline and non-crystalline dielectrics, as well as issues relative to metal gates.

  1. The Nature of the Low Energy Isovector Dipole Excitations in Nuclei

    E-Print Network [OSTI]

    Nica, Emilian

    2011-08-04T23:59:59.000Z

    -consistency and a large smearing parameter. To avoid any sources of error we carried out a self-consistent HF-Continuum RPA (HF-CRPA) to determine the IVGDR response function in 60Ca, 28O and 80Zr. We have also examined the free p-h response in the continuum...

  2. First-principles study of native point defects in hafnia and zirconia J. X. Zheng,1

    E-Print Network [OSTI]

    Ceder, Gerbrand

    117576 2Department of Materials Science and Engineering, Massachusetts Institute of Technology, 77 oxygen chemical potentials and Fermi levels. Oxygen vacancies and oxygen interstitials in both HfO2 and ZrO2 show negative-U behavior. It is shown that HfO2 is less prone to the formation of oxygen point

  3. The Effect of Oxygen Contamination on the Amorphous Structure of Thermally Sprayed Coatings of Cu47Ti33Zr11Ni8Si1

    SciTech Connect (OSTI)

    Matthew Frank Besser

    2002-05-27T23:59:59.000Z

    this research has shown that it is possible to deposit coatings of gas atomized Cu{sub 47}Ti{sub 33}Zr{sub 11}Ni{sub 8}Si{sub 1} powders containing various levels of oxygen contamination using plasma arc spray methods. The structure of the coating was found to depend primarily on the spray environment, with an argon atmosphere producing the most amorphous samples for a given starting powder. The oxygen content of the coatings reflected the relative levels of the oxygen contamination in the starting powders. The analysis of the starting powders displayed oxygen contents ranging from 0.125-0.79 wt.%. It was shown that higher oxygen levels lead to more crystalline structure in the starting powders as determined by X-ray diffraction (XRD) and differential scanning calorimetry (DSC). This trend was found to be true for both the starting powders and for the plasma sprayed coatings. Chemical composition for all starting powders was very close to the nominal alloy composition. Chemical changes in the coatings involved the loss of Cu in coatings where high levels of oxidation were found. Cavitation erosion testing of selected coatings showed a weak trend that coatings prepared by vacuum plasma spray (VPS) had lower damage rates, but there was no clear data to indicate which coating parameters were superior. The range of data produced from testing duplicate coating was too wide to provide a good statistical measure of cavitation erosion resistance. of interest was the fact that when coatings began to show damage from cracking, all samples of a group showed similar damage and usually the damage pattern was somewhat unique to that group of samples. Failure of the coatings was due to features inherent to plasma arc spray (PAS) coating (i.e., pores, splat boundaries, oxide inclusions) rather than the mechanical characteristics of the amorphous alloy.

  4. Dynamic response of Cu4Zr54 metallic glass to high strain rate shock loading: plasticity, spall and atomic-level structures

    SciTech Connect (OSTI)

    Luo, Shengnian [Los Alamos National Laboratory; Arman, Bedri [Los Alamos National Laboratory; Germann, Timothy C [Los Alamos National Laboratory; Cagin, Tahir [TEXAS A& M UNIV

    2009-01-01T23:59:59.000Z

    We investigate dynamic response of Cu{sub 46}Zr{sub 54} metallic glass under adiabatic planar shock wave loading (one-dimensional strain) wjth molecular dynamics simulations, including Hugoniot (shock) states, shock-induced plasticity and spallation. The Hugoniot states are obtained up to 60 CPa along with the von Mises shear flow strengths, and the dynamic spall strength, at different strain rates and temperatures. The spall strengths likely represent the limiting values achievable in experiments such as laser ablation. For the steady shock states, a clear elastic-plastic transition is identified (e.g., in the shock velocity-particle velocity curve), and the shear strength shows strain-softening. However, the elastic-plastic transition across the shock front displays transient stress overshoot (hardening) above the Hugoniot elastic limit followed by a relatively sluggish relaxation to the steady shock state, and the plastic shock front steepens with increasing shock strength. The local von Mises shear strain analysis is used to characterize local deformation, and the Voronoi tessellation analysis, the corresponding short-range structures at various stages of shock, release, tension and spallation. The plasticity in this glass is manifested as localized shear transformation zones and of local structure rather than thermal origin, and void nucleation occurs preferentially at the highly shear-deformed regions. The Voronoi and shear strain analyses show that the atoms with different local structures are of different shear resistances that lead to shear localization (e.g., the atoms indexed with (0,0,12,0) are most shear-resistant, and those with (0,2,8,1) are highly prone to shear flow). The dynamic changes in local structures are consistent with the observed deformation dynamics.

  5. Application feasibility of Pb(Zr,Ti)O{sub 3} ceramics fabricated from sol-gel derived powders using titanium and zirconium alkoxides

    SciTech Connect (OSTI)

    Huang, C.L.; Chen, B.H.; Wu, L

    2004-04-02T23:59:59.000Z

    It is believed that what may be termed the 'Nanoscaled Century' will lead to a new industrial revolution, particularly in terms of sol-gel methods of assembly for nanostructure devices. A propyl alcohol (1-Pro) based sol-gel chemical has been developed to replace 2-methoxyethanol (MOE), 1,1,1-tris(hydroxymethyl)ethane (THOME) for the fabrication of PbZr{sub 0.53}Ti{sub 0.47}O{sub 3} (PZT) piezoelectric ceramics. This chemical is prepared from sol-gel derived powders that are near to the morphotropic phase boundary (MPB). The pyrochlore phase was still apparent when calcining at 900 deg. C with a shorter calcining time, such as 30 min. However, it disappeared for longer calcining times, for example 3 h or more. From the results of the analysis, PZT ceramics calcinations at 900 deg. C for 4 h, and sintering at 1100 deg. C for 2 h could reach a pyrochlore-free crystal phase with relative density of approximately 7.9 g/cm{sup 3}--close to 98% of the theoretical value. The P-E hysteresis loop, measured by the Sawyer-Tower circuit, revealed that the remanent polarization (P{sub r}) and coercive field (E{sub c}) were 8.54 {mu}C/cm{sup 2} and 15.6 kV/cm, respectively. The vibration modes of the PZT ceramics were between 150 and 1.5 MHz. Morevoer, under such processing conditions the PZT piezoceramics had uniform grain size distribution less than 1 {mu}m and zero temperature coefficient of resonant frequency (TCF). In summary, the PZT ceramics derived from the sol-gel method were confirmed to possess excellent piezoelectric properties. Furthermore, the processing temperatures were scaled down by 100-200 deg. C, compared to conventional oxide reaction. Finally, from an energy-saving viewpoint, this experiment can potentially make a very positive contribution.

  6. Role of support in adsorption and catalysts on supported metals. II. IR spectroscopic study of adsorption of CO and CO/sub 2/ on Rh/ZrO/sub 2/

    SciTech Connect (OSTI)

    Bredikhin, M.N.; Lokhov, Yu.A.

    1987-12-01T23:59:59.000Z

    IR spectroscopy has been used in a study of the adsorption of CO on Rh/ZrO/sub 2/. It has been found that, the same as in the case of Rh/La/sub 2/O/sub 3/, complexes of CO are formed on the surface of this system, these complexes being coordinated simultaneously by atoms of the metal and surface atoms of the support. This was demonstrated in experiments on selective blockage of the support surface by adsorbed CO/sub 2/.

  7. The influence of pressure on the phase stability of nanocomposite Fe{sub 89}Zr{sub 7}B{sub 4} during heating from energy dispersive x-ray diffraction

    SciTech Connect (OSTI)

    Leary, A. M.; Kernion, S. J.; McHenry, M. E. [Materials Science and Engineering Department, Carnegie Mellon University, 5000 Forbes Ave., Pittsburgh, Pennsylvania 15213 (United States); Lucas, M. S. [Air Force Research Laboratory, Wright-Patterson AFB, Ohio 45433 (United States); Ohodnicki, P. R. [Division of Chemistry and Surface Science, National Energy Technology Laboratory (NETL), 626 Cochrans Mill Road, Pittsburgh, Pennsylvania 15236 (United States); Mauger, L. [California Institute of Technology, W. M. Keck Laboratory 138-78, Pasadena, California 91125 (United States); Park, C.; Kenney-Benson, C. [High Pressure Collaborative Access Team (HPCAT), Geophysical Laboratory, Carnegie Institution of Washington, 9700 S. Cass Ave., Argonne, Illinois 60439 (United States)

    2013-05-07T23:59:59.000Z

    Nanocomposite materials consisting of small crystalline grains embedded within an amorphous matrix show promise for many soft magnetic applications. The influence of pressure is investigated by in situ diffraction of hammer milled Fe{sub 89}Zr{sub 7}B{sub 4} during heating through the {alpha}{yields}{gamma} Fe transition at 0.5, 2.2, and 4.9 GPa. The changes in primary and secondary crystallization onset are described by diffusion and the energy to form a critical nucleus within the framework of classical nucleation theory.

  8. Optical energy storage and reemission based weak localization of light and accompanying random lasing action in disordered Nd{sup 3+} doped (Pb, La)(Zr, Ti)O{sub 3} ceramics

    SciTech Connect (OSTI)

    Xu, Long; Zhao, Hua; Xu, Caixia; Zhang, Siqi [Department of Physics, Harbin Institute of Technology, Harbin 150001 (China); Zhang, Jingwen, E-mail: jingwenz@gmail.com [Department of Physics, Harbin Institute of Technology, Harbin 150001 (China); Boston Applied Technologies, Inc., Woburn, Massachusetts 01801 (United States)

    2014-08-14T23:59:59.000Z

    Multi-mode random lasing action and weak localization of light were evidenced and studied in normally transparent but disordered Nd{sup 3+} doped (Pb,La)(Zr,Ti)O{sub 3} ceramics. Noticeable localized zone and multi-photon process were observed under strong pumping power. A tentative phenomenological physical picture was proposed by taking account of diffusive process, photo-induced scattering, and optical energy storage process as dominant factors in elucidating the weak localization of light observed. Both the decreased transmittance (increased reflectivity) of light and the observed long lasting fading-off phenomenon supported the physical picture proposed by us.

  9. Investigation of temperature dependence of neutron yield and electron screening potential for the d(d, n){sup 3}He reaction proceeding in deuterides ZrD{sub 2} and TiD{sub 2}

    SciTech Connect (OSTI)

    Bystritsky, V. M., E-mail: bystvm@jinr.ru [Joint Institute for Nuclear Research (Russian Federation); Bystritskii, Vit. M. [University of California, Department of Physics and Astronomy (United States); Dudkin, G. N. [National Scientific Research Tomsk Polytechnical University (Russian Federation); Filipowicz, M. [AGH, University of Science and Technology, Faculty of Energy and Fuels (Poland); Gazi, S.; Huran, J. [Institute of Electrical Engineering SAS (Slovakia); Kobzev, A. P. [Joint Institute for Nuclear Research (Russian Federation); Mesyats, G. A. [Lebedev Physical Institute of the Russian Academy of Sciences (Russian Federation); Nechaev, B. A.; Padalko, V. N. [National Scientific Research Tomsk Polytechnical University (Russian Federation); Parzhitskii, S. S. [Joint Institute for Nuclear Research (Russian Federation); Pen'kov, F. M. [Institute of Nuclear Physics NNC (Kazakhstan); Philippov, A. V. [Joint Institute for Nuclear Research (Russian Federation); Kaminskii, V. L. [National Scientific Research Tomsk Polytechnical University (Russian Federation); Tuleushev, Yu. Zh. [Institute of Nuclear Physics NNC (Kazakhstan); Wozniak, J. [AGH, University of Science and Technology, Faculty of Physics and Applied Computer Sciences (Poland)

    2012-08-15T23:59:59.000Z

    The temperature dependence of the enhancement factor for the dd reaction proceeding in TiD{sub 2} and ZrD{sub 2} is investigated. The experiments were carried out at the Hall pulsed ion accelerator (INP, Polytechnic University, Tomsk, Russia) in the deuteron energy interval 7.0-12.0 keV and at temperatures ranging from 20 to 200 Degree-Sign C. The values obtained for the electron screening potentials indicate that the dd reaction enhancement factor does not depend on the target temperature in the range 20-200 Degree-Sign C. This result contradicts the conclusions drawn by the LUNA Collaboration from their work.

  10. Distribution Behavior of U(VI), Pu(IV), Am(III), and Zr(IV) with N,N-Dihexyl Octanamide Under Uranium-Loading Conditions

    SciTech Connect (OSTI)

    Manchanda, V.K.; Ruikar, P.B.; Sriram, S.; Nagar, M.S.; Pathak, P.N.; Gupta, K.K.; Singh, R.K.; Chitnis, R.R.; Dhami, P.S.; Ramanujam, A. [Bhabha Atomic Research Centre (India)

    2001-06-15T23:59:59.000Z

    While the tri-n-butyl phosphate (TBP)-based PUREX process has been the workhorse of the nuclear fuel reprocessing industry for the last four and a half decades, a few drawbacks associated with the use of TBP have caused concern to the separation scientists and technologists. These shortcomings may pose a serious challenge particularly during the reprocessing of (a) short cooled thermal reactor fuels, (b) fast reactor fuels with the larger Pu content and significantly higher burn up, and (c) while treating various waste streams for their disposal to the environment. The N,N-dialkyl aliphatic amides have received particular attention as alternate potential extractants for the reprocessing of spent nuclear fuels in view of (a) the innocuous nature of their degradation products, namely, carboxylic acids/amines and (b) the possibility to incinerate the used solvent leading to reduced volume of secondary waste. The physical and chemical properties of these amides are influenced strongly by the nature of alkyl groups. The extractant N,N-dihexyl octanamide (DHOA) was found to be a promising candidate among a large number of extractants studied. Laboratory batch studies as well as mixer settler studies were performed under process conditions with DHOA and compared with those of TBP. DHOA was found to extract Pu(IV) more efficiently than TBP, both at trace-level concentration as well as under uranium loading conditions. In addition, the extraction behavior of Am(III) and Zr(IV) was studied at varying nitric acid concentrations (1 to 6 M). Extraction behavior of uranium at macroconcentrations (9.9 to 157.7 g/l) was carried out at different temperatures, and it was observed that D{sub U} decreased with the increase in U loading as well as with the increase of temperature (in the range 25 to 45 deg. C) and that the two-phase reaction was exothermic in nature. Mixer settler studies on U(VI) revealed that DHOA is similar to TBP during the extraction cycle but better than TBP during the stripping cycle.

  11. Characterization of solid-phase welds between Ti-6Al-2Sn-4Zr-2Mo-0. 01Si and Ti-13. 5A1-21. 5Nb titanium aluminide

    SciTech Connect (OSTI)

    Baeslack, W.A. III; Juhas, M.; Fraser, H.L. (Ohio State Univ., Columbus, OH (United States)); Broderick, T.F. (Wright Labs., Wright Patterson AFB, OH (United States). Materials Directorate)

    1994-12-01T23:59:59.000Z

    Dissimilar-alloy welds have been produced between Ti-6Al-2Sn-4Zr-2Mo-0.1Si (wt.%) and Ti-13.5Al-21.5Nb (wt.%) titanium aluminide using three different solid-phase welding processes that create significantly different thermo-mechanical conditions at the weld interface. Exposure to supertransus temperatures, appreciable deformation and rapid cooling of the weld interface region during linear-friction welding promote dynamic recrystallization of beta grains and beta decomposition to fine martensitic products. In contrast, diffusion welding at temperatures below the base metal beta transus temperatures and at relatively low pressures minimizes deformation and microstructural variations in the weld interface region relative to the unaffected base metal. During capacitor-discharge resistance spot welding, extremely rapid heating of the weld interface region to near-solidus temperatures, and subsequent rapid cooling, result in the formation of a metastable, ordered-beta microstructure in the Ti-13.5ASl-21.5Nb and fine alpha-prime martensite in the Ti-6Al-2Sn-4Zr-2Mo-0.1Si.

  12. Phase Relations and Elemental Distribution Among Co-Existing Phases in the Ceramics of the Pseudobinary System CaZrTi{sub 2}O{sub 7}-LnAlO{sub 3} (Ln= Nd, Sm)

    SciTech Connect (OSTI)

    Mikhailenko, Natalia [SIA Radon, Moscow, 119121 (Russian Federation); Stefanovsky, Sergey [Center of Advanced Technologies, SIA Radon, 7th Rostovskii lane 2/14, Moscow, 119121 (Russian Federation); Ochkin, Alexander [D. Mendeleev University of Chemical Technology, Moscow (Russian Federation)

    2007-07-01T23:59:59.000Z

    In the ceramics in series (1-x) CaZrTi{sub 2}O{sub 7} - x NdAlO{sub 3} and (1-x) CaZrTi{sub 2}O{sub 7} - x SmAlO{sub 3} (x = 0.25, 0.5 and 0.75) produced by cold pressing and sintering at 1400, 1450 and 1500 deg. C zirconolite was found to be a major phase, perovskite was an extra phase and traces of residual baddeleyite occurred. At x = 0.75 the perovskite was major phase and zirconolite and cubic oxide of fianite or tazheranite type were extra phases. Major Nd and Sm host phase at x = 0.25 was found to be zirconolite (about 65% of total Nd{sub 2}O{sub 3} and 74% of total Sm{sub 2}O{sub 3}). With the x value increasing perovskite becomes major host phase for Nd and Sm accumulating of up to about 92% of total Nd and about 72% of total Sm. As follows from SEM/EDS data Nd and Sm contents in the zirconolite may reach {approx}1 formula unit (fu). (authors)

  13. High-performance self-aligned inversion-channel In{sub 0.53}Ga{sub 0.47}As metal-oxide-semiconductor field-effect-transistors by in-situ atomic-layer-deposited HfO{sub 2}

    SciTech Connect (OSTI)

    Lin, T. D.; Chang, W. H.; Chang, Y. C.; Hong, M., E-mail: raynien@phys.nthu.edu.tw, E-mail: mhong@phys.ntu.edu.tw [Graduate Institute of Applied Physics and Department of Physics, National Taiwan University, Taipei 10617, Taiwan (China); Chu, R. L.; Chang, Y. H. [Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan (China)] [Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Lee, M. Y.; Hong, P. F.; Chen, Min-Cheng [National Nano Device Laboratories, Hsinchu 30076, Taiwan (China)] [National Nano Device Laboratories, Hsinchu 30076, Taiwan (China); Kwo, J., E-mail: raynien@phys.nthu.edu.tw, E-mail: mhong@phys.ntu.edu.tw [Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan (China)

    2013-12-16T23:59:59.000Z

    Self-aligned inversion-channel In{sub 0.53}Ga{sub 0.47}As metal-oxide-semiconductor field-effect-transistors (MOSFETs) have been fabricated using the gate dielectrics of in-situ directly atomic-layer-deposited (ALD) HfO{sub 2} followed by ALD-Al{sub 2}O{sub 3}. There were no surface pretreatments and no interfacial passivation/barrier layers prior to the ALD. TiN/Al{sub 2}O{sub 3} (4?nm)/HfO{sub 2} (1?nm)/In{sub 0.53}Ga{sub 0.47}As/InP MOS capacitors exhibited well-behaved capacitance-voltage characteristics with true inversion behavior, low leakage current densities of ?10{sup ?8}?A/cm{sup 2} at ±1?MV/cm, and thermodynamic stability at high temperatures. Al{sub 2}O{sub 3} (3?nm)/HfO{sub 2} (1?nm)/In{sub 0.53}Ga{sub 0.47}As MOSFETs of 1 ?m gate length, with 700?°C–800?°C rapid thermal annealing in source/drain activation, have exhibited high extrinsic drain current (I{sub D}) of 1.5?mA/?m, transconductance (G{sub m}) of 0.84 mS/?m, I{sub ON}/I{sub OFF} of ?10{sup 4}, low sub-threshold swing of 103?mV/decade, and field-effect electron mobility of 1100 cm{sup 2}/V?·?s. The devices have also achieved very high intrinsic I{sub D} and G{sub m} of 2?mA/?m and 1.2?mS/?m, respectively.

  14. A comparative study of SrO and BaO doping to CeO{sub 2}-ZrO{sub 2}: Characteristic and its catalytic performance for three-way catalysts

    SciTech Connect (OSTI)

    Guo, Jiaxiu, E-mail: guojiaxiu@scu.edu.cn [College of Architecture and Environment, Sichuan University, Chengdu 610065 (China) [College of Architecture and Environment, Sichuan University, Chengdu 610065 (China); National Engineering Research Center for Flue Gas Desulfurization, Chengdu 610065 (China); Shi, Zhonghua, E-mail: shizhonghua@scu.edu.cn [College of Chemistry, Sichuan University, Chengdu 610064 (China)] [College of Chemistry, Sichuan University, Chengdu 610064 (China); Wu, Dongdong [College of Chemistry, Sichuan University, Chengdu 610064 (China)] [College of Chemistry, Sichuan University, Chengdu 610064 (China); Yin, Huaqiang [College of Architecture and Environment, Sichuan University, Chengdu 610065 (China) [College of Architecture and Environment, Sichuan University, Chengdu 610065 (China); National Engineering Research Center for Flue Gas Desulfurization, Chengdu 610065 (China); Gong, Maochu [College of Chemistry, Sichuan University, Chengdu 610064 (China)] [College of Chemistry, Sichuan University, Chengdu 610064 (China); Chen, Yaoqiang [College of Chemistry, Sichuan University, Chengdu 610064 (China) [College of Chemistry, Sichuan University, Chengdu 610064 (China); National Engineering Research Center for Flue Gas Desulfurization, Chengdu 610065 (China)

    2013-02-15T23:59:59.000Z

    Graphical abstract: Display Omitted Highlights: ? The prepared materials have a face-centered cubic structure and nanosize particles. ?Comparing to CZB, aged CZS has 494 ?mol/g of OSC and 30 m{sup 2}/g of surface area. ? CZS and CZB have similar NO sorption and reductive properties and different H{sub 2} uptake. ? T{sub 50} of Pt-Rh/CZS/LA is as low as 199 °C for CO, 228 °C for NO, and 252 °C for C{sub 3}H{sub 8}. ? Pt-Rh/CZS/LA has wider working-window at 320 °C under different ? value. -- Abstract: Ceria-zirconia-strontia (Ce{sub 0.35}Zr{sub 0.55}Sr{sub 0.10}O{sub 1.9}) and ceria-zirconia-baria (Ce{sub 0.35}Zr{sub 0.55}Ba{sub 0.10}O{sub 1.9}) were synthesized using an oxidation-co-precipitation method with hydrogen peroxide (H{sub 2}O{sub 2}) as oxidant. The physical and chemical properties of the prepared materials were investigated using Brunauer–Emmett–Teller surface area characterization, transmission electron microscopy, X-ray diffraction, Raman spectra, X-ray photoelectron spectroscopy, and oxygen pulse reaction. The prepared materials were used in preparing three-way catalysts with low Pt and Rh content. Moreover, catalytic activities were evaluated at a fixed bed under a simulated gaseous mixture. The results are as follows: (1) the prepared materials have a face-centered cubic structure and are nano-sized; (2) aged Ce{sub 0.35}Zr{sub 0.55}Sr{sub 0.10}O{sub 1.9} has higher oxygen storage capacity (494 ?mol/g), better thermal stability (30 m{sup 2}/g), good low-temperature reducibility, and high hydrogen uptake after TPR-redox cycles; (3) the light-off temperature (T{sub 50}) of Pt-Rh/CZS/LA can be as low as 199 °C for CO, 228 °C for NO, and 252 °C for C{sub 3}H{sub 8}; and (4) Pt-Rh/CZS/LA has a fairly wide working-window.

  15. Calculations of the magnetic entropy change in amorphous through a microscopic anisotropic model: Applications to Dy{sub 70}Zr{sub 30} and DyCo{sub 3.4} alloys

    SciTech Connect (OSTI)

    Ranke, P. J. von, E-mail: von.ranke@uol.com.br; Nóbrega, E. P.; Ribeiro, P. O.; Alvarenga, T. S. T.; Lopes, P. H. O.; Sousa, V. S. R. de; Oliveira, N. A. de [Instituto de Física, Universidade do Estado do Rio de Janeiro—UERJ, Rua São Francisco Xavier, 524, 20550-013 Rio de Janeiro (Brazil); Caldas, A. [Sociedade Unificada de Ensino Superior e Cultura, SUESC, 20211-351 Rio de Janeiro (Brazil); Alho, B. P. [Instituto de Aplicação Fernando Rodrigues da Silveira, Universidade do Estado do Rio de Janeiro, Rua Santa Alexandrina, 288, 20260-232 Rio de Janeiro (Brazil); Carvalho, G. [Laboratório Nacional de Luz Sincroton—LNLS, 13083-970 Campinas, São Paulo (Brazil); Magnus, A.

    2014-10-14T23:59:59.000Z

    We report theoretical investigations on the magnetocaloric effect, described by the magnetic entropy change in rare earth—transition metal amorphous systems. The model includes the local anisotropy on the rare earth ions in Harris-Plischke-Zuckermann assumptions. The transition metals ions are treated in terms of itinerant electron ferromagnetism and the magnetic moment of rare earth ions is coupled to the polarized d-band by a local exchange interaction. The magnetocaloric effect was calculated in DyCo{sub 3.4} system, which presents amorphous sperimagnetic configuration. The calculations predict higher refrigerant capacity in the amorphous DyCo{sub 3.4} than in DyCo{sub 2} crystal, highlighting the importance of amorphous magnetocaloric materials. Our calculation of the magnetocaloric effect in Dy{sub 70}Zr{sub 30}, which presents amorphous asperomagnetic configuration, is in good agreement with the experimental result. Furthermore, magnetic entropy changes associated with crystal-amorphous configurations change are estimated.

  16. Synthesis, electrical and thermal properties of Bi{sub 4}V{sub 2-x}Zr{sub x}O{sub 11} (x=0.0 and 0.02) ceramics

    SciTech Connect (OSTI)

    Sahu, S.; Jangid, S.; Roy, M. [Department of Physics, M. L. Sukhadia University, Udaipur-313002 (Rajasthan) (India); Barbar, S. K. [Center for Condensed Matter Sciences, National Taiwan University, Taipei-10617, Taiwan (China)

    2013-02-05T23:59:59.000Z

    Polycrystalline ceramic samples of Bi{sub 4}V{sub 2-x}Zr{sub x}O{sub 11} (x=0.0 and 0.02) have been synthesized by standard solid state reaction method. The formation of the compounds has been verified by room temperature (RT) X-ray diffraction. The frequency and temperature dependent dielectric constant of both the compounds have been measured. The dielectric studies indicate that the materials are highly lossy. The dc conductivity of the materials has been measured as a function of temperature from RT to 653K and their activation energies were calculated using Arrhenius relation {sigma} = {sigma}{sub Masculine-Ordinal-Indicator }exp)-Ea/kT). The heat capacity and heat flow of both the compounds were determined as a function of temperature using Modulated Differential Scanning Calorimetry (MDSC).

  17. Charge control of antiferromagnetism at PbZr{sub 0.52}Ti{sub 0.48}O{sub 3}/La{sub 0.67}Sr{sub 0.33}MnO{sub 3} interface

    SciTech Connect (OSTI)

    Ma, X.; Zhai, H.; Fang, F.; Lüpke, G., E-mail: gxluep@wm.edu [Department of Applied Science, College of William and Mary, 251 Jamestown Road, Williamsburg, Virginia 23187 (United States); Kumar, A. [Department of Physics and Institute for Functional Nanomaterials, University of Puerto Rico, San Juan, Puerto Rico 00931-3343 (United States); CSIR-National Physical Laboratory, New Delhi 110012 (India); Dussan, S.; Katiyar, R. S. [Department of Physics and Institute for Functional Nanomaterials, University of Puerto Rico, San Juan, Puerto Rico 00931-3343 (United States); Zhao, H. B. [Department of Optical Science and Engineering, Fudan University, 220 Handan Road, Shanghai 200433 (China); Scott, J. F. [Department of Physics and Institute for Functional Nanomaterials, University of Puerto Rico, San Juan, Puerto Rico 00931-3343 (United States); Department of Physics, Cavendish Laboratory, University of Cambridge, Cambridge CB3 OHE (United Kingdom)

    2014-03-31T23:59:59.000Z

    The interfacial spin state of the multiferroic heterostructure PbZr{sub 0.52}Ti{sub 0.48}O{sub 3}/La{sub 0.67}Sr{sub 0.33}MnO{sub 3} and its dependence on ferroelectric polarization is investigated with magnetic second-harmonic generation at 78?K. The spin alignment of Mn ions in the first unit cell layer at the heterointerface can be tuned from ferromagnetic to antiferromagnetic exchange coupled, while the bulk magnetization remains unchanged. Multiple domains of both phases coexist as the ferroelectric polarization is switched. The results will help promote the development of new interface-based functionalities and device concepts.

  18. Synthesis and structural transformations of the “glaserite” type zirconosilicate Na{sub 3?x}H{sub 1+x}ZrSi{sub 2}O{sub 8}·yH{sub 2}O

    SciTech Connect (OSTI)

    Kostov-Kytin, Vladislav V., E-mail: vkytin@abv.bg [Institute of Mineralogy and Crystallography, Bulgarian Academy of Science, Acad. G. Bonchev Str., Bl. 107 1113, Sofia (Bulgaria); Nikolova, Rosica P.; Nihtianova, Diana D. [Institute of Mineralogy and Crystallography, Bulgarian Academy of Science, Acad. G. Bonchev Str., Bl. 107 1113, Sofia (Bulgaria)] [Institute of Mineralogy and Crystallography, Bulgarian Academy of Science, Acad. G. Bonchev Str., Bl. 107 1113, Sofia (Bulgaria)

    2012-09-15T23:59:59.000Z

    Highlights: ? Hydrothermal synthesis of hydrous zirconosilicate Na{sub 3}HZrSi{sub 2}O{sub 8}·0.5H{sub 2}O is reported. ? Gradual symmetry lowering is observed upon synthesis treatment. ? This compound's modifications possess “glaserite”-type structure. ? This is a rare case of water-containing material with “glaserite”-type structure. -- Abstract: A hydrous sodium zirconosilicate material with “glaserite” type structure and generalized formula Na{sub 3?x}H{sub 1+x}ZrSi{sub 2}O{sub 8}·yH2O, 0 < x < 3, 0 < y < 1 is synthesized in the system Na{sub 2}O:ZrO{sub 2}:SiO{sub 2}:H{sub 2}O at 200 °C. Its crystal structure is composed of zirconium and silicon polyhedra connected to build layers additionally stacked to form 3D zipper-like network. Within the network there are cavities interconnected to channels with irregular shapes where the sodium atoms and water molecules reside. It is found that with synthesis duration the crystal structure gradually transforms from higher symmetrical into triclinic one. The structure of the triclinic form – Na{sub 3}HZrSi{sub 2}O{sub 8}·0.4H{sub 2}O was refined from powder diffraction data. It crystallizes in the space group P-1 with lattice parameters a = 9.05234, b = 5.56121, c = 6.96219 ?, ? = 92.178, ? = 90.839, ? = 90.288°. To the best of our knowledge the studied compound is the only water-containing material with “glaserite” type structure.

  19. A new Bi{sub 0.5}Na{sub 0.5}TiO{sub 3} based lead-free piezoelectric system with calculated end-member Bi(Zn{sub 0.5}Hf{sub 0.5})O{sub 3}

    SciTech Connect (OSTI)

    Liu, Feng [The Key Laboratory of Inorganic Functional Materials and Devices, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Wahyudi, Olivia; Li, Yongxiang, E-mail: yxli@mail.sic.ac.cn [The Key Laboratory of Inorganic Functional Materials and Devices, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China)

    2014-03-21T23:59:59.000Z

    The phase structure, dielectric and piezoelectric properties of a new lead-free piezoelectric system (1???x)Bi{sub 0.5}Na{sub 0.5}TiO{sub 3}–xBi(Zn{sub 0.5}Hf{sub 0.5})O{sub 3} [(1???x)BNT–xBZH, x?=?0, 0.01, 0.02, 0.03, and 0.04] were investigated. The structure of Bi(Zn{sub 0.5}Hf{sub 0.5})O{sub 3} was calculated using first-principles method and (1???x)BNT–xBZH ceramics were fabricated by conventional solid-state process. At room temperature, a morphotropic phase boundary (MPB) from rhombohedral to pseudocubic is identified near x?=?0.02 by the analysis of X-ray diffraction patterns. The ceramics with MPB near room temperature exhibit excellent electrical properties: the Curie temperature, maximum polarization, remnant polarization, and coercive field are 340?°C, 56.3??C/cm{sup 2}, 43.5??C/cm{sup 2}, and 5.4?kV/mm, respectively, while the maximum positive bipolar strain and piezoelectric coefficient are 0.09% and 92 pC/N, respectively. In addition, a linear relationship between the MPB phase boundary composition and the calculated tetragonality of non-BNT end-member was demonstrated. Thus, this study not only shows a new BNT-based lead-free piezoelectric system but also suggest a new way to predict the composition at MPB a priori when designing new lead-free piezoelectric system.

  20. Ceramic plasma-sprayed coating of melting crucibles for casting metal fuel slugs

    SciTech Connect (OSTI)

    K.H. Kim; C.T. Lee; C.B. Lee; R.S. Fielding; J.R. Kennedy

    2013-10-01T23:59:59.000Z

    Thermal cycling and melt reaction studies of ceramic coatings plasma-sprayed on Nb substrates were carried out to evaluate the performance of barrier coatings for metallic fuel casting applications. Thermal cycling tests of the ceramic plasma-sprayed coatings to 1450 degrees C showed that HfN, TiC, ZrC, and Y2O3 coating had good cycling characteristics with few interconnected cracks even after 20 cycles. Interaction studies by 1550 degrees C melt dipping tests of the plasma-sprayed coatings also indicated that HfN and Y2O3 do not form significant reaction layer between U–20 wt.% Zr melt and the coating layer. Plasma-sprayed Y2O3 coating exhibited the most promising characteristics among HfN, TiC, ZrC, and Y2O3 coating.

  1. Phase evolution studies in CaZrTi{sub 2}O{sub 7}?RE{sub 2}Ti{sub 2}O{sub 7} (RE?=?Nd{sup 3+}, Sm{sup 3+}) system: Futuristic ceramic host matrices for nuclear waste immobilization

    SciTech Connect (OSTI)

    Jafar, M., E-mail: sachary@barc.gov.in; Achary, S. N., E-mail: sachary@barc.gov.in; Tyagi, A. K., E-mail: sachary@barc.gov.in [Chemistry Division, Bhabha Atomic Research Centre, Mumbai-400085 (India)

    2014-04-24T23:59:59.000Z

    Series of compositions with general stoichiometry as Ca{sub 1?x}Zr{sub 1?x}RE{sub 2x}Ti{sub 2}O{sub 7} (RE?=?Nd{sup 3+}, Sm{sup 3+}) were prepared by solid state reaction and characterized by powder x-ray diffraction technique to unravel the phase fields in the title systems. The phase fields in CaZrTi{sub 2}O{sub 7?}Nd{sub 2}Ti{sub 2}O{sub 7} and CaZrTi{sub 2}O{sub 7?}Sm{sub 2}Ti{sub 2}O{sub 7} systems differed significantly at the rareearth rich regions. The common phase fields like zirconolite-2M, zirconolite-4M, cubic perovskite are observed at the zirconolite rich regions of both systems. Depending on the structure of RE{sub 2}Ti{sub 2}O{sub 7} phase, the cubic pyrochlore or monoclinic RE{sub 2}Ti{sub 2}O{sub 7} phases are observed in the studied system. The observed phase fields in these two systems indicate ionic radius of the rare-earth ion has a dominating role in the phase relations. Further details of the phases and their homogeneity are explained in the text of the manuscript.

  2. High temperature solid electrolyte fuel cell with ceramic electrodes

    DOE Patents [OSTI]

    Marchant, David D. (Richland, WA); Bates, J. Lambert (Richland, WA)

    1984-01-01T23:59:59.000Z

    A solid oxide electrolyte fuel cell is described having a central electrolyte comprised of a HfO.sub.2 or ZrO.sub.2 ceramic stabilized and rendered ionically conductive by the addition of Ca, Mg, Y, La, Nd, Sm, Gd, Dy Er, or Yb. The electrolyte is sandwiched between porous electrodes of a HfO.sub.2 or ZrO.sub.2 ceramic stabilized by the addition of a rare earth and rendered electronically conductive by the addition of In.sub.2 O.sub.3. Alternatively, the anode electrode may be made of a metal such as Co, Ni, Ir Pt, or Pd.

  3. Hydrogen Storage Properties of New Hydrogen-Rich BH3NH3-Metal Hydride (TiH2, ZrH2, MgH2, and/or CaH2) Composite Systems

    SciTech Connect (OSTI)

    Choi, Young Joon; Xu, Yimin; Shaw, Wendy J.; Ronnebro, Ewa

    2012-04-19T23:59:59.000Z

    Ammonia borane (AB = NH3BH3) is one of the most attractive materials for chemical hydrogen storage due to its high hydrogen contents of 19.6 wt.%, however, impurity levels of borazine, ammonia and diborane in conjunction with foaming and exothermic hydrogen release calls for finding ways to mitigate the decomposition reactions. In this paper we present a solution by mixing AB with metal hydrides (TiH2, ZrH2, MgH2 and CaH2) which have endothermic hydrogen release in order to control the heat release and impurity levels from AB upon decomposition. The composite materials were prepared by mechanical ball milling, and their H2 release properties were characterized by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The formation of volatile products from decomposition side reactions, such as borazine (N3B3H6) was determined by mass spectrometry (MS). Sieverts type pressure-composition-temperature (PCT) gas-solid reaction instrument was adopted to observe the kinetics of the H2 release reactions of the combined systems and neat AB. In situ 11B MAS-NMR revealed a destabilized decomposition pathway. We found that by adding specific metal hydrides to AB we can eliminate the impurities and mitigate the heat release.

  4. Mechanism and kinetics of carbide dissolution in near alpha Ti-5.6Al-4.8Sn-2Zr-1Mo-0.35Si-0.7Nd titanium alloy

    SciTech Connect (OSTI)

    Zhang, S.Z., E-mail: szzhangyt@163.com [School of Environmental and Materials Engineering, Yantai University, 32 Qingquan Road, Yantai 264005 (China); Li, M.M. [School of Environmental and Materials Engineering, Yantai University, 32 Qingquan Road, Yantai 264005 (China); Yang, R. [Titanium Alloy Laboratory, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016 (China)

    2011-12-15T23:59:59.000Z

    The present work evaluates the influence of bulk carbon content and aging temperature on the stability of carbide in near alpha Ti-5.6Al-4.8Sn-2Zr-1Mo-0.35Si-0.7Nd titanium alloy. The carbide particles were formed during heat treatment in the {beta} phase field and preserved by water quenching. Subsequent aging treatments at 750-850 Degree-Sign C caused partial dissolution of these precipitates, as a result of the peritectoid reaction between the {beta} phase and carbide. The models based on interface reaction controlled dissolution, via uniform atomic detachment, dislocation mechanism or vacancy flow, yielded experimental predictions comparable to the observed dissolution kinetics. Furnace cooling after heat treatment in the {beta} phase field dissolved carbide particles completely, and the microstructure changed from acicular-like or block {alpha} to equiaxed {alpha} with increase of carbon content. - Highlights: Black-Right-Pointing-Pointer Carbide dissolution occurs at precipitate/matrix interfaces, forming {beta}-depleted zone. Black-Right-Pointing-Pointer Peritectoid reaction is responsible for drastic reduction of carbide volume fraction. Black-Right-Pointing-Pointer Slower dissolution rate is accounted by dislocation, vacancy flow, and curvature. Black-Right-Pointing-Pointer Lamellar changed to equiaxed {alpha} with increasing carbon from {beta} furnace cooling.

  5. Anode-supported tubular SOFCs based on BaZr0.1Ce0.7Y0.1Yb0.1O3?? electrolyte fabricated by dip coating

    SciTech Connect (OSTI)

    Chen, Changcheng; Liu, Mingfei; Bai, Yaohui; Yang, Lei; Xie, Erqing; Liu, Meilin

    2011-01-01T23:59:59.000Z

    Anode-supported tubular solid oxide fuel cells (SOFCs) based on a proton and oxide ion mixed conductor, BaZr{sub 0.1}Ce{sub 0.7}Y{sub 0.1}Yb{sub 0.1}O{sub 3 ? ?} (BZCYYb), have been fabricated using a dip coating and co-firing process. This new fabrication technique effectively reduced the Ohmic resistances of tubular cells to ~ 0.1 and ~ 0.3 ? cm{sup 2} at 750 and 600 °C, respectively. Typical tubular cells with Ni-BZCYYb anode, BZCYYb electrolyte, and La{sub 0.6}Sr{sub 0.4}Co{sub 0.2}Fe{sub 0.8}O{sub 3 ? ?} (LSCF)-BZCYYb composite cathode demonstrated much-improved performance, achieving peak power densities of 1.13, 0.81, 0.63, and 0.53 W cm{sup ? 2} at 750, 700, 650, and 600 °C, respectively, when humidified (3 v% water vapor) hydrogen was used as fuel and ambient air as oxidant.

  6. Perovskite-related ZrO{sub 2}-doped SrCo{sub 0.4}Fe{sub 0.6}O{sub 3{minus}{delta}} membrane for oxygen permeation

    SciTech Connect (OSTI)

    Li, S.; Jin, W.; Huang, P.; Xu, N.; Shi, J. [Nanjing Univ. of Chemical Technology (China). Membrane Science and Technology Research Center] [Nanjing Univ. of Chemical Technology (China). Membrane Science and Technology Research Center; Hu, M.Z.C.; Payzant, E.A. [Oak Ridge National Lab., TN (United States)] [Oak Ridge National Lab., TN (United States); Ha, Y.H. [Worcester Polytechnic Inst., MA (United States). Dept. of Chemical Engineering] [Worcester Polytechnic Inst., MA (United States). Dept. of Chemical Engineering

    1999-02-01T23:59:59.000Z

    A typical perovskite La{sub 0.2}Sr{sub 0.8}Co{sub 0.2}Fe{sub 0.8}O{sub 3{minus}{delta}} (LSCF) membrane and a novel perovskite-related ZrO{sub 2}-doped SrCo{sub 0.4}Fe{sub 0.6}O{sub 3{minus}{delta}} (SCFZ) membrane were successfully prepared. The sintered membranes were characterized by an in-situ high-temperature X-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy. Oxygen permeabilities of the two dense membranes were measured in the temperature range of 923 to 1,173 K under a fixed oxygen partial pressure gradient. The results of the oxygen permeation experiment and high-temperature X-ray diffraction in argon atmosphere indicate that the perovskite-related SCFZ membrane has higher oxygen fluxes and is more stable than that of the LSCF membrane at elevated temperatures and reduced oxygen partial pressures.

  7. Preparation and dielectric properties of Ba{sub 0.95}Ca{sub 0.05}Ti{sub 0.8}Zr{sub 0.2}O{sub 3}-polyethersulfone composites

    SciTech Connect (OSTI)

    Wang Fajun; Li Wen; Jiang Hongliu; Xue Mingshan; Lu Jinshan; Yao Junping [School of Materials Science and Engineering, Nanchang Hangkong University, Nanchang 330063 (China)

    2010-02-15T23:59:59.000Z

    We report the preparation and dielectric properties of ceramic-polymer composites using Ba{sub 0.95}Ca{sub 0.05}Ti{sub 0.8}Zr{sub 0.2}O{sub 3} (BCTZ) as a ceramic filler and polyethersulfone (PES) as a polymer matrix. The BCTZ powders were synthesized by a sol-gel method to fabricate BCZT-PES composites. The composites with various BCTZ volume fractions were prepared by a solution mixing and hot-pressing method. The composite with 50 vol % BCTZ showed high dielectric constant ({epsilon}=48.80) and low loss (tan {delta}=0.042) at 1 kHz and room temperature. Such excellent dielectric properties of the composites displayed an acceptable stability within a wide range of temperature (from 20 to 150 deg. C) and frequency (from 100 Hz to 100 kHz). The present work indicates that the BCTZ-PES composite can be a candidate for embedded capacitors.

  8. Microstructures and properties of laser-glazed plasma-sprayed ZrO{sub 2}-YO{sub 1.5}/Ni-22Cr-10Al-1Y thermal barrier coatings

    SciTech Connect (OSTI)

    Tsai, H.L.; Tsai, P.C. [National Taiwan Inst. of Tech., Taipei (Taiwan, Province of China). Dept. of Mechanical Engineering and Technology

    1995-12-01T23:59:59.000Z

    Thermal barrier coatings (TBCs) consisting of two layers with various yttria contents (ZrO{sub 2}-YO{sub 1.5}/Ni-22Cr-10Al-1Y) were plasma sprayed, and parts of the various specimens were glazed by using a pulsed CO{sub 2} laser. All the specimens were then subjected to furnace thermal cycling tests at 1,100 C; the effect of laser glazing on the durability and failure mechanism of the TBCs was then evaluated. From these results, two models were developed to show the failure mechanism of as-sprayed and laser-glazed TBCs: model A, which is thermal-stress dominant, and model V, which is oxidation-stress dominant. For top coats containing cubic phase, cubic and monoclinic phases, or tetragonal and a relatively larger amount of monoclinic phases, whose degradation is thermal-stress dominant, laser glazing improved the durability of TBCs by a factor of about 2 to 6. Segmented cracks that occurred during glazing proved beneficial for accommodating thermal stress and raising the tolerance to oxidation, which resulted in a higher durability. Thermal barrier coatings with top coats containing tetragonal phase had the highest durability. Degradation of such TBCs resulted mainly from oxidation of the bond coats. For top coats with a greater amount of monoclinic phase, thermal mismatch stress occurred during cooling and detrimentally affected durability.

  9. Strong Enhancement of Flux Pinning in YBa2Cu3O7-? Multilayers with Columnar Defects Comprised of Self-Assembled BaZrO3

    SciTech Connect (OSTI)

    Kang, Sukill [ORNL; Leonard, Keith J [ORNL; Martin, Patrick M [ORNL; Li, Jing [ORNL; Goyal, Amit [ORNL

    2007-01-01T23:59:59.000Z

    Multilayer structures comprising YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} (YBCO) films with columns of self-assembled BaZrO{sub 3} (BZO) nanodots with interlayers of CeO{sub 2} or pure YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} were grown on rolling-assisted biaxially textured substrates (RABiTSs) using pulsed laser deposition. A significant enhancement of the critical current density (J{sub c}) was observed for the multilayers compared with a single layer of YBCO + BZO. J{sub c} varies as J{sub c}{approx}H{sup -{alpha}} with a of 0.27 for single layer of YBCO + BZO and 0.34 for both multilayered films. Enhancement of pinning in the multilayers is attributed to the presence of columnar defects comprised of self-assembled nanodots of BZO as well as planar CuO-type stacking defects arising as a result of interfacial reactions in the multilayers.

  10. Radiative rates for E1, E2, M1, and M2 transitions in the Br-like ions Sr IV, Y V, Zr VI, Nb VII, and Mo VIII

    E-Print Network [OSTI]

    Aggarwal, K M

    2015-01-01T23:59:59.000Z

    Energies and lifetimes are reported for the lowest 375 levels of five Br-like ions, namely Sr~IV, Y~V, Zr~VI, Nb~VII, and Mo~VIII, mostly belonging to the 4s$^2$4p$^5$, 4s$^2$4p$^4$4$\\ell$, 4s4p$^6$, 4s$^2$4p$^4$5$\\ell$, 4s$^2$4p$^3$4d$^2$, 4s4p$^5$4$\\ell$, and 4s4p$^5$5$\\ell$ configurations. Extensive configuration interaction has been included and the general-purpose relativistic atomic structure package ({\\sc grasp}) has been adopted for the calculations. Additionally, radiative rates are listed among these levels for all E1, E2, M1, and M2 transitions. From a comparison with the measurements, the majority of our energy levels are assessed to be accurate to better than 2\\%, although discrepancies between theory and experiment for a few are up to 6\\%. An accuracy assessment of the calculated radiative rates (and lifetimes) is more difficult, because no prior results exist for these ions.

  11. Electrochemical characterization of a low modulus Ti-35.5Nb-7.3Zr-5.7Ta alloy in a simulated body fluid using EIS for biomedical applications

    SciTech Connect (OSTI)

    Bhola, R.; Bhola, S. M.; Mishra, B.; Ayers, R. A.; Olson, D. L. [Department of Metallurgical and Materials Engineering, Colorado School of Mines, 1500 Illinois Street, Golden, CO (United States)

    2011-06-23T23:59:59.000Z

    Electrochemical characterization of the low modulus Ti-35.5Nb-7.3Zr-5.7Ta beta alloy (TNZT) has been performed in phosphate buffer saline solution at 37 deg. C using the non destructive electrochemical impedance spectroscopy technique. Measurements were performed at various immersion intervals at the open circuit potential (OCP), which was also monitored with time. Results obtained for TNZT alloy have been compared with those for the commercially used Ti-6Al-4V mixed alloy (Ti64) and the commercially pure titanium (Ti2) alpha alloy. Potentiodynamic polarization was performed to supplement the data obtained from EIS analysis. The TNZT alloy exhibits a two time constant impedance response, whereas the Ti64 and Ti2 alloys display a one time constant behavior. Human fetal osteoblast cells show a better adhesion and a higher cell count for the TNZT alloy compared to the other two alloys. The present investigation is an effort to understand the correlation between the electrochemical, morphological and cellular characteristics of titanium alloys to qualify them for implant applications.

  12. Karnak: the Temple of Amun-Ra-Who-Hears-Prayers

    E-Print Network [OSTI]

    Gallet, Laetitia

    2013-01-01T23:59:59.000Z

    have been necessary to plaster them to a larger thickness ifin a generous layer of plaster, and the ribs and cupulesthe adhesion of the plaster (fig. 6). Figure 6. Peristyle

  13. adc ra fa: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Grant Name, Budget Number Prepare grants materials for submission Prepare materials for experimental use Keep accurate records Borenstein, Elhanan 289 Two...

  14. arthritis ra psoriatic: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    dates: From to Grant Name, Budget Number Prepare grants materials for submission Prepare materials for experimental use Keep accurate records...

  15. atypical ra domain: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    dates: From to Grant Name, Budget Number Prepare grants materials for submission Prepare materials for experimental use Keep accurate records...

  16. ?-RA: a parallel sparse index for genomic read alignment

    E-Print Network [OSTI]

    Kü lekci, M O?uzhan; Hon, Wing-Kai; Shah, Rahul; Vitter, Jeffrey Scott; Xu, Bojian

    2011-07-27T23:59:59.000Z

    Background Genomic read alignment involves mapping (exactly or approximately) short reads from a particular individual onto a pre-sequenced reference genome of the same species. Because all individuals of the same species ...

  17. 2005 Minerals Yearbook RaRe eaRths

    E-Print Network [OSTI]

    , and shipped. substantial stocks of lanthanide concentrates and intermediate and refined compounds were for the petroleum industry and processed cerium and zirconia compounds In 2005, world rare-earth production decreased as did imports of individual rare-earth compounds and mixed rare-earth compounds. U.s. imports

  18. The Athlit ra: Classical and Hellenistic bronze casting

    E-Print Network [OSTI]

    Oron, Asaf

    2001-01-01T23:59:59.000Z

    of Classical and Hellenistic bronze casting technology. Through the use of advanced analytical techniques and careful visual examination, the current study re-evaluates the technology employed in casting the Athlit ram. Newly gathered data, complemented...

  19. argentine reactor ra-6: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    materials is much smaller in a fast reactor than in a thermal reactor. Consequently, metals that in a thermal reactor would severely impair neutron economy are acceptable in a...

  20. The Advanced Research Projects, OAS-RA-11-11

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious RankCombustion |Energy Usage »of Energy StrainClientDesignOfficeThe 21st Century TruckAPRILAudit Report