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Sample records for nvn-89274 cu nvn-89275

  1. NVN-89275 | Open Energy Information

    Open Energy Info (EERE)

    Type NOI Decision Document Date 20101202 Relevant Numbers Lead Agency Doc Number Serial Number NVN-89275 Proposed Action Geophysical surveys. Documents Serial Register Page:...

  2. NVN-89274 | Open Energy Information

    Open Energy Info (EERE)

    Type NOI Decision Document Date 20101202 Relevant Numbers Lead Agency Doc Number Serial Number NVN-89274 Lease Numbers NVN-085716 NVN-086893 NVN-088920 Proposed Action...

  3. Augusta Mountains Geothermal Area | Open Energy Information

    Open Energy Info (EERE)

    Date Decision Date Lead Agency Development Phase(s) Techniques NVN-89274 CU AltaRock Energy Inc 4 November 2010 2 December 2010 BLM GeothermalExploration Geophysical...

  4. Property:NEPA PreApplicationMeetingDate | Open Energy Information

    Open Energy Info (EERE)

    2010 + NVN-89274 + 26 October 2010 + S San Juan Basin EC + 5 November 2008 + Sigurd Red Butte No2 + 19 December 2008 + Southline Transmission Line + 4 April 2012 + Sun Valley...

  5. Hydrodynamic evolution and jet energy loss in Cu + Cu collisions...

    Office of Scientific and Technical Information (OSTI)

    Hydrodynamic evolution and jet energy loss in Cu + Cu collisions Citation Details In-Document Search Title: Hydrodynamic evolution and jet energy loss in Cu + Cu collisions ...

  6. Hydrodynamic evolution and jet energy loss in Cu + Cu collisions...

    Office of Scientific and Technical Information (OSTI)

    Hydrodynamic evolution and jet energy loss in Cu + Cu collisions Prev Next Title: Hydrodynamic evolution and jet energy loss in Cu + Cu collisions Authors: Schenke, Bjrn ; ...

  7. Thermochemical process for recovering Cu from CuO or CuO.sub.2

    DOE Patents [OSTI]

    Richardson, deceased, Donald M.; Bamberger, Carlos E.

    1981-01-01

    A process for producing hydrogen comprises the step of reacting metallic Cu with Ba(OH).sub.2 in the presence of steam to produce hydrogen and BaCu.sub.2 O.sub.2. The BaCu.sub.2 O.sub.2 is reacted with H.sub.2 O to form Cu.sub.2 O and a Ba(OH).sub.2 product for recycle to the initial reaction step. Cu can be obtained from the Cu.sub.2 O product by several methods. In one embodiment the Cu.sub.2 O is reacted with HF solution to provide CuF.sub.2 and Cu. The CuF.sub.2 is reacted with H.sub.2 O to provide CuO and HF. CuO is decomposed to Cu.sub.2 O and O.sub.2. The HF, Cu and Cu.sub.2 O are recycled. In another embodiment the Cu.sub.2 O is reacted with aqueous H.sub.2 SO.sub.4 solution to provide CuSO.sub.4 solution and Cu. The CuSO.sub.4 is decomposed to CuO and SO.sub.3. The CuO is decomposed to form Cu.sub.2 O and O.sub.2. The SO.sub.3 is dissolved to form H.sub.2 SO.sub.4. H.sub.2 SO.sub.4, Cu and Cu.sub.2 O are recycled. In another embodiment Cu.sub.2 O is decomposed electrolytically to Cu and O.sub.2. In another aspect of the invention, Cu is recovered from CuO by the steps of decomposing CuO to Cu.sub.2 O and O.sub.2, reacting the Cu.sub.2 O with aqueous HF solution to produce Cu and CuF.sub.2, reacting the CuF.sub.2 with H.sub.2 O to form CuO and HF, and recycling the CuO and HF to previous reaction steps.

  8. Hydrodynamic evolution and jet energy loss in Cu + Cu collisions

    SciTech Connect (OSTI)

    Schenke, Bjoern; Jeon, Sangyong; Gale, Charles

    2011-04-15

    We present results from a hybrid description of Cu + Cu collisions using (3 + 1)-dimensional hydrodynamics (music) for the bulk evolution and a Monte Carlo simulation (martini) for the evolution of high-momentum partons in the hydrodynamical background. We explore the limits of this description by going to small system sizes and determine the dependence on different fractions of wounded nucleon and binary collisions scaling of the initial energy density. We find that Cu + Cu collisions are well described by the hybrid description at least up to 20% central collisions.

  9. Cu 2 S 3 complex on Cu(111) as a candidate for mass transport...

    Office of Scientific and Technical Information (OSTI)

    Cu 2 S 3 complex on Cu(111) as a candidate for mass transport enhancement Citation Details In-Document Search Title: Cu 2 S 3 complex on Cu(111) as a candidate for mass transport ...

  10. cu | OpenEI Community

    Open Energy Info (EERE)

    ancient building system architect biomimicry building technology cooling cu daylight design problem energy use engineer fred andreas geothermal green building heat transfer...

  11. Science DMZ Implemented at CU Boulder

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

    CU Science Engagement Move your data Programs & Workshops Science Requirements Reviews Case Studies OSCARS Case Studies Science DMZ Case Studies Science DMZ @ UF Science DMZ @ CU ...

  12. Property:NEPA CU Document | Open Energy Information

    Open Energy Info (EERE)

    CU Document Jump to: navigation, search Property Name NEPA CU Document Property Type Page Description CU files for NEPA Docs. Typically Casual Use Documentation consists of a...

  13. Million Cu. Feet Percent of National Total

    Annual Energy Outlook [U.S. Energy Information Administration (EIA)]

    8 Minnesota - Natural Gas 2014 Million Cu. Feet Percent of National Total Million Cu. Feet ... Summary statistics for natural gas - Minnesota, 2010-2014 2010 2011 2012 2013 2014 ...

  14. Phase transformation between Cu(In,Sn){sub 2} and Cu{sub 2}(In,Sn) compounds formed on single crystalline Cu substrate during solid state aging

    SciTech Connect (OSTI)

    Tian, Feifei; Liu, Zhi-Quan Guo, Jingdong

    2014-01-28

    Interfacial reactions between eutectic SnIn and single crystalline Cu during solid-state aging at low temperature were investigated systematically. Three types of phase transformations between Cu(In,Sn){sub 2} layer and Cu{sub 2}(In,Sn) layer were observed, which are Cu(In,Sn){sub 2} grows and Cu{sub 2}(In,Sn) consumes at 40?C, Cu(In,Sn){sub 2} and Cu{sub 2}(In,Sn) grow simultaneously at 60?C, as well as Cu(In,Sn){sub 2} consumes and Cu{sub 2}(In,Sn) grows at 80 and 100?C. According to physicochemical approach, the chemical reactions at Cu/Cu{sub 2}(In,Sn)/Cu(In,Sn){sub 2}/SnIn interfaces were discussed in detail. It was concluded that the diffusion ability of Cu and In atoms dominated different phase transformations. When diffusion constants k{sub 1In2}?>?8/3k{sub 1Cu2} Cu(In,Sn){sub 2} will grow, and if k{sub 1Cu2}???k{sub 1In2} Cu{sub 2}(In,Sn) will grow. Both Cu(In,Sn){sub 2} and Cu{sub 2}(In,Sn) can grow in the condition of k{sub 1In2} ? k{sub 1Cu2}. The values of k{sub 1Cu2} and k{sub 1In2} at different temperatures on (100)Cu and (111)Cu substrate were also calculated or estimated by analyzing the growth kinetics of the compound layers.

  15. Cu

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

    o u n d t o CCQ E (la r ge , r a t e o f Q E) 2 5 % o f t o t a l e ve n t r a t e Eve n t Se le ct io n 3 s u b e ve n t s - & + , - e - , + + e + 1...

  16. Origins of optical absorption characteristics of Cu2+ complexes...

    Office of Scientific and Technical Information (OSTI)

    Origins of optical absorption characteristics of Cu2+ complexes in solutions Citation Details In-Document Search Title: Origins of optical absorption characteristics of Cu2+ ...

  17. Performance and mix measurements of indirect drive Cu doped Be...

    Office of Scientific and Technical Information (OSTI)

    Performance and mix measurements of indirect drive Cu doped Be implosions Citation Details In-Document Search Title: Performance and mix measurements of indirect drive Cu doped Be ...

  18. Understanding the Deactivation Mechanisms of Cu/Zeolite SCR Catalysts...

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

    Deactivation Mechanisms of CuZeolite SCR Catalysts in Diesel Application Understanding the Deactivation Mechanisms of CuZeolite SCR Catalysts in Diesel Application To understand ...

  19. Investigation of Sulfur Deactivation on Cu/Zeolite SCR Catalysts...

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

    Sulfur Deactivation on CuZeolite SCR Catalysts in Diesel Application Investigation of Sulfur Deactivation on CuZeolite SCR Catalysts in Diesel Application Investigation of Sulfur ...

  20. Cu-Cu direct bonding achieved by surface method at room temperature

    SciTech Connect (OSTI)

    Utsumi, Jun [Advanced Technology Research Center, Mitsubishi Heavy Industries, Ltd., 1-8-1 Sachiura, Kanazawa-ku, Yokohama 236-8515 (Japan); Ichiyanagi, Yuko, E-mail: yuko@ynu.ac.jp [Department of Physics, Graduate School of Engineering, Yokohama National University, Tokiwadai, Hodogaya, Yokohama 240-8501 (Japan)

    2014-02-20

    The metal bonding is a key technology in the processes for the microelectromechanical systems (MEMS) devices and the semiconductor devices to improve functionality and higher density integration. Strong adhesion between surfaces at the atomic level is crucial; however, it is difficult to achieve close bonding in such a system. Cu films were deposited on Si substrates by vacuum deposition, and then, two Cu films were bonded directly by means of surface activated bonding (SAB) at room temperature. The two Cu films, with the surface roughness Ra about 1.3nm, were bonded by using SAB at room temperature, however, the bonding strength was very weak in this method. In order to improve the bonding strength between the Cu films, samples were annealed at low temperatures, between 323 and 473 K, in air. As the result, the Cu-Cu bonding strength was 10 times higher than that of the original samples without annealing.

  1. Direct Epoxidation of Propylene over Stabilized Cu+ Surface Sites on Ti Modified Cu2O

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Yang, X.; Kattel, S.; Xiong, K.; Mudiyanselage, K.; Rykov, S.; Senanayake, S. D.; Rodriguez, J. A.; Liu, P.; Stacchiola, D. J.; Chen, J. G.

    2015-07-17

    Direct propylene epoxidation by O2 is a challenging reaction because of the strong tendency for complete combustion. Results from the current study demonstrate the feasibility to tune the epoxidation selectivity by generating highly dispersed and stabilized Cu+ active sites in a TiCuOx mixed oxide. The TiCuOx surface anchors the key surface intermediate, oxametallacycle, leading to higher selectivity for epoxidation of propylene.

  2. Theoretical study on the CuH + H. -->. Cu + H/sub 2/ reaction pathway

    SciTech Connect (OSTI)

    Ruiz, M.E.; Garcia-Prieto, J.; Poulain, E.; Ozin, G.A.; Poirier, R.A.; Matta, S.M.; Czismadia, I.G.; Gracie, C.; Novaro, O.

    1986-01-16

    Quite recently, experimental results on the CuH + H ..-->.. Cu + H/sub 2/ thermal matrix phase reaction were reported, indicating that it proceeds with no activation barrier, and no evidence exists for an intermediate CuH/sub 2/ species at 10-13 K. Here the authors present a theoretical study of this reaction using variational and perturbational configuration interaction calculations with a relativistic pseudopotential (PSHONDO-CIPSI) set of programs. The results confirm the lack of a barrier and provide an explanation as to why the CuH/sub 2/ species may not be observed. 11 references, 3 figures, 3 tables.

  3. Million Cu. Feet Percent of National Total

    U.S. Energy Information Administration (EIA) Indexed Site

    2 Alaska - Natural Gas 2014 Million Cu. Feet Percent of National Total Million Cu. Feet Percent of National Total Total Net Movements: - Industrial: Dry Production: Vehicle Fuel: Deliveries to Consumers: Residential: Electric Power: Commercial: Total Delivered: Table S2. Summary statistics for natural gas - Alaska, 2010-2014 2010 2011 2012 2013 2014 Number of Producing Gas Wells at End of Year 269 277 185 R 159 170 Production (million cubic feet) Gross Withdrawals From Gas Wells 127,417 112,268

  4. Million Cu. Feet Percent of National Total

    U.S. Energy Information Administration (EIA) Indexed Site

    6 District of Columbia - Natural Gas 2014 Million Cu. Feet Percent of National Total Million Cu. Feet Percent of National Total Total Net Movements: - Industrial: Dry Production: Vehicle Fuel: Deliveries to Consumers: Residential: Electric Power: Commercial: Total Delivered: Table S9. Summary statistics for natural gas - District of Columbia, 2010-2014 2010 2011 2012 2013 2014 Number of Producing Gas Wells at End of Year 0 0 0 0 0 Production (million cubic feet) Gross Withdrawals From Gas Wells

  5. Million Cu. Feet Percent of National Total

    U.S. Energy Information Administration (EIA) Indexed Site

    4 Massachusetts - Natural Gas 2014 Million Cu. Feet Percent of National Total Million Cu. Feet Percent of National Total Total Net Movements: - Industrial: Dry Production: Vehicle Fuel: Deliveries to Consumers: Residential: Electric Power: Commercial: Total Delivered: Table S23. Summary statistics for natural gas - Massachusetts, 2010-2014 2010 2011 2012 2013 2014 Number of Producing Gas Wells at End of Year 0 0 0 0 0 Production (million cubic feet) Gross Withdrawals From Gas Wells 0 0 0 0 0

  6. Million Cu. Feet Percent of National Total

    U.S. Energy Information Administration (EIA) Indexed Site

    50 North Dakota - Natural Gas 2014 Million Cu. Feet Percent of National Total Million Cu. Feet Percent of National Total Total Net Movements: - Industrial: Dry Production: Vehicle Fuel: Deliveries to Consumers: Residential: Electric Power: Commercial: Total Delivered: Table S36. Summary statistics for natural gas - North Dakota, 2010-2014 2010 2011 2012 2013 2014 Number of Producing Gas Wells at End of Year 188 239 211 200 200 Production (million cubic feet) Gross Withdrawals From Gas Wells

  7. Million Cu. Feet Percent of National Total

    U.S. Energy Information Administration (EIA) Indexed Site

    6 Washington - Natural Gas 2014 Million Cu. Feet Percent of National Total Million Cu. Feet Percent of National Total Total Net Movements: - Industrial: Dry Production: Vehicle Fuel: Deliveries to Consumers: Residential: Electric Power: Commercial: Total Delivered: Table S49. Summary statistics for natural gas - Washington, 2010-2014 2010 2011 2012 2013 2014 Number of Producing Gas Wells at End of Year 0 0 0 0 0 Production (million cubic feet) Gross Withdrawals From Gas Wells 0 0 0 0 0 From Oil

  8. Comparative study of the alloying effect on the initial oxidation of Cu-Au(100) and Cu-Pt(100)

    SciTech Connect (OSTI)

    Luo, Langli; Zhou, Guangwen; Kang, Yihong; Yang, Judith C.; Su, Dong; Stach, Eric A.

    2014-03-24

    Using in situ transmission electron microscopy, we show that the oxidation of the Cu-Au(100) results in the formation of Cu{sub 2}O islands that deeply embed into the Cu-Au substrate while the oxidation of the Cu-Pt(100) leads to the formation of Cu{sub 2}O islands that highly protrude above the Cu-Pt substrate. Their difference is attributed to the different mobilities of Pt and Au in the Cu base alloys for which the sluggish mobility of Pt in Cu results in trapped Pt atoms at the oxide/alloy interface while the faster mobility of Au in Cu leads to enhanced rehomogenization of the alloy composition.

  9. Million Cu. Feet Percent of National Total

    U.S. Energy Information Administration (EIA) Indexed Site

    0 Alabama - Natural Gas 2014 Million Cu. Feet Percent of National Total Million Cu. Feet Percent of National Total Total Net Movements: - Industrial: Dry Production: Vehicle Fuel: Deliveries to Consumers: Residential: Electric Power: Commercial: Total Delivered: Table S1. Summary statistics for natural gas - Alabama, 2010-2014 2010 2011 2012 2013 2014 Number of Producing Gas Wells at End of Year 7,026 7,063 6,327 R 6,165 6,118 Production (million cubic feet) Gross Withdrawals From Gas Wells

  10. Million Cu. Feet Percent of National Total

    U.S. Energy Information Administration (EIA) Indexed Site

    0 Colorado - Natural Gas 2014 Million Cu. Feet Percent of National Total Million Cu. Feet Percent of National Total Total Net Movements: - Industrial: Dry Production: Vehicle Fuel: Deliveries to Consumers: Residential: Electric Power: Commercial: Total Delivered: Table S6. Summary statistics for natural gas - Colorado, 2010-2014 2010 2011 2012 2013 2014 Number of Producing Gas Wells at End of Year 28,813 30,101 32,000 R 32,468 38,346 Production (million cubic feet) Gross Withdrawals From Gas

  11. Million Cu. Feet Percent of National Total

    U.S. Energy Information Administration (EIA) Indexed Site

    8 Florida - Natural Gas 2014 Million Cu. Feet Percent of National Total Million Cu. Feet Percent of National Total Total Net Movements: - Industrial: Dry Production: Vehicle Fuel: Deliveries to Consumers: Residential: Electric Power: Commercial: Total Delivered: Table S10. Summary statistics for natural gas - Florida, 2010-2014 2010 2011 2012 2013 2014 Number of Producing Gas Wells at End of Year 0 0 0 0 0 Production (million cubic feet) Gross Withdrawals From Gas Wells 0 0 17,182 16,459 19,742

  12. Million Cu. Feet Percent of National Total

    U.S. Energy Information Administration (EIA) Indexed Site

    4 Hawaii - Natural Gas 2014 Million Cu. Feet Percent of National Total Million Cu. Feet Percent of National Total Total Net Movements: - Industrial: Dry Production: Vehicle Fuel: Deliveries to Consumers: Residential: Electric Power: Commercial: Total Delivered: Table S13. Summary statistics for natural gas - Hawaii, 2010-2014 2010 2011 2012 2013 2014 Number of Producing Gas Wells at End of Year 0 0 0 0 0 Production (million cubic feet) Gross Withdrawals From Gas Wells 0 0 0 0 0 From Oil Wells 0

  13. Million Cu. Feet Percent of National Total

    U.S. Energy Information Administration (EIA) Indexed Site

    6 Idaho - Natural Gas 2014 Million Cu. Feet Percent of National Total Million Cu. Feet Percent of National Total Total Net Movements: - Industrial: Dry Production: Vehicle Fuel: Deliveries to Consumers: Residential: Electric Power: Commercial: Total Delivered: Table S14. Summary statistics for natural gas - Idaho, 2010-2014 2010 2011 2012 2013 2014 Number of Producing Gas Wells at End of Year 0 0 0 0 0 Production (million cubic feet) Gross Withdrawals From Gas Wells 0 0 0 0 0 From Oil Wells 0 0

  14. Million Cu. Feet Percent of National Total

    U.S. Energy Information Administration (EIA) Indexed Site

    4 Kansas - Natural Gas 2014 Million Cu. Feet Percent of National Total Million Cu. Feet Percent of National Total Total Net Movements: - Industrial: Dry Production: Vehicle Fuel: Deliveries to Consumers: Residential: Electric Power: Commercial: Total Delivered: Table S18. Summary statistics for natural gas - Kansas, 2010-2014 2010 2011 2012 2013 2014 Number of Producing Gas Wells at End of Year 22,145 25,758 24,697 R 23,792 24,354 Production (million cubic feet) Gross Withdrawals From Gas Wells

  15. Million Cu. Feet Percent of National Total

    U.S. Energy Information Administration (EIA) Indexed Site

    8 Louisiana - Natural Gas 2014 Million Cu. Feet Percent of National Total Million Cu. Feet Percent of National Total Total Net Movements: - Industrial: Dry Production: Vehicle Fuel: Deliveries to Consumers: Residential: Electric Power: Commercial: Total Delivered: Table S20. Summary statistics for natural gas - Louisiana, 2010-2014 2010 2011 2012 2013 2014 Number of Producing Gas Wells at End of Year 19,137 21,235 19,792 R 19,528 19,251 Production (million cubic feet) Gross Withdrawals From Gas

  16. Million Cu. Feet Percent of National Total

    U.S. Energy Information Administration (EIA) Indexed Site

    4 New Mexico - Natural Gas 2014 Million Cu. Feet Percent of National Total Million Cu. Feet Percent of National Total Total Net Movements: - Industrial: Dry Production: Vehicle Fuel: Deliveries to Consumers: Residential: Electric Power: Commercial: Total Delivered: Table S33. Summary statistics for natural gas - New Mexico, 2010-2014 2010 2011 2012 2013 2014 Number of Producing Gas Wells at End of Year 44,748 32,302 28,206 R 27,073 27,957 Production (million cubic feet) Gross Withdrawals From

  17. Million Cu. Feet Percent of National Total

    U.S. Energy Information Administration (EIA) Indexed Site

    6 Oregon - Natural Gas 2014 Million Cu. Feet Percent of National Total Million Cu. Feet Percent of National Total Total Net Movements: - Industrial: Dry Production: Vehicle Fuel: Deliveries to Consumers: Residential: Electric Power: Commercial: Total Delivered: Table S39. Summary statistics for natural gas - Oregon, 2010-2014 2010 2011 2012 2013 2014 Number of Producing Gas Wells at End of Year 26 24 27 R 26 28 Production (million cubic feet) Gross Withdrawals From Gas Wells 1,407 1,344 770 770

  18. Science DMZ Implemented at CU Boulder

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

    CU Science Engagement Move your data Programs & Workshops Science Requirements Reviews Case Studies OSCARS Case Studies Science DMZ Case Studies Science DMZ @ UF Science DMZ @ CU Science DMZ @ Penn & VTTI Science DMZ @ NOAA Science DMZ @ NERSC Science DMZ @ ALS Multi-facility Workflow Case Study Contact Us Technical Assistance: 1 800-33-ESnet (Inside US) 1 800-333-7638 (Inside US) 1 510-486-7600 (Globally) 1 510-486-7607 (Globally) Report Network Problems: trouble@es.net Provide Web Site

  19. The Effects of Hydrothermal Agingon a Commercial Cu SCR Catalyst

    Broader source: Energy.gov [DOE]

    Examines the effect of hydrothermal aging on the Nox reduction over a commercial Cu-zeolite SCR catalyst.

  20. Cu(II) promotes amyloid pore formation

    SciTech Connect (OSTI)

    Zhang, Hangyu; Rochet, Jean-Christophe; Stanciu, Lia A.

    2015-08-14

    The aggregation of α-synuclein is associated with dopamine neuron death in Parkinson's disease. There is controversy in the field over the question of which species of the aggregates, fibrils or protofibrils, are toxic. Moreover, compelling evidence suggested the exposure to heavy metals to be a risk of PD. Nevertheless, the mechanism of metal ions in promoting PD remains unclear. In this research, we investigated the structural basis of Cu(II) induced aggregation of α-synuclein. Using transmission electron microscopy experiments, Cu(II) was found to promote in vitro aggregation of α-synuclein by facilitating annular protofibril formation rather than fibril formation. Furthermore, neuroprotective baicalein disaggregated annular protofibrils accompanied by considerable decrease of β-sheet content. These results strongly support the hypothesis that annular protofibrils are the toxic species, rather than fibrils, thereby inspiring us to search novel therapeutic strategies for the suppression of the toxic annular protofibril formation. - Highlights: • Cu(II) promoted the annular protofibril formation of α-synuclein in vitro. • Cu(II) postponed the in vitro fibrillization of α-synuclein. • Neuroprotective baicalein disaggregated annular protofibrils.

  1. OPERATIONS AND PERFORMANCE OF RHIC AS A CU-CU COLLIDER.

    SciTech Connect (OSTI)

    PILAT, R.; AHRENS, L.; BAI, M.; BARTON, D.S.; ET AL.

    2005-05-16

    The 5th year of RHIC operations, started in November 2004 and expected to last till June 2005, consists of a physics run with Cu-Cu collisions at 100 GeV/u followed by one with polarized protons (pp) at 100 GeV [l]. We will address here the overall performance of the RHIC complex used for the first time as a Cu-Cu collider, and compare it with previous operational experience with Au, PP and asymmetric d-Au collisions. We will also discuss operational improvements, such as a {beta}* squeeze to 85cm in the high luminosity interaction regions from the design value of 1m, system improvements, machine performance and limitations, and address reliability and uptime issues.

  2. Bi-Se doped with Cu, p-type semiconductor

    DOE Patents [OSTI]

    Bhattacharya, Raghu Nath; Phok, Sovannary; Parilla, Philip Anthony

    2013-08-20

    A Bi--Se doped with Cu, p-type semiconductor, preferably used as an absorber material in a photovoltaic device. Preferably the semiconductor has at least 20 molar percent Cu. In a preferred embodiment, the semiconductor comprises at least 28 molar percent of Cu. In one embodiment, the semiconductor comprises a molar percentage of Cu and Bi whereby the molar percentage of Cu divided by the molar percentage of Bi is greater than 1.2. In a preferred embodiment, the semiconductor is manufactured as a thin film having a thickness less than 600 nm.

  3. Unexpected crystal and magnetic structures in MnCu4In and MnCu4Sn (Journal

    Office of Scientific and Technical Information (OSTI)

    Article) | SciTech Connect SciTech Connect Search Results Journal Article: Unexpected crystal and magnetic structures in MnCu4In and MnCu4Sn Citation Details In-Document Search Title: Unexpected crystal and magnetic structures in MnCu4In and MnCu4Sn We discovered a new compound MnCu4In with its own hexagonal structure type (hP12-P63mc, ternary ordered derivative of the hexagonal MgZn2-type) that becomes ferromagnetic at TC = 540 K. This transition temperature is higher than that found in the

  4. Method of producing .sup.67 Cu

    DOE Patents [OSTI]

    O'Brien, Jr., Harold A.; Barnes, John W.; Taylor, Wayne A.; Thomas, Kenneth E.; Bentley, Glenn E.

    1984-01-01

    A method of producing carrier-free .sup.67 Cu by proton spallation combined with subsequent chemical separation and purification is disclosed. A target consisting essentially of pressed zinc oxide is irradiated with a high energy, high current proton beam to produce a variety of spallogenic nuclides, including .sup.67 Cu and other copper isotopes. The irradiated target is dissolved in a concentrated acid solution to which a palladium salt is added. In accordance with the preferred method, the spallogenic copper is twice coprecipitated with palladium, once with metallic zinc as the precipitating agent and once with hydrogen sulfide as the precipitating agent. The palladium/copper precipitate is then dissolved in an acid solution and the copper is separated from the palladium by liquid chromatography on an anion exchange resin.

  5. Method for producing /sup 67/Cu

    DOE Patents [OSTI]

    O'Brien, H.A. Jr.; Barnes, J.W.; Taylor, W.A.; Thomas, K.E.; Bentley, G.E.

    A method of producing carrier-free /sup 67/Cu by proton spallation combined with subsequent chemical separation and purification is disclosed. A target consisting essentially of pressed zinc oxide is irradiated with a high energy, high current proton beam to produce a variety of spallogenic nuclides, including /sup 67/Cu and other copper isotopes. The irradiated target is dissolved in a concentrated acid solution to which a palladium salt is added. In accordance with the preferred method, the spallogenic copper is twice coprecipitated with palladium, once with metallic zinc as the precipitating agent and once with hydrogen sulfide as the precipitating agent. The palladium/copper precipitate is then dissolved in an acid solution and the copper is separated from the palladium by liquid chromatography on an anion exchange resin.

  6. Magnetic dipole moments of {sup 57,58,59}Cu

    SciTech Connect (OSTI)

    Cocolios, T. E.; Andreyev, A. N.; Bastin, B.; Bree, N.; Buescher, J.; Elseviers, J.; Gentens, J.; Huyse, M.; Kudryavtsev, Yu.; Pauwels, D.; Bergh, P. Van den; Van Duppen, P.; Sonoda, T.

    2010-01-15

    In-gas-cell laser spectroscopy of the isotopes {sup 57,58,59,63,65}Cu has been performed at the LISOL facility using the 244.164-nm optical transition from the atomic ground state of copper. A detailed discussion on the hyperfine structure of {sup 63}Cu is presented. The magnetic dipole moments of the isotopes {sup 57,58,59,65}Cu are extracted based on that of {sup 63}Cu. The new value mu=+0.479(13)mu{sub N} is proposed for {sup 58}Cu, consistent with that of a pip{sub 3/2} x nup{sub 3/2} ground-state configuration. Spin assignments for the radioactive isotopes {sup 57,58,59}Cu are confirmed. The isotope shifts between the different isotopes are also given and discussed.

  7. Multi-component Cu-Strengthened Steel Welding Simulations: Atom...

    Office of Scientific and Technical Information (OSTI)

    Steel Welding Simulations: Atom Probe Tomography and Synchrotron X-ray Diffraction Analyses Citation Details In-Document Search Title: Multi-component Cu-Strengthened Steel Welding ...

  8. Enhanced Photocatalytic Property of Cu Doped Sodium Niobate

    SciTech Connect (OSTI)

    Xu, Jianbin; Zhang, Feng; Sun, Bingyang; Du, Yingge; Li, Guoqiang; Zhang, Weifeng

    2015-09-29

    We investigate the photocatalytic activity of Cu doped NaNbO3 powder sample prepared by the modified polymer complex method. The photocatalytic activity of hydrogen evolution from methanol aqueous solution was improved by Cu 2.6 at% doping. The photocatalytic degradation of rhodamine B under visible light irradiation was enhanced in comparison with pure NaNbO3. Cu inctroduction improved the adsorption property of NaNbO3, judging from the Fourier transform infrared spectra. Moreover, the ultraviolet light excitation in Cu doped sample was found to accelerate the mineralized process.

  9. Understanding NOx SCR Mechanism and Activity on Cu/Chabazite...

    Office of Scientific and Technical Information (OSTI)

    Book: Understanding NOx SCR Mechanism and Activity on CuChabazite Structures throughout the Catalyst Life Cycle Citation Details In-Document Search Title: Understanding NOx SCR...

  10. [Purification of {sup 67}Cu]. Progress report

    SciTech Connect (OSTI)

    DeNardo, S.J.

    1994-09-01

    This report documents progress made in several areas of research and describes results which have not yet been published. These areas include: Purification of {sup 67}Cu; Macrocyclic chelates for targeted therapy; Studies of biologic activation associated with molecular receptor increase and tumor response in ChL6/L6 protocol patients; Lym-1 single chain genetically engineered molecules; Analysis of molecular genetic coded messages to enhance tumor response; Human dosimetry and therapeutic human use radiopharmaceuticals; studies in phantoms; Quantitative SPECT; Preclinical studies; and Clinical studies.

  11. New Resolved Resonance Region Evaluation for 63Cu and 65Cu for Nuclear Criticality Safety Program

    SciTech Connect (OSTI)

    Sobes, Vladimir; Leal, Luiz C; Guber, Klaus H; Forget, Benoit; Kopecky, S.; Schillebeeckx, P.; Siegler, P.

    2014-01-01

    A new resolved resonance region evaluation of 63Cu and 65Cu was done in the energy region from 10-5 eV to 99.5 keV. The R-Matrix SAMMY method using the Reich-Moore approximation was used to create a new set of consistent resonance parameters. The new evaluation was based on three experimental transmission data sets; two measured at ORELA and one from MITR, and two radiative capture experimental data sets from GELINA. A total of 141 new resonances were identied for 63Cu and 117 for 65Cu. The corresponding set of external resonances for each isotope was based on the identied resonances above 99.5 keV from the ORELA transmission data. The negative external levels (bound levels) were determined to match the dierential thermal cross section measured at the MITR. Double dierential elastic scattering cross sections were calculated from the new set of resonance parameters. Benchmarking calculations were carried out on a set of ICSBEP benchmarks. This work is in support of the DOE Nuclear Criticality Safety Program.

  12. Unexpected crystal and magnetic structures in MnCu4In and MnCu4Sn

    SciTech Connect (OSTI)

    Provino, A.; Paudyal, D.; Fornasini, ML; Dhiman, I.; Dhar, SK.; Das, A.; Mudryk, Y.; Manfrinetti, P.; Pecharsky, VK

    2013-01-29

    We discovered a new compound MnCu4In with its own hexagonal structure type (hP12-P63mc, ternary ordered derivative of the hexagonal MgZn2-type) that becomes ferromagnetic at TC = 540 K. This transition temperature is higher than that found in the MnCu2In and MnCu2Sn alloys. In contrast, the homologous compound MnCu4Sn, which crystallizes in the cubic MgCu4Sn-type, orders antiferromagnetically with TN = 110 K. The neutron diffraction studies show ferromagnetic spin orientation in the {1 0 1} plane in MnCu4In with a magnetic moment of 4.5 ?B/Mn at 22 K, and a corresponding value of 4.7 ?B/Mn in the antiferromagnetic MnCu4Sn with propagation vector View the MathML source. The first-principles electronic structure calculations show that the unexpected difference in both magnetic and crystal structures of MnCu4In and MnCu4Sn is due to the difference in the Mn-3d bands and exchange interactions relating to different crystal anisotropy, coordination numbers, and interatomic distances.

  13. Non-uniform Aging on Super Duty Diesel Truck Aged Urea Cu/Zeolite...

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

    Aging on Super Duty Diesel Truck Aged Urea CuZeolite SCR Catalysts Non-uniform Aging on Super Duty Diesel Truck Aged Urea CuZeolite SCR Catalysts CuZeolite SCR catalysts aged ...

  14. Antiferromagnetism in EuCu2As2 and EuCu1.82Sb2 single crystals

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Anand, V. K.; Johnston, D. C.

    2015-05-07

    Single crystals of EuCu2As2 and EuCu2Sb2 were grown from CuAs and CuSb self-flux, respectively. The crystallographic, magnetic, thermal, and electronic transport properties of the single crystals were investigated by room-temperature x-ray diffraction (XRD), magnetic susceptibility χ versus temperature T, isothermal magnetization M versus magnetic field H, specific heat Cp(T), and electrical resistivity ρ(T) measurements. EuCu2As2 crystallizes in the body-centered tetragonal ThCr2Si2-type structure (space group I4/mmm), whereas EuCu2Sb2 crystallizes in the related primitive tetragonal CaBe2Ge2-type structure (space group P4/nmm). The energy-dispersive x-ray spectroscopy and XRD data for the EuCu2Sb2 crystals showed the presence of vacancies on the Cu sites, yielding themore » actual composition EuCu1.82Sb2. The ρ(T) and Cp(T) data reveal metallic character for both EuCu2As2 and EuCu1.82Sb2. Antiferromagnetic (AFM) ordering is indicated from the χ(T),Cp(T), and ρ(T) data for both EuCu2As2 (TN = 17.5 K) and EuCu1.82Sb2 (TN = 5.1 K). In EuCu1.82Sb2, the ordered-state χ(T) and M(H) data suggest either a collinear A-type AFM ordering of Eu+2 spins S = 7/2 or a planar noncollinear AFM structure, with the ordered moments oriented in the tetragonal ab plane in either case. This ordered-moment orientation for the A-type AFM is consistent with calculations with magnetic dipole interactions. As a result, the anisotropic χ(T) and isothermal M(H) data for EuCu2As2, also containing Eu+2 spins S = 7/2, strongly deviate from the predictions of molecular field theory for collinear AFM ordering and the AFM structure appears to be both noncollinear and noncoplanar.« less

  15. Function Specific Analysis of the Thermal Durability of Cu-Zeolite...

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

    Function Specific Analysis of the Thermal Durability of Cu-Zeolite SCR Catalyst Function Specific Analysis of the Thermal Durability of Cu-Zeolite SCR Catalyst Presentation given ...

  16. Deactivation Mechanism of Cu/Zeolite SCR Catalyst Due to Reductive...

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

    Mechanism of CuZeolite SCR Catalyst Due to Reductive Hydrothermal Aging Deactivation Mechanism of CuZeolite SCR Catalyst Due to Reductive Hydrothermal Aging Better control for ...

  17. Mitigation of the Impact of Pt Contamination on Cu-Zeolite SCR...

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

    the Impact of Pt Contamination on Cu-Zeolite SCR Catalyst Performance Mitigation of the Impact of Pt Contamination on Cu-Zeolite SCR Catalyst Performance Investigates operating ...

  18. Application of cluster-plus-glue-atom model to barrierless CuNiTi and CuNiTa films

    SciTech Connect (OSTI)

    Li, Xiaona, E-mail: lixiaona@dlut.edu.cn; Ding, Jianxin; Wang, Miao; Dong, Chuang [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, Dalian 116024 (China); Chu, Jinn P. [Department of Materials Science and Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan (China)

    2014-11-01

    To improve the thermal stability of copper and avoid its diffusion into surrounding dielectrics or interfacial reactions with them, the authors applied the cluster-plus-glue-atom model to investigate barrierless CuNiM (M?=?Ti or Ta) seed layers. The dissolution of the third element (Ti or Ta) in the Cu lattice with the aid of Ni significantly improved the thermal stability of the Cu seed layer. The appropriate M/Ni (M?=?Ti or Ta) ratio was selected to obtain a low resistivity: the resistivity was as low as 2.5??? cm for the (Ti{sub 1.5/13.5}Ni{sub 12/13.5}){sub 0.3}Cu{sub 99.7} film and 2.8??? cm for the (Ta{sub 1.1/13.1}Ni{sub 12/13.1}){sub 0.4}Cu{sub 99.6} film after annealing at 500?C for 1?h. After annealing at 500?C for 40?h, the two films remained stable without forming a Cu{sub 3}Si compound. The authors confirmed that the range of applications of the cluster-plus-glue-atom model could be extended. Therefore, a third element M with negative enthalpies of mixing with both Cu and Ni could be selected, under the premise that the mixing enthalpy of MNi is more negative than that of MCu.

  19. How to stabilize highly active Cu+ cations in a mixed-oxide catalyst

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Mudiyanselage, Kumudu; Luo, Si; Kim, Hyun You; Yang, Xiaofang; Baber, Ashleigh E.; Hoffmann, Friedrich M.; Senanayake, Sananayake; Rodriguez, Jose A.; Chen, Jingguang G.; Liu, Ping; et al

    2015-09-12

    Mixed-metal oxides exhibit novel properties that are not present in their isolated constituent metal oxides and play a significant role in heterogeneous catalysis. In this study, a titanium-copper mixed-oxide (TiCuOx) film has been synthesized on Cu(111) and characterized by complementary experimental and theoretical methods. At sub-monolayer coverages of titanium, a Cu2O-like phase coexists with TiCuOx and TiOx domains. When the mixed-oxide surface is exposed at elevated temperatures (600–650 K) to oxygen, the formation of a well-ordered TiCuOx film occurs. Stepwise oxidation of TiCuOx shows that the formation of the mixed-oxide is faster than that of pure Cu2O. As the Timore » coverage increases, Ti-rich islands (TiOx) form. The adsorption of CO has been used to probe the exposed surface sites on the TiOx–CuOx system, indicating the existence of a new Cu+ adsorption site that is not present on Cu2O/Cu(111). Adsorption of CO on Cu+ sites of TiCuOx is thermally more stable than on Cu(111), Cu2O/Cu(111) or TiO2(110). The Cu+ sites in TiCuOx domains are stable under both reducing and oxidizing conditions whereas the Cu2O domains present on sub-monolayer loads of Ti can be reduced or oxidized under mild conditions. Furthermore, the results presented here demonstrate novel properties of TiCuOx films, which are not present on Cu(111), Cu2O/Cu(111), or TiO2(110), and highlight the importance of the preparation and characterization of well-defined mixed-metal oxides in order to understand fundamental processes that could guide the design of new materials.« less

  20. Photoelectrochemistry, Electronic Structure, and Bandgap Sizes of Semiconducting Cu(I)-Niobates and Cu(I)-Tantalates

    SciTech Connect (OSTI)

    Maggard, Paul A.

    2013-11-14

    Semiconducting metal-oxides have remained of intense research interest owing to their potential for achieving efficient solar-driven photocatalytic reactions in aqueous solutions that occur as a result of their bandgap excitation. The photocatalytic reduction of water or carbon dioxide to generate hydrogen or hydrocarbon fuels, respectively, can be driven on p-type (photocathodic) electrodes with suitable band energies. However, metal-oxide semiconductors are typically difficult to dope as p-type with a high mobility of carriers. The supported research led to the discovery of new p-type Cu(I)-niobate and Cu(I)-tantalate film electrodes that can be prepared on FTO glass. New high-purity flux syntheses and the full structural determination of several Cu(I)-containing niobates and tantalates have been completed, as well as new investigations of their optical and photoelectrochemical properties and electronic structures via density-functional theory calculations. For example, CuNbO3, Cu5Ta11O30 and CuNb3O8 were prepared in high purity and their structures were characterized by both single-crystal and powder X-ray diffraction techniques. These two classes of Cu(I)-containing compounds exhibit optical bandgap sizes ranging from ~1.3 eV to ~2.6 eV. Photoelectrochemical measurements of these compounds show strong photon-driven cathodic currents that confirm the p-type semiconductor behavior of CuNbO3, CuNb3O8, and Cu5Ta11O30. Incident-photon-to-current efficiencies are measured that approach greater than ~1%. Electronic-structure calculations based on density functional theory reveal the visible-light absorption stems from a nearly-direct bandgap transition involving a copper-to-niobium or tantalum (d10 to d0) charge-transfer excitations.

  1. Structure and electrochemical properties of nanometer Cu substituted ?-nickel hydroxide

    SciTech Connect (OSTI)

    Bao, Jie; Zhu, Yanjuan; Zhang, Zhongju; Xu, Qingsheng; Zhao, Weiren; Chen, Jian; Zhang, Wei; Han, Quanyong

    2013-02-15

    Graphical abstract: Display Omitted Highlights: ? Cu substituted ?-nickel hydroxide was prepared by ultrasonic assisted precipitation. ? The XRD peaks are anisotropic broadening. ? The electrode for 0.9 wt.% Cu has the highest capacity of 310 mAh/g at 0.2 C. -- Abstract: Nanometer Cu-substituted ?-nickel hydroxide was synthesized by means of ultrasonic-assisted precipitation. Particle size distribution (PSD) measurement, X-ray diffraction (XRD), and high-resolution transmission electron microscope (HR-TEM) were used to characterize the physical properties of the synthesized samples. The results indicate that the average particle size of the samples is about 96110 nm and the XRD diffraction peaks are anisotropic broadening. The crystal grains are mainly polycrystal structure with columnar or needle-like morphology, containing many defects. With increase of Cu content, the shape of primary particles transform from columnar to needle-like. The influences of doping amounts of Cu on the electrochemical performance were investigated through constant current charge/discharge and cyclic voltammetric measurements. The specific capacity increases initially and then decreases with increasing Cu-doping ratio, the electrode C containing 0.9 wt.% Cu shows the maximum discharge capacity of 310 mAh/g at 0.2 C, and it has the lowest charging voltage, higher discharge voltage plateau, better cycle performance and larger proton diffusion coefficient than the other electrodes.

  2. Coupled skyrmion sublattices in Cu2OSeO3

    SciTech Connect (OSTI)

    Langner, M.C.; Roy,, S.; Mishra, S. K.; Lee, J. C. T.; Shi,, X. W.; Hossain, M. A.; Chuang, Y.-D.; Seki, S.; Tokura, Y.; Kevan, S. D.; Schoenlein, R. W.

    2014-04-18

    We report the observation of a skyrmion lattice in the chiral multiferroic insulator Cu2OSeO3 using Cu L3-edge resonant soft x-ray diffraction. We observe the unexpected existence of two distinct skyrmion sub-lattices that arise from inequivalent Cu sites with chemically identical coordination numbers but different magnetically active orbitals . The skyrmion sublattices are rotated with respect to each other implying a long wavelength modulation of the lattice. The modulation vector is controlled with an applied magnetic field, associating this Moir'e-like phase with a continuous phase transition. Our findings will open a new class of science involving manipulation of quantum topological states.

  3. Role of Cu-Ion Doping in Cu-α-MnO2 Nanowire Electrocatalysts for the Oxygen Reduction Reaction

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Davis, Danae J.; Lambert, Timothy N.; Vigil, Julian A.; Rodriguez, Mark A.; Brumbach, Michael T.; Coker, Eric N.; Limmer, Steven J.

    2014-07-09

    The role of Cu-ion doping in α-MnO2 electrocatalysts for the oxygen reduction reaction in alkaline electrolyte was investigated. Copper doped α-MnO2 nanowires (Cu-α-MnO2) were prepared with varying amounts of Cu2+ using a solvothermal method. The electrocatalytic dataindicates that Cu-α-MnO2 nanowires have higher terminal current densities, enhanced kinetic rate constants, and improved charge transfer resistances that trend with Cu-content, exceeding values attained by α-MnO2 alone. The observed improvement in catalytic behavior correlates with an increase in Mn3+ content for the Cu-α-MnO2 nanowires. The Mn3+/Mn4+ couple is themediator for the rate-limiting redox driven O2-/OH- exchange. It is proposed that O2 adsorbs viaanmore » axial site (the eg orbital on the Mn3+ d4 ion) at the surface, or at edge defects, of the nanowireand that the increase in covalent nature of the nanowire with Cu-ion doping leads to stabilization of O2 adsorbates and faster rates of reduction. This work is applicable to other manganese oxide electrocatalysts and shows for the first time there is a correlation for manganese oxides between electrocatalytic activity for the ORR in alkaline electrolyte and an increase in Mn3+ character of the oxide.« less

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

    SciTech Connect (OSTI)

    Min Xu

    2008-08-18

    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.

  5. Improving properties of Mg with AlCu additions

    SciTech Connect (OSTI)

    Rashad, Muhammad; Pan, Fusheng; Asif, Muhammad; Hussain, Shahid; Saleem, Muhammad

    2014-09-15

    The present work reports improvement in tensile properties of the Mg matrix reinforced with micron-sized copperaluminum particulate hybrids. The AlCu particulate hybrids were incorporated into the Mg matrix through powder metallurgy method. The synthesized alloys exhibited homogeneously dispersed Mg{sub 2}Cu particles in the matrix, therefore leading to a 110% increase in yield strength (221 MPa) and a 72% enhancement in ultimate tensile strength (284 MPa) by addition of 1.0 wt.%Al0.6 wt.%Cu particle hybrids. Optical microscopy, scanning election microscopy, transmission electron microscopy and X-ray diffraction were used to investigate the microstructure and intermetallic phases of the synthesized alloys. - Highlights: Mg matrix is reinforced with AlCu particulate hybrids. Powder metallurgic method is used to fabricate the alloys. Tensile strength and ductility were increased simultaneously.

  6. Arizona - Natural Gas 2014 Million Cu. Feet Percent of

    U.S. Energy Information Administration (EIA) Indexed Site

    4 Arizona - Natural Gas 2014 Million Cu. Feet Percent of National Total Million Cu. Feet Percent of National Total Total Net Movements: - Industrial: Dry Production: Vehicle Fuel: Deliveries to Consumers: Residential: Electric Power: Commercial: Total Delivered: Table S3. Summary statistics for natural gas - Arizona, 2010-2014 2010 2011 2012 2013 2014 Number of Producing Gas Wells at End of Year 5 5 5 5 5 Production (million cubic feet) Gross Withdrawals From Gas Wells 183 168 117 72 106 From

  7. Characteristics of Cu stabilized Nb3Al strands with low Cu ratio

    SciTech Connect (OSTI)

    Kikuchi, A.; Yamada, R.; Barzi, E.; Kobayashi, M.; Lamm, M.; Nakagawa, K.; Sasaki, K.; Takeuchi, T.; Turrioni, D.; Zlobin, A.V.; /NIMC, Tsukuba /Fermilab /Hitachi, Tsuchiura Works /KEK, Tsukuba

    2008-12-01

    Characteristics of recently developed F4-Nb{sub 3}Al strand with low Cu ratio are described. The overall J{sub c} of the Nb{sub 3}Al strand could be easily increased by decreasing of the Cu ratio. Although the quench of a pulse-like voltage generation is usually observed in superconducting unstable conductor, the F4 strand with a low Cu ratio of 0.61 exhibited an ordinary critical transition of gradual voltage generation. The F4 strand does not have magnetic instabilities at 4.2 K because of the tantalum interfilament matrix. The overall J{sub c} of the F4 strand achieved was 80-85% of the RRP strand. In the large mechanical stress above 100 MPa, the overall J{sub c} of the F4 strand might be comparable to that of high J{sub c} RRP-Nb{sub 3}Sn strands. The Rutherford cable with a high packing factor of 86.5% has been fabricated using F4 strands. The small racetrack magnet, SR07, was also fabricated by a 14 m F4 cable. The quench current, I{sub q}, of SR07 were obtained 22.4 kA at 4.5 K and 25.2 kA at 2.2 K. The tantalum matrix Nb{sub 3}Al strands are promising for the application of super-cooled high-field magnets as well as 4.2 K operation magnets.

  8. Cu--Pd--M hydrogen separation membranes

    DOE Patents [OSTI]

    Do{hacek over }an, Omer N; Gao, Michael C; Young, Rongxiang Hu; Tafen, De Nyago

    2013-12-17

    The disclosure provides an H2 separation membrane comprised of an allow having the composition Cu.Sub.(100-x-y)Pd.sub.xM.sub.y, where x is from about 35 to about 50 atomic percent and where y is from greater than 0 to about 20 atomic percent, and where M consists of magnesium, yttrium, aluminum, titanium, lanthanum, or combinations thereof. The M elements act as strong stabilizers for the B2 phase of the allow, and extend the critical temperature of the alloy for a given hydrogen concentration and pressure. Due to the phase stabilization and the greater temperature range over which a B2 phase can be maintained, the allow is well suited for service as a H2 separation membrane, particularly when applicable conditions are established or cycled above about 600.degree. C. over the course of expected operations. In certain embodiments, the B2 phase comprises at least 60 estimated volume percent of the allow at a steady-state temperature of 400.degree. C. The B2 phase stability is experimentally validated through HT-XRD.

  9. Modified Ni-Cu catalysts for ethanol steam reforming

    SciTech Connect (OSTI)

    Dan, M.; Mihet, M.; Almasan, V.; Borodi, G.; Katona, G.; Muresan, L.; Lazar, M. D.

    2013-11-13

    Three Ni-Cu catalysts, having different Cu content, supported on γ-alumina were synthesized by wet co-impregnation method, characterized and tested in the ethanol steam reforming (ESR) reaction. The catalysts were characterized for determination of: total surface area and porosity (N{sub 2} adsorption - desorption using BET and Dollimer Heal methods), Ni surface area (hydrogen chemisorption), crystallinity and Ni crystallites size (X-Ray Diffraction), type of catalytic active centers (Hydrogen Temperature Programmed Reduction). Total surface area and Ni crystallites size are not significantly influenced by the addition of Cu, while Ni surface area is drastically diminished by increasing of Cu concentration. Steam reforming experiments were performed at atmospheric pressure, temperature range 150-350°C, and ethanol - water molar ration of 1 at 30, using Ar as carrier gas. Ethanol conversion and hydrogen production increase by the addition of Cu. At 350°C there is a direct connection between hydrogen production and Cu concentration. Catalysts deactivation in 24h time on stream was studied by Transmission Electron Microscopy (TEM) and temperature-programmed reduction (TPR) on used catalysts. Coke deposition was observed at all studied temperatures; at 150°C amorphous carbon was evidenced, while at 350°C crystalline, filamentous carbon is formed.

  10. Growth, characterization and electrochemical properties of hierarchical CuO nanostructures for supercapacitor applications

    SciTech Connect (OSTI)

    Krishnamoorthy, Karthikeyan; Kim, Sang-Jae

    2013-09-01

    Graphical abstract: - Highlights: Hierarchical CuO nanostructures were grown on Cu foil. Monoclinic phase of CuO was grown. XPS analysis revealed the presence of Cu(2p{sub 3/2}) and Cu(2p{sub 1/2}) on the surfaces. Specific capacitance of 94 F/g was achieved for the CuO using cyclic voltammetry. Impedance spectra show their pseudo capacitor applications. - Abstract: In this paper, we have investigated the electrochemical properties of hierarchical CuO nanostructures for pseudo-supercapacitor device applications. Moreover, the CuO nanostructures were formed on Cu substrate by in situ crystallization process. The as-grown CuO nanostructures were characterized using X-ray diffraction (XRD), Fourier transform-infra red spectroscopy (FT-IR), X-ray photoelectron spectroscopy and field emission-scanning electron microscope (FE-SEM) analysis. The XRD and FT-IR analysis confirm the formation of monoclinic CuO nanostructures. FE-SEM analysis shows the formation of leave like hierarchical structures of CuO with high uniformity and controlled density. The electrochemical analysis such as cyclic voltammetry and electrochemical impedance spectroscopy studies confirms the pseudo-capacitive behavior of the CuO nanostructures. Our experimental results suggest that CuO nanostructures will create promising applications of CuO toward pseudo-supercapacitors.

  11. Analysis of the structure, configuration, and sizing of Cu and Cu oxide nanoparticles generated by fs laser ablation of solid target in liquids

    SciTech Connect (OSTI)

    Santillan, J. M. J.; Videla, F. A.; Schinca, D. C.; Scaffardi, L. B.; Fernandez van Raap, M. B.

    2013-04-07

    We report on the analysis of structure, configuration, and sizing of Cu and Cu oxide nanoparticles (Nps) produced by femtosecond (fs) laser ablation of solid copper target in liquids. Laser pulse energy ranged between 500 {mu}J and 50 {mu}J. Water and acetone were used to produce the colloidal suspensions. The study was performed through optical extinction spectroscopy using Mie theory to fit the full experimental spectra, considering free and bound electrons size dependent contributions to the metal dielectric function. Raman spectroscopy and AFM technique were also used to characterize the sample. Considering the possible oxidation of copper during the fabrication process, two species (Cu and Cu{sub 2}O) arranged in two structures (bare core or core-shell) and in two configuration types (Cu-Cu{sub 2}O or Cu{sub 2}O-Cu) were considered for the fitting depending on the laser pulse energy and the surrounding media. For water at high energy, it can be observed that a Cu-Cu{sub 2}O configuration fits the experimental spectra of the colloidal suspension, while for decreasing energy and below a certain threshold, a Cu{sub 2}O-Cu configuration needs to be included for the optimum fit. Both species coexist for energies below 170 {mu}J for water. On the other hand, for acetone at high energy, optimum fit of the full spectrum suggests the presence a bimodal Cu-Cu{sub 2}O core-shell Nps distribution while for decreasing energy and below a 70 {mu}J threshold energy value, Cu{sub 2}O-Cu core-shell Nps must be included, together with the former configuration, for the fit of the full spectrum. We discuss possible reasons for the changes in the structural configuration of the core-shell Nps.

  12. Magnetic dipole moments of {sup 58}Cu and {sup 59}Cu by in-source laser spectroscopy

    SciTech Connect (OSTI)

    Stone, N. J.; Koester, U.; Stone, J. Rikovska; Fedorov, D. V.; Fedoseyev, V. N.; Flanagan, K. T.; Hass, M.; Lakshmi, S.

    2008-06-15

    Online measurements of the magnetic dipole moments and isotope shifts of {sup 58}Cu and {sup 59}Cu by the in-source laser spectroscopy method are reported. The results for the magnetic moments are {mu} ({sup 58}Cu) =+0.52(8) {mu}{sub N},{mu}({sup 59}Cu) =+1.84(3) {mu}{sub N} and for the isotope shifts {delta}{nu}{sup 59,65}=1.72(22) GHz and {delta}{nu}{sup 58,65}=1.99(30) GHz in the transition from the 3d{sup 10}4s {sup 2}S{sub 1/2} ground state to the 3d{sup 10}4p {sup 2}P{sub 1/2} state in Cu I. The magnetic moment of {sup 58}Cu is discussed in the context of the strength of the subshell closure at {sup 56}Ni, additivity rules and large-scale shell model calculations.

  13. Ab initio molecular dynamics simulations of short-range order in Zr50Cu45Al5 and Cu50Zr45Al5 metallic glasses

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Huang, Yuxiang; Huang, Li; Wang, C. Z.; Kramer, M. J.; Ho, K. M.

    2016-02-01

    In this study, comparative analysis between Zr-rich Zr50Cu45Al5 and Cu-rich Cu50Zr45Al5 metallic glasses (MGs) is extensively performed to locate the key structural motifs accounting for their difference of glass forming ability. Here we adopt ab initio molecular dynamics simulations to investigate the local atomic structures of Zr50Cu45Al5 and Cu50Zr45Al5 MGs. A high content of icosahedral-related (full and distorted) orders was found in both samples, while in the Zr-rich MG full icosahedrons <0,0,12,0> is dominant, and in the Cu-rich one the distorted icosahedral orders, especially <0,2,8,2> and <0,2,8,1>, are prominent. And the <0,2,8,2> polyhedra in Cu50Zr45Al5 MG mainly originate from Al-centeredmore » clusters, while the <0,0,12,0> in Zr50Cu45Al5 derives from both Cu-centered clusters and Al-centered clusters. These difference may be ascribed to the atomic size difference and chemical property between Cu and Zr atoms. The relatively large size of Zr and large negative heat of mixing between Zr and Al atoms, enhancing the packing density and stability of metallic glass system, may be responsible for the higher glass forming ability of Zr50Cu45Al5.« less

  14. A Window on Surface Explosions: Tartaric Acid on Cu(110)

    SciTech Connect (OSTI)

    Mhatre, B. S.; Pushkarev, V.; Holsclaw, B.; Lawton, T. J.; Sykes, E. C. H.; Gellman, A. J.

    2013-04-18

    Autocatalytic reaction mechanisms are observed in a range of important chemical processes including catalysis, radical-mediated explosions, and biosynthesis. Because of their complexity, the microscopic details of autocatalytic reaction mechanisms have been difficult to study on surfaces and heterogeneous catalysts. Autocatalytic decomposition reactions of S,S- and R,R-tartaric acid (TA) adsorbed on Cu(110) offer molecular-level insight into aspects of these processes, which until now, were largely a matter of speculation. The decomposition of TA/Cu(110) is initiated by a slow, irreversible process that forms vacancies in the adsorbed TA layer, followed by a vacancy-mediated, explosive decomposition process that yields CO{sub 2} and small hydrocarbon products. Initiation of the explosive decomposition of TA/Cu(110) has been studied by measurement of the reaction kinetics, time-resolved low energy electron diffraction (LEED), and time-resolved scanning tunneling microscopy (STM). Initiation results in a decrease in the local coverage of TA and a concomitant increase in the areal vacancy concentration. Observations of explosive TA decomposition on the Cu(651)S surface suggest that initiation does not occur at structural defects in the surface, as has been suggested in the past. Once the vacancy concentration reaches a critical value, the explosive, autocatalytic decomposition step dominates the TA decomposition rate. The onset of the explosive decomposition of TA on Cu(110) is accompanied by the extraction of Cu atoms from the surface to form a (±6,7; {-+}2,1) overlayer that is readily observable using LEED and STM. The explosive decomposition step is second-order in vacancy concentration and accelerates with increasing extent of reaction.

  15. How to stabilize highly active Cu+ cations in a mixed-oxide catalyst

    SciTech Connect (OSTI)

    Mudiyanselage, Kumudu; Luo, Si; Kim, Hyun You; Yang, Xiaofang; Baber, Ashleigh E.; Hoffmann, Friedrich M.; Senanayake, Sananayake; Rodriguez, Jose A.; Chen, Jingguang G.; Liu, Ping; Stacchiola, Dario J.

    2015-09-12

    Mixed-metal oxides exhibit novel properties that are not present in their isolated constituent metal oxides and play a significant role in heterogeneous catalysis. In this study, a titanium-copper mixed-oxide (TiCuOx) film has been synthesized on Cu(111) and characterized by complementary experimental and theoretical methods. At sub-monolayer coverages of titanium, a Cu2O-like phase coexists with TiCuOx and TiOx domains. When the mixed-oxide surface is exposed at elevated temperatures (600–650 K) to oxygen, the formation of a well-ordered TiCuOx film occurs. Stepwise oxidation of TiCuOx shows that the formation of the mixed-oxide is faster than that of pure Cu2O. As the Ti coverage increases, Ti-rich islands (TiOx) form. The adsorption of CO has been used to probe the exposed surface sites on the TiOxCuOx system, indicating the existence of a new Cu+ adsorption site that is not present on Cu2O/Cu(111). Adsorption of CO on Cu+ sites of TiCuOx is thermally more stable than on Cu(111), Cu2O/Cu(111) or TiO2(110). The Cu+ sites in TiCuOx domains are stable under both reducing and oxidizing conditions whereas the Cu2O domains present on sub-monolayer loads of Ti can be reduced or oxidized under mild conditions. Furthermore, the results presented here demonstrate novel properties of TiCuOx films, which are not present on Cu(111), Cu2O/Cu(111), or TiO2(110), and highlight the importance of the preparation and characterization of well-defined mixed-metal oxides in order to understand fundamental processes that could guide the design of new materials.

  16. Pb-free Sn-Ag-Cu ternary eutectic solder

    DOE Patents [OSTI]

    Anderson, I.E.; Yost, F.G.; Smith, J.F.; Miller, C.M.; Terpstra, R.L.

    1996-06-18

    A Pb-free solder includes a ternary eutectic composition consisting essentially of about 93.6 weight % Sn-about 4.7 weight % Ag-about 1.7 weight % Cu having a eutectic melting temperature of about 217 C and variants of the ternary composition wherein the relative concentrations of Sn, Ag, and Cu deviate from the ternary eutectic composition to provide a controlled melting temperature range (liquid-solid ``mushy`` zone) relative to the eutectic melting temperature (e.g. up to 15 C above the eutectic melting temperature). 5 figs.

  17. Itinerant magnetism in metallic CuFe2Ge2

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Shanavas, K. V.; Singh, David J.; He, Ruihua

    2015-03-25

    Theoretical calculations are performed to understand the electronic structure and magnetic properties of CuFe2Ge2. The band structure reveals large electron density N(EF) at the Fermi level suggesting a strong itinerant character of magnetism. The Fermi surface is dominated by two dimensional sheet like structures, with potentially strong nesting between them. The magnetic ground state appears to be ferromagnetic along a and antiferromagnetic in other directions. The results show that CuFe2Ge2 is an antiferromagnetic metal, with similarities to the Fe-based superconductors; such as magnetism with substantial itinerant character and coupling between magnetic order and electrons at the Fermi energy.

  18. Origins of optical absorption characteristics of Cu2+ complexes in

    Office of Scientific and Technical Information (OSTI)

    solutions (Journal Article) | SciTech Connect Origins of optical absorption characteristics of Cu2+ complexes in solutions Citation Details In-Document Search Title: Origins of optical absorption characteristics of Cu2+ complexes in solutions Authors: Qiu, S R ; Wood, B C ; Ehrmann, P R ; Demos, S G ; Miller, P E ; Schaffers, K I ; Suratwala, T I Publication Date: 2015-02-27 OSTI Identifier: 1234585 Report Number(s): LLNL-JRNL-668007 DOE Contract Number: AC52-07NA27344 Resource Type: Journal

  19. Pb-free Sn-Ag-Cu ternary eutectic solder

    DOE Patents [OSTI]

    Anderson, Iver E.; Yost, Frederick G.; Smith, John F.; Miller, Chad M.; Terpstra, Robert L.

    1996-06-18

    A Pb-free solder includes a ternary eutectic composition consisting essentially of about 93.6 weight % Sn-about 4.7 weight % Ag-about 1.7 weight % Cu having a eutectic melting temperature of about 217.degree. C. and variants of the ternary composition wherein the relative concentrations of Sn, Ag, and Cu deviate from the ternary eutectic composition to provide a controlled melting temperature range (liquid-solid "mushy" zone) relative to the eutectic melting temperature (e.g. up to 15.degree. C. above the eutectic melting temperature).

  20. Distinct oxygen hole doping in different layers of Sr₂CuO4-δ/La₂CuO₄ superlattices

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Smadici, S.; Lee, J. C. T.; Rusydi, A.; Logvenov, G.; Bozovic, I.; Abbamonte, P.

    2012-03-28

    X-ray absorption in Sr₂CuO4-δ/La₂CuO₄ (SCO/LCO) superlattices shows a variable occupation with doping of a hole state different from holes doped for x≲xoptimal in bulk La2-xSrxCuO₄ and suggests that this hole state is on apical oxygen atoms and polarized in the a-b plane. Considering the surface reflectivity gives a good qualitative description of the line shapes of resonant soft x-ray scattering. The interference between superlattice and surface reflections was used to distinguish between scatterers in the SCO and the LCO layers, with the two hole states maximized in different layers of the superlattice.

  1. Origin of Novel Diffusions of Cu and Ag in Semiconductors: The...

    Office of Scientific and Technical Information (OSTI)

    Origin of Novel Diffusions of Cu and Ag in Semiconductors: The Case of CdTe Prev Next Title: Origin of Novel Diffusions of Cu and Ag in Semiconductors: The Case of CdTe ...

  2. High Chalcocite Cu2S: A Solid-Liquid Hybrid Phase (Journal Article...

    Office of Scientific and Technical Information (OSTI)

    High Chalcocite Cu2S: A Solid-Liquid Hybrid Phase Title: High Chalcocite Cu2S: A Solid-Liquid Hybrid Phase Authors: Wang, Lin-Wang Publication Date: 2012-02-24 OSTI Identifier: ...

  3. High-power Laser Interaction With Low-density C-Cu Foams (Journal...

    Office of Scientific and Technical Information (OSTI)

    High-power Laser Interaction With Low-density C-Cu Foams Citation Details In-Document Search Title: High-power Laser Interaction With Low-density C-Cu Foams You are accessing a ...

  4. Solid-solution CrCoCuFeNi high-entropy alloy thin films synthesized...

    Office of Scientific and Technical Information (OSTI)

    Solid-solution CrCoCuFeNi high-entropy alloy thin films synthesized by sputter deposition Title: Solid-solution CrCoCuFeNi high-entropy alloy thin films synthesized by sputter ...

  5. Broken Symmetry in the Pseudogap State of YBa2Cu3O6+x (Technical...

    Office of Scientific and Technical Information (OSTI)

    Technical Report: Broken Symmetry in the Pseudogap State of YBa2Cu3O6+x Citation Details In-Document Search Title: Broken Symmetry in the Pseudogap State of YBa2Cu3O6+x You are ...

  6. Deformation behavior of Nb nanowires in TiNiCu shape memory alloy...

    Office of Scientific and Technical Information (OSTI)

    in TiNiCu shape memory alloy matrix This content will become publicly available on August 18, 2016 Title: Deformation behavior of Nb nanowires in TiNiCu shape memory alloy matrix ...

  7. Sulfur Effect and Performance Recovery of a DOC + CSF + Cu-Zeolite...

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

    Sulfur Effect and Performance Recovery of a DOC + CSF + Cu-Zeolite SCR System Sulfur Effect and Performance Recovery of a DOC + CSF + Cu-Zeolite SCR System effect and performance ...

  8. High strength-high conductivity Cu-Fe composites produced by powder compaction/mechanical reduction

    DOE Patents [OSTI]

    Verhoeven, J.D.; Spitzig, W.A.; Gibson, E.D.; Anderson, I.E.

    1991-08-27

    A particulate mixture of Cu and Fe is compacted and mechanically reduced to form an ''in-situ'' Cu-Fe composite having high strength and high conductivity. Compaction and mechanical reduction of the particulate mixture are carried out at a temperature and time at temperature selected to avoid dissolution of Fe into the Cu matrix particulates to a harmful extent that substantially degrades the conductivity of the Cu-Fe composite. 5 figures.

  9. High strength-high conductivity Cu--Fe composites produced by powder compaction/mechanical reduction

    DOE Patents [OSTI]

    Verhoeven, John D.; Spitzig, William A.; Gibson, Edwin D.; Anderson, Iver E.

    1991-08-27

    A particulate mixture of Cu and Fe is compacted and mechanically reduced to form an "in-situ" Cu-Fe composite having high strength and high conductivity. Compaction and mechanical reduction of the particulate mixture are carried out at a temperature and time at temperature selected to avoid dissolution of Fe into the Cu matrix particulates to a harmful extent that substantially degrades the conductivity of the Cu-Fe composite.

  10. Effects of annealing on antiwear and antibacteria behaviors of TaN-Cu nanocomposite thin films

    SciTech Connect (OSTI)

    Hsieh, J. H.; Cheng, M. K.; Chang, Y. K.; Li, C.; Chang, C. L.; Liu, P. C.

    2008-07-15

    TaN-Cu nanocomposite films were deposited by reactive cosputtering on Si and tool steel substrates. The films were then annealed using rapid thermal annealing (RTA) at 400 deg. C for 2, 4, and 8 min, respectively, to induce the nucleation and growth of Cu particles in TaN matrix and on film surface. Field emission scanning electron microscopy was applied to characterize Cu nanoparticles emerged on the surface of TaN-Cu thin films. The effects of annealing on the antiwear and antibacterial properties of these films were studied. The results reveal that annealing by RTA can cause Cu nanoparticles to form on the TaN surface. Consequently, the tribological behaviors, as well as the antibacterial behavior may vary depending on particle size, particle distribution, and total exposed Cu amount. For the samples with large Cu particles, the reduction of averaged friction and wear rate is obvious. Apparently, it is due to the smeared Cu particles adhered onto the wear tracks. This Cu layer may act as a solid lubricant. From the antibacterial testing results, it is found that both Cu particle size and total exposed Cu amount are critical in making short-term antibacterial effect. Overall, all the annealed TaN-Cu samples can reach >99% antibacterial efficiency in 24 h, with respect to uncoated Si substrate.

  11. Hydrogen isotope trapping in Al-Cu binary alloys

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Chao, Paul; Karnesky, Richard A.

    2016-01-01

    In this study, the trapping mechanisms for hydrogen isotopes in Al–X Cu (0.0 at. % < X < 3.5 at. %) alloys were investigated using thermal desorption spectroscopy (TDS), electrical conductivity, and differential scanning calorimetry. Constant heating rate TDS was used to determine microstructural trap energies and occupancies. In addition to the trapping states in pure Al reported in the literature (interstitial lattice sites, dislocations, and vacancies), a trap site due to Al–Cu intermetallic precipitates is observed. The binding energy of this precipitate trap is (18 ± 3) kJ•mol–1 (0.19 ± 0.03 eV). Typical occupancy of this trap is high;more » for Al–2.6 at. % Cu (a Cu composition comparable to that in AA2219) charged at 200 °C with 130 MPa D2 for 68 days, there is ca. there is 3.15×10–7 mol D bound to the precipitate trap per mol of Al, accounting for a third of the D in the charged sample.« less

  12. Local structure order in Pd??Cu?Si?? liquid

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Yue, G. Q.; Iowa State Univ., Ames, IA; Zhang, Y.; Sun, Y.; Shen, B.; Dong, F.; Wang, Z. Y.; Zhang, R. J.; Zheng, Y. X.; Kramer, M. J.; et al

    2015-02-05

    The short-range order (SRO) in Pd??Cu?Si?? liquid was studied by high energy x-ray diffraction and ab initio molecular dynamics (MD) simulations. The calculated pair correlation functions at different temperatures agree well with the experimental results. The partial pair correlation functions from ab intio MD simulations indicate that Si atoms prefer to be uniformly distributed while Cu atoms tend to aggregate. By performing structure analysis using Honeycutt-Andersen index, Voronoi tessellation, and atomic cluster alignment method, we show that the icosahedron and face-centered cubic SRO increase upon cooling. The dominant SRO is the Pd-centered Pd?Si? motif, namely the structure of which motifmoreis similar to the structure of Pd-centered clusters in the Pd?Si? crystal. The study further confirms the existence of trigonal prism capped with three half-octahedra that is reported as a structural unit in Pd-based amorphous alloys. The majority of Cu-centered clusters are icosahedra, suggesting that the presence of Cu is benefit to promote the glass forming ability.less

  13. Hydrogen isotope trapping in Al-Cu binary alloys

    SciTech Connect (OSTI)

    Chao, Paul; Karnesky, Richard A.

    2016-01-01

    In this study, the trapping mechanisms for hydrogen isotopes in Al–X Cu (0.0 at. % < X < 3.5 at. %) alloys were investigated using thermal desorption spectroscopy (TDS), electrical conductivity, and differential scanning calorimetry. Constant heating rate TDS was used to determine microstructural trap energies and occupancies. In addition to the trapping states in pure Al reported in the literature (interstitial lattice sites, dislocations, and vacancies), a trap site due to Al–Cu intermetallic precipitates is observed. The binding energy of this precipitate trap is (18 ± 3) kJ•mol–1 (0.19 ± 0.03 eV). Typical occupancy of this trap is high; for Al–2.6 at. % Cu (a Cu composition comparable to that in AA2219) charged at 200 °C with 130 MPa D2 for 68 days, there is ca. there is 3.15×10–7 mol D bound to the precipitate trap per mol of Al, accounting for a third of the D in the charged sample.

  14. An in-situ phosphorus source for the synthesis of Cu3P and the subsequent conversion to Cu3PS4 nanoparticle clusters

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Sheets, Erik J.; Stach, Eric A.; Yang, Wei -Chang; Balow, Robert B.; Wang, Yunjie; Walker, Bryce C.; Agrawal, Rakesh

    2015-09-20

    The search for alternative earth abundant semiconducting nanocrystals for sustainable energy applications has brought forth the need for nanoscale syntheses beyond bulk synthesis routes. Of particular interest are metal phosphides and derivative I-V-VI chalcogenides including copper phosphide (Cu3P) and copper thiophosphate (Cu3PS4). Herein, we report a one-pot, solution-based synthesis of Cu3P nanocrystals utilizing an in-situ phosphorus source: phosphorus pentasulfide (P2S5) in trioctylphosphine (TOP). By injecting this phosphorus source into a copper solution in oleylamine (OLA), uniform and size controlled Cu3P nanocrystals with a phosphorous-rich surface are synthesized. The subsequent reaction of the Cu3P nanocrystals with decomposing thiourea forms nanoscale Cu3PS4more » particles having p-type conductivity and an effective optical band gap of 2.36 eV.« less

  15. Shock response of He bubbles in single crystal Cu

    SciTech Connect (OSTI)

    Li, B.; Wang, L.; E, J. C.; Luo, S. N.; Ma, H. H.

    2014-12-07

    With large-scale molecular dynamics simulations, we investigate shock response of He nanobubbles in single crystal Cu. For sufficient bubble size or internal pressure, a prismatic dislocation loop may form around a bubble in unshocked Cu. The internal He pressure helps to stabilize the bubble against plastic deformation. However, the prismatic dislocation loops may partially heal but facilitate nucleation of new shear and prismatic dislocation loops. For strong shocks, the internal pressure also impedes internal jetting, while a bubble assists local melting; a high speed jet breaks a He bubble into pieces dispersed among Cu. Near-surface He bubbles may burst and form high velocity ejecta containing atoms and small fragments, while the ejecta velocities do not follow the three-dimensional Maxwell-Boltzmann distributions expected for thermal equilibrium. The biggest fragment size deceases with increasing shock strength. With a decrease in ligament thickness or an increase in He bubble size, the critical shock strength required for bubble bursting decreases, while the velocity range, space extension and average velocity component along the shock direction, increase. Small bubbles are more efficient in mass ejecting. Compared to voids and perfect single crystal Cu, He bubbles have pronounced effects on shock response including bubble/void collapse, Hugoniot elastic limit (HEL), deformation mechanisms, and surface jetting. HEL is the highest for perfect single crystal Cu with the same orientations, followed by He bubbles without pre-existing prismatic dislocation loops, and then voids. Complete void collapse and shear dislocations occur for embedded voids, as opposed to partial collapse, and shear and possibly prismatic dislocations for He bubbles. He bubbles lower the threshhold shock strength for ejecta formation, and increase ejecta velocity and ejected mass.

  16. NO Chemisorption on Cu/SSZ-13: a Comparative Study from Infrared Spectroscopy and DFT Calculations

    SciTech Connect (OSTI)

    Zhang, Renqin; McEwen, Jean-Sabin; Kollar, Marton; Gao, Feng; Wang, Yilin; Szanyi, Janos; Peden, Charles HF

    2014-11-07

    The locations and energies of Cu ions in a Cu/SSZ-13 zeolite catalyst were investigated by density functional theory (DFT) calculations. For 'naked' Cu2+ ions (i.e., Cu2+ ions with no ligands in their coordination spheres other than zeolite lattice oxygen atoms), the more energetically favorable sites are within a 6-membered ring. However, with the presence of various adsorbates, the energy difference between 6- and 8-membered ring locations greatly diminishes. Specifically, Cu2+ ions are substantially stabilized by -OH ligands (as [CuII(OH)]+), making the extra-framework sites in an 8-membered ring energetically more favorable than 6-membered ring sites. Under fully dehydrated high vacuum conditions with different Si/Al and Cu/Al ratios, three chemisorbed NO species coexist upon exposure of NO to Cu/SSZ-13: NO+, Cu2+-NO and Cu+-NO. The relative signal intensities for these bands vary greatly with Si/Al ratios. The vibrational frequency of chemisorbed NO was found to be very sensitive to the location of Cu2+ ions. On the one hand, with the aid from DFT calculations, the nature for these vibrations can be assigned in detail. On the other hand, the relative intensities for various Cu2+-NO species provide a good measure of the nature of Cu2+ ions as functions of Si/Al and Cu/Al ratios and the presence of humidity. These new findings cast doubt on the generally accepted proposal that only Cu2+ ions located in 6-membered rings are catalytically active for NH3-SCR.

  17. Influence of Al/CuO reactive multilayer films additives on exploding foil initiator

    SciTech Connect (OSTI)

    Zhou Xiang; Shen Ruiqi; Ye Yinghua; Zhu Peng; Hu Yan; Wu Lizhi

    2011-11-01

    An investigation on the influence of Al/CuO reactive multilayer films (RMFs) additives on exploding foil initiator was performed in this paper. Cu film and Cu/Al/CuO RMFs were produced by using standard microsystem technology and RF magnetron sputtering technology, respectively. Scanning electron microscopy characterization revealed the distinct layer structure of the as-deposited Al/CuO RMFs. Differential scanning calorimetry was employed to ascertain the amount of heat released in the thermite reaction between Al films and CuO films, which was found to be 2024 J/g. Electrical explosion tests showed that 600 V was the most matching voltage for our set of apparatus. The explosion process of two types of films was observed by high speed camera and revealed that compared with Cu film, an extra distinct combustion phenomenon was detected with large numbers of product particles fiercely ejected to a distance of about six millimeters for Cu/Al/CuO RMFs. By using the atomic emission spectroscopy double line technique, the reaction temperature was determined to be about 6000-7000 K and 8000-9000 K for Cu film and Cu/Al/CuO RMFs, respectively. The piezoelectricity of polyvinylidene fluoride film was employed to measure the average velocity of the slapper accelerated by the explosion of the films. The average velocities of the slappers were calculated to be 381 m/s and 326 m/s for Cu film and Cu/Al/CuO RMFs, respectively, and some probable reasons were discussed with a few suggestions put forward for further work.

  18. Direct Epoxidation of Propylene over Stabilized Cu+ Surface Sites on Ti Modified Cu2O

    SciTech Connect (OSTI)

    Yang, X.; Kattel, S.; Xiong, K.; Mudiyanselage, K.; Rykov, S.; Senanayake, S. D.; Rodriguez, J. A.; Liu, P.; Stacchiola, D. J.; Chen, J. G.

    2015-07-17

    Direct propylene epoxidation by O2 is a challenging reaction because of the strong tendency for complete combustion. Results from the current study demonstrate the feasibility to tune the epoxidation selectivity by generating highly dispersed and stabilized Cu+ active sites in a TiCuOx mixed oxide. The TiCuOx surface anchors the key surface intermediate, oxametallacycle, leading to higher selectivity for epoxidation of propylene.

  19. Thermochemical and kinetic aspects of the sulfurization of Cu-Sb and Cu-Bi thin films

    SciTech Connect (OSTI)

    Colombara, Diego; Peter, Laurence M.; Rogers, Keith D.; Hutchings, Kyle

    2012-02-15

    CuSbS{sub 2} and Cu{sub 3}BiS{sub 3} are being investigated as part of a search for new absorber materials for photovoltaic devices. Thin films of these chalcogenides were produced by conversion of stacked and co-electroplated metal precursor layers in the presence of elemental sulfur vapour. Ex-situ XRD and SEM/EDS analyses of the processed samples were employed to study the reaction sequence with the aim of achieving compact layer morphologies. A new 'Time-Temperature-Reaction' (TTR) diagram and modified Pilling-Bedworth coefficients have been introduced for the description and interpretation of the reaction kinetics. For equal processing times, the minimum temperature required for CuSbS{sub 2} to appear is substantially lower than for Cu{sub 3}BiS{sub 3}, suggesting that interdiffusion across the interfaces between the binary sulfides is a key step in the formation of the ternary compounds. The effects of the heating rate and sulfur partial pressure on the phase evolution as well as the potential losses of Sb and Bi during the processes have been investigated experimentally and the results related to the equilibrium pressure diagrams obtained via thermochemical computation. - Graphical Abstract: Example of 3D plot showing the equilibrium pressure surfaces of species potentially escaping from chalcogenide films as a function of temperature and sulfur partial pressure. Bi{sub (g)}, Bi{sub 2(g)}, and BiS{sub (g)} are the gaseous species in equilibrium with solid Bi{sub 2}S{sub 3(s)} considered in this specific example. The pressure threshold plane corresponds to the pressure limit above which the elemental losses from 1 {mu}m thick films exceeds 10% of the original content per cm{sup 2} area of film and dm{sup 3} capacity of sulfurization furnace under static atmosphere conditions. The sulfurization temperature/sulfur partial pressure boundaries required to minimise the elemental losses below a given value can be easily read from the 2D projection of the intersection curves into the T-p{sub S2} plane. Highlights: Black-Right-Pointing-Triangle Sulfurization of Sb-Cu and Bi-Cu metal precursors for thin film PV applications. Black-Right-Pointing-Triangle Kinetics shows the rate determining step to be the interdiffusion of binary sulfides. Black-Right-Pointing-Triangle Phase evolution is consistent with Pilling-Bedworth coefficients of Cu, Sb and Bi. Black-Right-Pointing-Triangle Elemental losses can be minimised via the use of equilibrium pressure diagrams.

  20. Nanoporous Cu-C composites based on carbon-nanotube aerogels (Journal

    Office of Scientific and Technical Information (OSTI)

    Article) | SciTech Connect Nanoporous Cu-C composites based on carbon-nanotube aerogels Citation Details In-Document Search Title: Nanoporous Cu-C composites based on carbon-nanotube aerogels Current synthesis methods of nanoporous Cu-C composites offer limited control of the material composition, structure, and properties, particularly for large Cu loadings of ≳20 wt%. Here, we describe two related approaches to realize novel nanoporous Cu-C composites based on the templating of recently

  1. Methods for producing Cu-67 radioisotope with use of a ceramic capsule for medical applications

    DOE Patents [OSTI]

    Ehst, David A.; Willit, James L.

    2016-04-12

    The present invention provides a method for producing Cu67 radioisotope suitable for use in medical applications. The method comprises irradiating a metallic zinc-68 (Zn68) target within a sealed ceramic capsule with a high energy gamma ray beam. After irradiation, the Cu67 is isolated from the Zn68 by any suitable method (e.g. chemical and or physical separation). In a preferred embodiment, the Cu67 is isolated by sublimation of the zinc in a ceramic sublimation tube to afford a copper residue containing Cu67. The Cu67 can be further purified by chemical means.

  2. Long-term leaching test of incinerator bottom ash: Evaluation of Cu partition

    SciTech Connect (OSTI)

    Lin, Cheng-Fang Wu, Chung-Hsin; Liu, Yen-Chiun

    2007-07-01

    Two types of leaching tests were performed on the bottom ash from municipal solid waste incinerators. A short-term batch test specified by the America Nuclear Society (ANS) and long-term column tests with acetic acid (pH 5.2) as leaching solution were used to evaluate copper leachability. The Cu leaching after the 5-d ANS test is about 1% of the original Cu content of 5300 mg/kg. Upon addition of a stabilizing agent, the Cu leaching quantity is reduced; the extent of reduction depends on the type of chemical used (phosphate, carbonate and sulfide). The 1.6% Na{sub 2}S addition showed negligible Cu leaching, and Na{sub 2}S was, therefore, used in subsequent column tests. The 30-d column test indicates a steady increase of Cu leaching amount with time and reaches about 1.5% of the original Cu content after 30 d. A 180-d column test further increased the Cu leaching to about 5.1% of the original Cu content, whereas no appreciable Cu leaching was found with the addition of 1.6% Na{sub 2}S. A sequential extraction was conducted on the raw ash, ash with the addition of Na{sub 2}S and the residue ash after 30 d of operation to characterize Cu affinity for different solid fractions. The data were used to evaluate the fate of Cu through these interactions.

  3. Effect of CNTs dispersion on the thermal and mechanical properties of Cu/CNTs nanocomposites

    SciTech Connect (OSTI)

    Muhsan, Ali Samer E-mail: faizahmad@petronas.com.my; Ahmad, Faiz E-mail: faizahmad@petronas.com.my; Yusoff, Puteri Sri Melor Megat Bt; Mohamed, Norani M.; Raza, M. Rafi

    2014-10-24

    Modified technique of metal injection molding (MIM) was used to fabricate multiwalled carbon nanotube (CNT) reinforced Cu nanocomposites. The effect of adding different amount of CNTs (0-10 vol.%) on the thermal and mechanical behaviour of the fabricated nanocomposites is presented. Scanning electron microscope analysis revealed homogenous dispersion of CNTs in Cu matrices at different CNTs contents. The experimentally measured thermal conductivities of Cu/CNTs nanocomposites showed extraordinary increase (76% higher than pure sintered Cu) with addition of 10 vol.% CNTs. As compared to the pure sintered Cu, increase in modulus of elasticity (Young's modulus) of Cu/CNTs nanocomposites sintered at 1050°C for 2.5 h was measured to be 48%. However, in case of 7.5 vol.% CNTs, Young's modulus was increased significantly about 51% compared to that of pure sintered Cu.

  4. Utility of reactively sputtered CuN{sub x} films in spintronics devices

    SciTech Connect (OSTI)

    Fang Yeyu; Persson, J.; Zha, C.; Willman, J.; Miller, Casey W.; Aakerman, Johan

    2012-04-01

    We have studied nitrified copper (CuN{sub x}) thin films grown by reactive sputtering in the context of spintronic devices. The Ar-to-N{sub 2} flow ratio enables tunability of the electrical resistivity and surface roughness of the CuN{sub x} films, with the former increasing to nearly 20 times that of Cu, and the latter reduced to the atomic scale. Incorporating this into a Ta/CuN{sub x}/Ta seed stack for spin valves improves the current-in-plane (CIP) magnetoresistance; maximum magnetoresistance results with CuN{sub x} seed layer and Cu interlayer. Finally, finite element modeling results are presented that suggest the use of CuN{sub x} in nanocontact spin torque oscillators can enhance current densities by limiting the current spread through the device. This may positively impact threshold currents, power requirements, and device reliability.

  5. Comparative Study of the Defect Point Physics and Luminescence of the Kesterites Cu2ZnSnS4 and Cu2ZnSnSe4 and Chalcopyrite Cu(In,Ga)Se2: Preprint

    SciTech Connect (OSTI)

    Romero, M. J.; Repins, I.; Teeter, G.; Contreras, M.; Al-Jassim, M.; Noufi, R.

    2012-08-01

    In this contribution, we present a comparative study of the luminescence of the kesterites Cu2ZnSnS4 (CZTS) and Cu2ZnSnSe4 (CZTSe) and their related chalcopyrite Cu(In,Ga)Se2 (CIGSe). Luminescence spectroscopy suggests that the electronic properties of Zn-rich, Cu-poor kesterites (both CZTS and CZTSe) and Cu-poor CIGSe are dictated by fluctuations of the electrostatic and chemical potentials. The large redshift in the luminescence of grain boundaries in CIGSe, associated with the formation of a neutral barrier is clearly observed in CZTSe, and, to some extent, in CZTS. Kesterites can therefore replicate the fundamental electronic properties of CIGSe.

  6. Solidification behavior and structure of Al-Cu alloy welds

    SciTech Connect (OSTI)

    Brooks, J.A.; Li, M.; Yang, N.C.Y.

    1997-09-01

    The microsegregation behavior of electron beam (EB) and gas tungsten arc (GTA) welds of Al-Cu alloys covering a range from 0.19 to 7.74 wt% Cu were characterized for dendrite core concentrations and fraction eutectic solidification. Although a single weld speed of 12.7 mm/sec was used, some differences were observed in the segregation behavior of the two weld types. The microsegregation behavior was also modeled using a finite differences technique considering dendrite tip and eutectic undercooling and solid state diffusion. Fairly good agreement was observed between measured and calculated segregation behavior although differences between the two weld types could not be completely accounted for. The concept of dendrite tip undercooling was used to explain the formation of a single through thickness centerline grain in the higher alloy content GTA welds.

  7. Intermixing in Cu/Ni multilayers induced by cold rolling

    SciTech Connect (OSTI)

    Wang, Z.; Perepezko, J. H.; Larson, D.; Reinhard, D.

    2015-04-28

    Repeated cold rolling was performed on multilayers of Cu60/Ni40 and Cu40/Ni60 foil arrays to study the details of driven atomic scale interfacial mixing. With increasing deformation, there is a significant layer refinement down to the nm level that leads to the formation of a solid solution phase from the elemental end members. Intriguingly, the composition of the solid solution is revealed by an oscillation in the composition profile across the multilayers, which is different from the smoothly varying profile due to thermally activated diffusion. During the reaction, Cu mixed into Ni preferentially compared to Ni mixing into Cu, which is also in contrast to the thermal diffusion behavior. This is confirmed by observations from X-ray diffraction, electron energy loss spectrum and atom probe tomography. The diffusion coefficient induced by cold rolling is estimated as 1.7 × 10{sup −17} m{sup 2}/s, which cannot be attributed to any thermal effect. The effective temperature due to the deformation induced mixing is estimated as 1093 K and an intrinsic diffusivity d{sub b}, which quantifies the tendency towards equilibrium in the absence of thermal diffusion, is estimated as 6.38 × 10{sup −18} m{sup 2}/s. The fraction of the solid solution phase formed is illustrated by examining the layer thickness distribution and is described by using an error function representation. The evolution of mixing in the solid solution phase is described by a simplified sinusoid model, in which the amplitude decays with increased deformation level. The promoted diffusion coefficient could be related to the effective temperature concept, but the establishment of an oscillation in the composition profile is a characteristic behavior that develops due to deformation.

  8. CuC1 thermochemical cycle for hydrogen production

    DOE Patents [OSTI]

    Fan, Qinbai; Liu, Renxuan

    2012-01-03

    An electrochemical cell for producing copper having a dense graphite anode electrode and a dense graphite cathode electrode disposed in a CuCl solution. An anion exchange membrane made of poly(ethylene vinyl alcohol) and polyethylenimine cross-linked with a cross-linking agent selected from the group consisting of acetone, formaldehyde, glyoxal, glutaraldehyde, and mixtures thereof is disposed between the two electrodes.

  9. Impedance analysis of MnCoCuO NTC ceramic

    SciTech Connect (OSTI)

    Song, S.G. . E-mail: song-ph0@wpmail.paisley.ac.uk; Ling, Z.; Placido, F.

    2005-07-12

    Impedance spectroscopy is often used to analyse the electrical properties of ceramic materials having high-resistive grain boundaries, such as ZnO and SrTiO{sub 3}. Fewer attempts have been made at using this technique for the analysis of inhomogeneous electronic ceramics consisting of grains with differing composition, such as those occurring in negative temperature coefficient (NTC) thermistors. In this study, we have attempted to adopt ac impedance spectroscopy together with other techniques to analyse an NTC thermistor ceramic material. An Mn, Co and Cu multielements transition metal oxide (MnCoCuO) ceramic was prepared by using homogeneous precipitation employing oxalic acid. This material displayed a typical NTC effect, showing an electrical resistance decrease with temperature when dc electrical measurement was performed. The ac impedance spectroscopy analysis showed that there were two peaks in impedance and conductance versus frequency plot. By using an alternative representation of impedance spectra Z'/f versus Z', three distinct relaxation frequency ranges were identified. They are believed to originate, respectively, from the electrode, phase 1 (rich-Cu phase) and phase 2 (poor-Cu phase) grains existing in this ceramic. SEM observation and EDX analysis clearly showed existence of two distinct phase grains. The resistance values were derived from phases 1 and 2 grains based on ac impedance data. The sum of the resistance values was in good agreement with that from dc measurement in the temperature range of 30-95 deg. C. The material constant, B, for the two phases was also calculated, giving 3100 and 3600 K for phases 1 and 2, respectively.

  10. Synthesis of BiPbSrCaCuO superconductor

    DOE Patents [OSTI]

    Hults, W.L.; Kubat-Martin, K.A.; Salazar, K.V.; Phillips, D.S.; Peterson, D.E.

    1994-04-05

    A process and a precursor composition for preparing a lead-doped bismuth-strontium-calcium-copper oxide superconductor of the formula Bi[sub a]Pb[sub b]Sr[sub c]Ca[sub d]Cu[sub e]O[sub f] wherein a is from about 1.7 to about 1.9, b is from about 0.3 to about 0.45, c is from about 1.6 to about 2.2, d is from about 1.6 to about 2.2, e is from about 2.97 to about 3.2 and f is 10[+-]z by reacting a mixture of Bi[sub 4]Sr[sub 3]Ca[sub 3]Cu[sub 4]O[sub 16[+-]z], an alkaline earth metal cuprate, e.g., Sr[sub 9]Ca[sub 5]Cu[sub 24]O[sub 41], and an alkaline earth metal plumbate, e.g., Ca[sub 2[minus]x]Sr[sub x]PbO[sub 4] wherein x is about 0.5, is disclosed.

  11. Synthesis of BiPbSrCaCuO superconductor

    DOE Patents [OSTI]

    Hults, William L.; Kubat-Martin, Kimberly A.; Salazar, Kenneth V.; Phillips, David S.; Peterson, Dean E.

    1994-01-01

    A process and a precursor composition for preparing a lead-doped bismuth-strontium-calcium-copper oxide superconductor of the formula Bi.sub.a Pb.sub.b Sr.sub.c Ca.sub.d Cu.sub.e O.sub.f wherein a is from about 1.7 to about 1.9, b is from about 0.3 to about 0.45, c is from about 1.6 to about 2.2, d is from about 1.6 to about 2.2, e is from about 2.97 to about 3.2 and f is 10.+-.z by reacting a mixture of Bi.sub.4 Sr.sub.3 Ca.sub.3 Cu.sub.4 O.sub.16.+-.z, an alkaline earth metal cuprate, e.g., Sr.sub.9 Ca.sub.5 Cu.sub.24 O.sub.41, and an alkaline earth metal plumbate, e.g., Ca.sub.2-x Sr.sub.x PbO.sub.4 wherein x is about 0.5, is disclosed.

  12. Effects of Cu Diffusion from ZnTe:Cu/Ti Contacts on Carrier Lifetime of CdS/CdTe Thin Film Solar Cells: Preprint

    SciTech Connect (OSTI)

    Gessert, T. A.; Metzger, W. K.; Asher, S. E.; Young, M. R.; Johnston, S.; Dhere, R. G.; Duda, A.

    2008-05-01

    We study the performance of CdS/CdTe thin film PV devices processed with a ZnTe:Cu/Ti contact to investigate how carrier lifetime in the CdTe layer is affected by Cu diffusion from the contact.

  13. Complex catalytic behaviors of CuTiOx mixed-oxide during CO oxidation

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Kim, Hyun You; Liu, Ping

    2015-09-21

    Mixed metal oxides have attracted considerable attention in heterogeneous catalysis due to the unique stability, reactivity, and selectivity. Here, the activity and stability of the CuTiOx monolayer film supported on Cu(111), CuTiOx/Cu(111), during CO oxidation was explored using density functional theory (DFT). The unique structural frame of CuTiOx is able to stabilize and isolate a single Cu+ site on the terrace, which is previously proposed active for CO oxidation. Furthermore, it is not the case, where the reaction via both the Langmuir–Hinshelwood (LH) and the Mars-van Krevelen (M-vK) mechanisms are hindered on such single Cu+ site. Upon the formation ofmore » step-edges, the synergy among Cuδ+ sites, TiOx matrix, and Cu(111) is able to catalyze the reaction well. Depending on temperatures and partial pressure of CO and O2, the surface structure varies, which determines the dominant mechanism. In accordance with our results, the Cuδ+ ion alone does not work well for CO oxidation in the form of single sites, while the synergy among multiple active sites is necessary to facilitate the reaction.« less

  14. Systematic study of azimuthal anisotropy in Cu + Cu and Au + Au collisions at √sNN = 62.4 and 200 GeV

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Adare, A.

    2015-09-23

    We have studied the dependence of azimuthal anisotropy v2 for inclusive and identified charged hadrons in Au+Au and Cu+Cu collisions on collision energy, species, and centrality. The values of v2 as a function of transverse momentum pT and centrality in Au+Au collisions at √sNN=200 and 62.4 GeV are the same within uncertainties. However, in Cu+Cu collisions we observe a decrease in v2 values as the collision energy is reduced from 200 to 62.4 GeV. The decrease is larger in the more peripheral collisions. By examining both Au+Au and Cu+Cu collisions we find that v2 depends both on eccentricity and themore » number of participants, Npart. We observe that v2 divided by eccentricity (ε) monotonically increases with Npart and scales as N1/3part. Thus, the Cu+Cu data at 62.4 GeV falls below the other scaled v2 data. For identified hadrons, v2 divided by the number of constituent quarks nq is independent of hadron species as a function of transverse kinetic energy KET=mT–m between 0.1T/nq<1 GeV. Combining all of the above scaling and normalizations, we observe a near-universal scaling, with the exception of the Cu+Cu data at 62.4 GeV, of v2/(nq∙ε∙N1/3part) vs KET/nq for all measured particles.« less

  15. Systematic study of azimuthal anisotropy in Cu + Cu and Au + Au collisions at √sNN = 62.4 and 200 GeV

    SciTech Connect (OSTI)

    Adare, A.

    2015-09-23

    We have studied the dependence of azimuthal anisotropy v2 for inclusive and identified charged hadrons in Au+Au and Cu+Cu collisions on collision energy, species, and centrality. The values of v2 as a function of transverse momentum pT and centrality in Au+Au collisions at √sNN=200 and 62.4 GeV are the same within uncertainties. However, in Cu+Cu collisions we observe a decrease in v2 values as the collision energy is reduced from 200 to 62.4 GeV. The decrease is larger in the more peripheral collisions. By examining both Au+Au and Cu+Cu collisions we find that v2 depends both on eccentricity and the number of participants, Npart. We observe that v2 divided by eccentricity (ε) monotonically increases with Npart and scales as N1/3part. Thus, the Cu+Cu data at 62.4 GeV falls below the other scaled v2 data. For identified hadrons, v2 divided by the number of constituent quarks nq is independent of hadron species as a function of transverse kinetic energy KET=mT–m between 0.1T/nq<1 GeV. Combining all of the above scaling and normalizations, we observe a near-universal scaling, with the exception of the Cu+Cu data at 62.4 GeV, of v2/(nq∙ε∙N1/3part) vs KET/nq for all measured particles.

  16. Oxygen-induced Y surface segregation in a CuPdY ternary alloy

    SciTech Connect (OSTI)

    Tafen, D. N.; Miller, J. B.; Dogan, O. N.; Baltrus, J. P.; Kondratyuk, P.

    2013-01-01

    We present a comprehensive theoretical and experimental study of the segregation behavior of the ternary alloy CuPdY in vacuum (i.e., the clean surface) and in the presence of oxygen. Theoretical prediction shows that for clean surface, yttrium will substitute first for Cu and then for Pd at the subsurface lattice site before segregating to the surface where it substitutes for Cu. XRD characterization of the surface of CuPdY indicates the presence of two major phases, B2 CuPd and Pd{sub 3}Y. In the presence of adsorbed oxygen, theory predicts that Y preferentially occupies surface sites due to its stronger oxygen affinity compared to Cu and Pd. XPS experiments confirm the computational results in the adsorbed oxygen case, showing that surface segregation of yttrium is induced by the formation of Y-oxides at the top-surface of the alloy.

  17. Adsorbate-driven morphological changes on Cu(111) nano-pits

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Mudiyanselage, K.; Xu, F.; Hoffmann, F. M.; Hrbek, J.; Waluyo, I.; Boscoboinik, J. A.; Stacchiola, D. J.

    2014-12-09

    Adsorbate-driven morphological changes of pitted-Cu(111) surfaces have been investigated following the adsorption and desorption of CO and H. The morphology of the pitted-Cu(111) surfaces, prepared by Ar+ sputtering, exposed a few atomic layers deep nested hexagonal pits of diameters from 8 to 38 nm with steep step bundles. The roughness of pitted-Cu(111) surfaces can be healed by heating to 450-500 K in vacuum. Adsorption of CO on the pitted-Cu(111) surface leads to two infrared peaks at 2089-2090 and 2101-2105 cm-1 for CO adsorbed on under-coordinated sites in addition to the peak at 2071 cm-1 for CO adsorbed on atop sitesmore » of the close-packed Cu(111) surface. CO adsorbed on under-coordinated sites is thermally more stable than that of atop Cu(111) sites. Annealing of the CO-covered surface from 100 to 300 K leads to minor changes of the surface morphology. In contrast, annealing of a H covered surface to 300 K creates a smooth Cu(111) surface as deduced from infrared data of adsorbed CO and scanning tunnelling microscopy (STM) imaging. The observation of significant adsorbate-driven morphological changes with H is attributed to its stronger modification of the Cu(111) surface by the formation of a sub-surface hydride with a hexagonal structure, which relaxes into the healed Cu(111) surface upon hydrogen desorption. These morphological changes occur ~150 K below the temperature required for healing of the pitted-Cu(111) surface by annealing in vacuum. In contrast, the adsorption of CO, which only interacts with the top-most Cu layer and desorbs by 160 K, does not significantly change the morphology of the pitted-Cu(111) surface.« less

  18. Adsorbate-driven morphological changes on Cu(111) nano-pits

    SciTech Connect (OSTI)

    Mudiyanselage, K.; Xu, F.; Hoffmann, F. M.; Hrbek, J.; Waluyo, I.; Boscoboinik, J. A.; Stacchiola, D. J.

    2014-12-09

    Adsorbate-driven morphological changes of pitted-Cu(111) surfaces have been investigated following the adsorption and desorption of CO and H. The morphology of the pitted-Cu(111) surfaces, prepared by Ar+ sputtering, exposed a few atomic layers deep nested hexagonal pits of diameters from 8 to 38 nm with steep step bundles. The roughness of pitted-Cu(111) surfaces can be healed by heating to 450-500 K in vacuum. Adsorption of CO on the pitted-Cu(111) surface leads to two infrared peaks at 2089-2090 and 2101-2105 cm-1 for CO adsorbed on under-coordinated sites in addition to the peak at 2071 cm-1 for CO adsorbed on atop sites of the close-packed Cu(111) surface. CO adsorbed on under-coordinated sites is thermally more stable than that of atop Cu(111) sites. Annealing of the CO-covered surface from 100 to 300 K leads to minor changes of the surface morphology. In contrast, annealing of a H covered surface to 300 K creates a smooth Cu(111) surface as deduced from infrared data of adsorbed CO and scanning tunnelling microscopy (STM) imaging. The observation of significant adsorbate-driven morphological changes with H is attributed to its stronger modification of the Cu(111) surface by the formation of a sub-surface hydride with a hexagonal structure, which relaxes into the healed Cu(111) surface upon hydrogen desorption. These morphological changes occur ~150 K below the temperature required for healing of the pitted-Cu(111) surface by annealing in vacuum. In contrast, the adsorption of CO, which only interacts with the top-most Cu layer and desorbs by 160 K, does not significantly change the morphology of the pitted-Cu(111) surface.

  19. Adsorbate-driven morphological changes on Cu(111) nano-pits

    SciTech Connect (OSTI)

    Mudiyanselage, K.; Xu, F.; Hoffmann, F. M.; Hrbek, J.; Waluyo, I.; Boscoboinik, J. A.; Stacchiola, D. J.

    2015-01-01

    Adsorbate-driven morphological changes of pitted-Cu(111) surfaces have been investigated following the adsorption and desorption of CO and H. The morphology of the pitted-Cu(111) surfaces, prepared by Ar+ sputtering, exposed a few atomic layers deep nested hexagonal pits of diameters from 8 to 38 nm with steep step bundles. The roughness of pitted-Cu(111) surfaces can be healed by heating to 450-500 K in vacuum. Adsorption of CO on the pitted-Cu(111) surface leads to two infrared peaks at 2089-2090 and 2101-2105 cm-1 for CO adsorbed on under-coordinated sites in addition to the peak at 2071 cm-1 for CO adsorbed on atop sites of the close-packed Cu(111) surface. CO adsorbed on under-coordinated sites is thermally more stable than that of atop Cu(111) sites. Annealing of the CO-covered surface from 100 to 300 K leads to minor changes of the surface morphology. In contrast, annealing of a H covered surface to 300 K creates a smooth Cu(111) surface as deduced from infrared data of adsorbed CO and scanning tunnelling microscopy (STM) imaging. The observation of significant adsorbate-driven morphological changes with H is attributed to its stronger modification of the Cu(111) surface by the formation of a sub-surface hydride with a hexagonal structure, which relaxes into the healed Cu(111) surface upon hydrogen desorption. These morphological changes occur ~150 K below the temperature required for healing of the pitted-Cu(111) surface by annealing in vacuum. In contrast, the adsorption of CO, which only interacts with the top-most Cu layer and desorbs by 160 K, does not significantly change the morphology of the pitted-Cu(111) surface.

  20. Deactivation Mechanism of Cu/Zeolite SCR Catalyst Due to Reductive

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

    Hydrothermal Aging | Department of Energy Better control for preventing catalyst deactivation resulted from study of and proposed mechanism for deactivation of Cu/zeolite under rich conditions. PDF icon deer08_huang.pdf More Documents & Publications Understanding the Deactivation Mechanisms of Cu/Zeolite SCR Catalysts in Diesel Application Investigation of Sulfur Deactivation on Cu/Zeolite SCR Catalysts in Diesel Application Deactivation Mechanisms of Base Metal/Zeolite Urea Selective

  1. Method of fabricating high-efficiency Cu(In,Ga)(Se,S){sub 2} thin films for solar cells

    DOE Patents [OSTI]

    Noufi, R.; Gabor, A.M.; Tuttle, J.R.; Tennant, A.L.; Contreras, M.A.; Albin, D.S.; Carapella, J.J.

    1995-08-15

    A process for producing a slightly Cu-poor thin film of Cu(In,Ga)(Se,S){sub 2} comprises depositing a first layer of (In,Ga){sub x} (Se,S){sub y} followed by depositing just enough Cu+(Se,S) or Cu{sub x} (Se,S) to produce the desired slightly Cu-poor material. In a variation, most, but not all, (about 90 to 99%) of the (In,Ga){sub x} (Se,S){sub y} is deposited first, followed by deposition of all the Cu+(Se,S) or Cu{sub x} (Se,S) to go near stoichiometric, possibly or even preferably slightly Cu-rich, and then in turn followed by deposition of the remainder (about 1 to 10%) of the (In,Ga){sub x} (Se,S){sub y} to end with a slightly Cu-poor composition. In yet another variation, a small portion (about 1 to 10%) of the (In,Ga){sub x} (Se,S){sub y} is first deposited as a seed layer, followed by deposition of all of the Cu+(Se,S) or Cu{sub x} (Se,S) to make a very Cu-rich mixture, and then followed deposition of the remainder of the (In,Ga){sub x} (Se,S){sub y} to go slightly Cu-poor in the final Cu(In,Ga)(Se,S){sub 2} thin film. 5 figs.

  2. Method of fabricating high-efficiency Cu(In,Ga)(SeS).sub.2 thin films for solar cells

    DOE Patents [OSTI]

    Noufi, Rommel; Gabor, Andrew M.; Tuttle, John R.; Tennant, Andrew L.; Contreras, Miguel A.; Albin, David S.; Carapella, Jeffrey J.

    1995-01-01

    A process for producing a slightly Cu-poor thin film of Cu(In,Ga)(Se,S).sub.2 comprises depositing a first layer of (In,Ga).sub.x (Se,S).sub.y followed by depositing just enough Cu+(Se,S) or Cu.sub.x (Se,S) to produce the desired slightly Cu-poor material. In a variation, most, but not all, (about 90 to 99%) of the (In,Ga).sub.x (Se,S).sub.y is deposited first, followed by deposition of all the Cu+(Se,S) or Cu.sub.x (Se,S) to go near stoichiometric, possibly or even preferably slightly Cu-rich, and then in turn followed by deposition of the remainder (about 1 to 10%) of the (In,Ga).sub.x (Se,S).sub.y to end with a slightly Cu-poor composition. In yet another variation, a small portion (about 1 to 10%) of the (In,Ga).sub.x (Se,S).sub.y is first deposited as a seed layer, followed by deposition of all of the Cu+(Se,S) or Cu.sub.x (Se,S) to make a very Cu-rich mixture, and then followed deposition of the remainder of the (In,Ga).sub.x (Se,S).sub.y to go slightly Cu-poor in the final Cu(In,Ga)(Se,S).sub.2 thin film.

  3. Method of forming superconducting Tl-Ba-Ca-Cu-O films

    DOE Patents [OSTI]

    Wessels, Bruce W.; Marks, Tobin J.; Richeson, Darrin S.; Tonge, Lauren M.; Zhang, Jiming

    1993-01-01

    A method of forming a superconducting Tl-Ba-Ca-Cu-O film is disclosed, which comprises depositing a Ba-Ca-Cu-O film on a substrate by MOCVD, annealing the deposited film and heat-treating the annealed film in a closed circular vessel with TlBa.sub.2 Ca.sub.2 Cu.sub.3 O.sub.x and cooling to form said superconducting film of TlO.sub.m Ba.sub.2 Ca.sub.n-1 Cu.sub.n O.sub.2n+2, wherein m=1,2 and n=1,2,3.

  4. Earth-Abundant Cu-based Chalcogenide Materials as Photovoltaic Absorbers

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

    Photovoltaic (PV) conversion is demonstrated for the first time in Cu 3 PSe 4 , a member of the Cu 3 MCh 4 (Ch = S,Se; M = P, As, Sb) materials family, identified using the inverse design method as absorber candidates that have stronger solar absorption than CuInSe 2 . Significance and Impact The Cu 3 MCh 4 materials family provides a unique opportunity for addressing needs in single- and multijunction cells for both PV and photo-electrochemical water splitting with a single, inexpensive set of

  5. Effects of Cr/Zn Substitutions on Dielectric Properties of CaCu...

    Office of Scientific and Technical Information (OSTI)

    Our results indicate that Cu and Ti sites play an important role in the formation of ... Country of Publication: United States Language: English Subject: 36 MATERIALS SCIENCE; ...

  6. Electrical properties of single CuO nanowires for device fabrication: Diodes and field effect transistors

    SciTech Connect (OSTI)

    Florica, Camelia; Costas, Andreea; Boni, Andra Georgia; Negrea, Raluca; Preda, Nicoleta E-mail: encu@infim.ro; Pintilie, Lucian; Enculescu, Ionut E-mail: encu@infim.ro; Ion, Lucian

    2015-06-01

    High aspect ratio CuO nanowires are synthesized by a simple and scalable method, thermal oxidation in air. The structural, morphological, optical, and electrical properties of the semiconducting nanowires were studied. Au-Ti/CuO nanowire and Pt/CuO nanowire electrical contacts were investigated. A dominant Schottky mechanism was evidenced in the Au-Ti/CuO nanowire junction and an ohmic behavior was observed for the Pt/CuO nanowire junction. The Pt/CuO nanowire/Pt structure allows the measurements of the intrinsic transport properties of the single CuO nanowires. It was found that an activation mechanism describes the behavior at higher temperatures, while a nearest neighbor hopping transport mechanism is characteristic at low temperatures. This was also confirmed by four-probe resistivity measurements on the single CuO nanowires. By changing the metal/semiconductor interface, devices such as Schottky diodes and field effect transistors based on single CuO p-type nanowire semiconductor channel are obtained. These devices are suitable for being used in various electronic circuits where their size related properties can be exploited.

  7. Structural, optical and ethanol sensing properties of Cu-doped SnO{sub 2} nanowires

    SciTech Connect (OSTI)

    Johari, Anima Sharma, Manish; Johari, Anoopshi; Bhatnagar, M. C.

    2014-04-24

    In present work, one-dimensional nanostructure of Cu-doped Tin oxide (SnO{sub 2}) was synthesized by using thermal evaporation method in a tubular furnace under Nitrogen (N{sub 2}) ambience. The growth was carried out at atmospheric pressure. SEM and TEM images reveal the growth of wire-like nanostructures of Cu-doped SnO{sub 2} on Si substrate. The XRD analysis confirms that the synthesized SnO{sub 2} nanowires have tetragonal rutile structure with polycrystalline nature and X-ray diffraction pattern also showed that Cu gets incorporated into the SnO{sub 2} lattice. EDX spectra confirm the doping of Cu into SnO{sub 2} nanowires and atomic fraction of Cu in nanowires is ∼ 0.5 at%. The Vapor Liquid Solid (VLS) growth mechanism for Cu-doped SnO{sub 2} nanowires was also confirmed by EDX spectra. The optical properties of as grown Cu-doped SnO{sub 2} nanowires were studied by using UV-vis spectra which concludes the band gap of about 3.7 eV. As synthesized single Cu-doped SnO{sub 2} nanowire based gas sensor exhibit relatively good performance to ethanol gas. This sensing behaviour offers a suitable application of the Cu-doped SnO{sub 2} nanowire sensor for detection of ethanol gas.

  8. Layered CU-based electrode for high-dielectric constant oxide...

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

    candidate to replace Pt due to its low-cost, high conductivity and easier reactive etching properties. However, the successful substitution of Cu into thin-film devices...

  9. Controlling superconductivity in La2-xSrxCuO4+δ by ozone and...

    Office of Scientific and Technical Information (OSTI)

    Journal Article: Controlling superconductivity in La2-xSrxCuO4+ by ozone and vacuum annealing Citation Details In-Document Search Title: Controlling superconductivity in ...

  10. Microstructure and Corrosion Behavior of the Cu-Pd-X Ternary...

    Office of Scientific and Technical Information (OSTI)

    Microstructure and Corrosion Behavior of the Cu-Pd-X Ternary Alloys for Hydrogen Separation Membranes Citation Details In-Document Search Title: Microstructure and Corrosion...

  11. In-situ surface composition measurements of CuGaSe{sub 2} thin films

    SciTech Connect (OSTI)

    Fons, P.; Yamada, A.; Niki, S.; Oyanagi, H.

    1998-12-31

    Two CuGaSe{sub 2} films were grown by molecular beam epitaxy onto GaAs (001) substrates with varying Cu/Ga flux ratios under Se overpressure conditions. Growth was interrupted at predetermined times and the surface composition was measured using Auger electron spectroscopy after which growth was continued. After growth, the film composition was analyzed using voltage dependent electron microprobe spectroscopy. Film structure and morphology were also analyzed using x-ray diffraction and atomic force microscopy. The film with a Cu/Ga ratio larger than unity showed evidence of surface segregation of a second Cu-rich phase with a Cu/Se composition ratio slightly greater than unity. A second CuGaSe{sub 2} film with a Cu/Ga ratio of less than unity showed no change in surface composition with time and was also consistent with bulk composition measurements. Diffraction measurements indicated a high concentration of twins as well as the presence of domains with mixed c and a axes in the Ga-rich film. The Cu-rich films by contrast were single domain and had a narrower mosaics. High sensitivity scans along the [001] reciprocal axis did not exhibit any new peaks not attributable to either the substrate or the CuGaSe{sub 2} thin film.

  12. Recrystallization method to selenization of thin-film Cu(In,Ga)Se.sub.2 for semiconductor device applications

    DOE Patents [OSTI]

    Albin, David S.; Carapella, Jeffrey J.; Tuttle, John R.; Contreras, Miguel A.; Gabor, Andrew M.; Noufi, Rommel; Tennant, Andrew L.

    1995-07-25

    A process for fabricating slightly Cu-poor thin-films of Cu(In,Ga)Se.sub.2 on a substrate for semiconductor device applications includes the steps of forming initially a slightly Cu-rich, phase separated, mixture of Cu(In,Ga)Se.sub.2 :Cu.sub.x Se on the substrate in solid form followed by exposure of the Cu(In,Ga)Se.sub.2 :Cu.sub.x Se solid mixture to an overpressure of Se vapor and (In,Ga) vapor for deposition on the Cu(In,Ga)Se.sub.2 :Cu.sub.x Se solid mixture while simultaneously increasing the temperature of the solid mixture toward a recrystallization temperature (about 550.degree. C.) at which Cu(In,Ga)Se.sub.2 is solid and Cu.sub.x Se is liquid. The (In,Ga) flux is terminated while the Se overpressure flux and the recrystallization temperature are maintained to recrystallize the Cu.sub.x Se with the (In, Ga) that was deposited during the temperature transition and with the Se vapor to form the thin-film of slightly Cu-poor Cu.sub.x (In,Ga).sub.y Se.sub.z. The initial Cu-rich, phase separated large grain mixture of Cu(In,Ga)Se.sub.2 :Cu.sub.x Se can be made by sequentially depositing or co-depositing the metal precursors, Cu and (In, Ga), on the substrate at room temperature, ramping up the thin-film temperature in the presence of Se overpressure to a moderate anneal temperature (about 450.degree. C.) and holding that temperature and the Se overpressure for an annealing period. A nonselenizing, low temperature anneal at about 100.degree. C. can also be used to homogenize the precursors on the substrates before the selenizing, moderate temperature anneal.

  13. Low thermal budget photonic processing of highly conductive Cu interconnects based on CuO nanoinks. Potential for flexible printed electronics

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Rager, Matthew S.; Aytug, Tolga; Veith, Gabriel M.; Joshi, Pooran C.

    2015-12-31

    The developing field of printed electronics nanoparticle based inks such as CuO show great promise as a low-cost alternative to other metal-based counterparts (e.g., silver). In particular, CuO inks significantly eliminate the issue of particle oxidation, before and during the sintering process, that is prevalent in Cu-based formulations. We report here the scalable and low-thermal budget photonic fabrication of Cu interconnects employing a roll-to-roll compatible pulse-thermal-processing (PTP) technique that enables phase reduction and subsequent sintering of inkjet-printed CuO patterns onto flexible polymer templates. Detailed investigations of curing and sintering conditions were performed to understand the impact of PTP system conditionsmore » on the electrical performance of the Cu patterns. Specifically, the impact of energy and power of photonic pulses on print conductivity was systematically studied by varying the following key processing parameters: pulse intensity, duration and sequence. Through optimization of such parameters, highly conductive prints in < 1 s with resistivity values as low as 100 n m has been achieved. We also observed that the introduction of an initial ink-drying step in ambient atmosphere, after the printing and before sintering, leads to significant improvements in mechanical integrity and electrical performance of the printed Cu patterns. Moreover, the viability of CuO reactive inks, coupled with the PTP technology and pre ink-drying protocols, has also been demonstrated for the additive integration of a low-cost Cu temperature sensor onto a flexible polymer substrate.« less

  14. Low thermal budget photonic processing of highly conductive Cu interconnects based on CuO nanoinks. Potential for flexible printed electronics

    SciTech Connect (OSTI)

    Rager, Matthew S.; Aytug, Tolga; Veith, Gabriel M.; Joshi, Pooran C.

    2015-12-31

    The developing field of printed electronics nanoparticle based inks such as CuO show great promise as a low-cost alternative to other metal-based counterparts (e.g., silver). In particular, CuO inks significantly eliminate the issue of particle oxidation, before and during the sintering process, that is prevalent in Cu-based formulations. We report here the scalable and low-thermal budget photonic fabrication of Cu interconnects employing a roll-to-roll compatible pulse-thermal-processing (PTP) technique that enables phase reduction and subsequent sintering of inkjet-printed CuO patterns onto flexible polymer templates. Detailed investigations of curing and sintering conditions were performed to understand the impact of PTP system conditions on the electrical performance of the Cu patterns. Specifically, the impact of energy and power of photonic pulses on print conductivity was systematically studied by varying the following key processing parameters: pulse intensity, duration and sequence. Through optimization of such parameters, highly conductive prints in < 1 s with resistivity values as low as 100 n m has been achieved. We also observed that the introduction of an initial ink-drying step in ambient atmosphere, after the printing and before sintering, leads to significant improvements in mechanical integrity and electrical performance of the printed Cu patterns. Moreover, the viability of CuO reactive inks, coupled with the PTP technology and pre ink-drying protocols, has also been demonstrated for the additive integration of a low-cost Cu temperature sensor onto a flexible polymer substrate.

  15. La??xSrxCuO? superconductor nanowire devices

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Litombe, N. E.; Bollinger, A. T.; Hoffman, J. E.; Bozovic, I.

    2014-07-02

    La??xSrxCuO? nanowire devices have been fabricated and characterized using electrical transport measurements. Nanowires with widths down to 80 nm are patterned using high-resolution electron beam lithography. However, the narrowest nanowires show incomplete superconducting transitions with some residual resistance at T = 4 K. Here, we report on refinement of the fabrication process to achieve narrower nanowire devices with complete superconducting transitions, opening the path to the study of novel physics arising from dimension-limited superconductivity on the nanoscale.

  16. Effect of gamma irradiation on electrical properties of Cu nanowires

    SciTech Connect (OSTI)

    Rana, Pallavi Gehlawat, Devender Chauhan, R. P.

    2014-04-24

    Metallic nanowires are of great interest due to their unique electrical, optical, chemical and magnetic properties. Characterization and explanations of electronic properties of nanowires are extremely important due to their potential applications in the field of nanoelectronics and optoelectronics. In the present study, we synthesized the copper nanowires of different diameters (80nm, 100nm and 200nm) and exposed them with gamma rays of 100 KGy and 150 KGy doses. The I-V characteristics of different diameter of Cu nanowires before and after the irradiation were recorded.

  17. Cu-Ni-Fe anodes having improved microstructure

    DOE Patents [OSTI]

    Bergsma, S. Craig; Brown, Craig W.

    2004-04-20

    A method of producing aluminum in a low temperature electrolytic cell containing alumina dissolved in an electrolyte. The method comprises the steps of providing a molten electrolyte having alumina dissolved therein in an electrolytic cell containing the electrolyte. A non-consumable anode and cathode is disposed in the electrolyte, the anode comprised of Cu--Ni--Fe alloys having single metallurgical phase. Electric current is passed from the anode, through the electrolyte to the cathode thereby depositing aluminum on the cathode, and molten aluminum is collected from the cathode.

  18. Fermi surface measurements in YBa sub 2 Cu sub 3 O sub 7-x and La sub 1. 874 Sr sub. 126 CuO sub 4

    SciTech Connect (OSTI)

    Howell, R.H.; Sterne, P.A.; Solal, F.; Fluss, M.J. ); Haghighi, H.; Kaiser, J.H.; Rayner, S.L.; West, R.N. ); Liu, J.Z; Shelton, R. ); Kojima, H. ); Kitazawa, K. )

    1991-06-25

    We report new, ultra high precision measurements of the electron-positron momentum spectra of YBa{sub 2}Cu{sub 3}O{sub 7-x} and La{sub 1.874}Sr{sub 126}CuO{sub 4}. The YBCO experiments were performed on twin free, single crystals and show discontinuities with the symmetry of the Fermi surface of the CuO chain bands. Conduction band and underlying features in LSCO share the same symmetry and can only be separated with the aid of LDA calculations. 5 refs., 3 figs.

  19. Controlled preparation of Ag–Cu{sub 2}O nanocorncobs and their enhanced photocatalytic activity under visible light

    SciTech Connect (OSTI)

    Yang, Siyuan; Zhang, Shengsen; Wang, Hongjuan; Yu, Hao; Fang, Yueping; Peng, Feng

    2015-10-15

    Graphical abstract: The corncob-like Ag–Cu{sub 2}O nanostructure with suitably exposed Ag surface exhibited much higher photocatalytic activity than Ag@Cu{sub 2}O nanocables and Cu{sub 2}O nanowires. - Highlights: • Ag–Cu{sub 2}O nanocorncobs have been controllably prepared by a simple synthesis. • The possible formation mechanism of Ag–Cu{sub 2}O has been studied. • Ag–Cu{sub 2}O exhibits noticeable improved photocurrent compared with the pure Cu{sub 2}O NWs. • Ag–Cu{sub 2}O with suitably exposed Ag surface shows much higher photocatalytic activity. - Abstract: Novel corncob-like nano-heterostructured Ag–Cu{sub 2}O photocatalyst has been controllably prepared by adjusting the synthetic parameters, and the possible formation mechanism has been also studied. The photoelectrochemical and photocatalytic performances demonstrated that the as-prepared Ag–Cu{sub 2}O nanocorncobs exhibited higher photocatalytic activity than both pure Cu{sub 2}O nanowires and cable-like Ag@Cu{sub 2}O nano-composites. It was concluded that Ag–Cu{sub 2}O nanocorncobs with suitably exposed Ag surface not only effectively inhibit the recombination of electron–hole pairs but also suitably increase the active sites of electronic conduction, and thus increasing the photocatalytic activity under visible light irradiation.

  20. Shock-induced consolidation and spallation of Cu nanopowders

    SciTech Connect (OSTI)

    Huang, L.; Han, W. Z.; Luo, S. N.; An, Q.; Goddard, W. A. III

    2012-01-01

    A useful synthesis technique, shock synthesis of bulk nanomaterials from nanopowders, is explored here with molecular dynamics simulations. We choose nanoporous Cu ({approx}11 nm in grain size and 6% porosity) as a representative system, and perform consolidation and spallation simulations. The spallation simulations characterize the consolidated nanopowders in terms of spall strength and damage mechanisms. The impactor is full density Cu, and the impact velocity (u{sub i}) ranges from 0.2 to 2 km s{sup -1}. We present detailed analysis of consolidation and spallation processes, including atomic-level structure and wave propagation features. The critical values of u{sub i} are identified for the onset plasticity at the contact points (0.2 km s{sup -1}) and complete void collapse (0.5 km s{sup -1}). Void collapse involves dislocations, lattice rotation, shearing/friction, heating, and microkinetic energy. Plasticity initiated at the contact points and its propagation play a key role in void collapse at low u{sub i}, while the pronounced, grain-wise deformation may contribute as well at high u{sub i}. The grain structure gives rise to nonplanar shock response at nanometer scales. Bulk nanomaterials from ultrafine nanopowders ({approx}10 nm) can be synthesized with shock waves. For spallation, grain boundary (GB) or GB triple junction damage prevails, while we also observe intragranular voids as a result of GB plasticity.

  1. J/psi production at high transverse momenta in p+p and Cu+Cu collisions at sqrt sNN = 200 GeV

    SciTech Connect (OSTI)

    STAR Collaboration; Abelev, B. I.

    2009-10-27

    The STAR collaboration at RHIC presents measurements of J/{psi} {yields} e{sup +}e{sup -} at mid-rapidity and high transverse momentum (p{sub T} > 5 GeV/c) in p+p and central Cu+Cu collisions at {radical}sNN = 200 GeV. The inclusive J/{psi} production cross section for Cu+Cu collisions is found to be consistent at high p{sub T} with the binary collision-scaled cross section for p+p collisions, in contrast to previous measurements at lower p{sub T}, where a suppression of J/{psi} production is observed relative to the expectation from binary scaling. Azimuthal correlations of J/{psi} with charged hadrons in p+p collisions provide an estimate of the contribution of B-meson decays to J/{psi} production of 13% {+-} 5%.

  2. Measurement of K0S and K*0 in p+p, d+Au, and Cu+Cu collisions at sqrt SNN = 200 GeV

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Adare, A.; Aidala, C.

    2014-11-01

    The PHENIX experiment at the Relativistic Heavy Ion Collider has performed a systematic study of K0S and K*0 meson production at midrapidity in p+p, d+Au, and Cu+Cu collisions at sqrt SNN = 200 GeV. The K0S and K*0 mesons are reconstructed via their K0S and π0(→γγ)π0 (→γγ) and K*0 → K ±#25;π± decay modes, respectively. The measured transverse-momentum spectra are used to determine the nuclear modification factor of K0S and K*0 mesons in d+Au and Cu+Cu collisions at different centralities. In the d+Au collisions, the nuclear modification factor of K0S and K*0 mesons is almost constant as a function ofmore »transverse momentum and is consistent with unity showing that cold-nuclear-matter effects do not play a significant role in the measured kinematic range. In Cu+Cu collisions, within the uncertainties no nuclear modification is registered in peripheral collisions. In central collisions, both mesons show suppression relative to the expectations from the p+p yield scaled by the number of binary nucleon-nucleon collisions in the Cu+Cu system. In the pT range 2–5 GeV/c, the strange mesons ( K0S, K*0) similarly to the #30;Φ meson with hidden strangeness, show an intermediate suppression between the more suppressed light quark mesons (π0) and the nonsuppressed baryons (p, p-bar). At higher transverse momentum, pT > 5 GeV/c, production of all particles is similarly suppressed by a factor of ≈2. (auth)« less

  3. Measurement of K0S and K*0 in p+p, d+Au, and Cu+Cu collisions at sqrt SNN = 200 GeV

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Adare, A.; Aidala, C.

    2014-11-01

    The PHENIX experiment at the Relativistic Heavy Ion Collider has performed a systematic study of K0S and K*0 meson production at midrapidity in p+p, d+Au, and Cu+Cu collisions at sqrt SNN = 200 GeV. The K0S and K*0 mesons are reconstructed via their K0S and π0(→γγ)π0 (→γγ) and K*0 → K ±#25;π± decay modes, respectively. The measured transverse-momentum spectra are used to determine the nuclear modification factor of K0S and K*0 mesons in d+Au and Cu+Cu collisions at different centralities. In the d+Au collisions, the nuclear modification factor of K0S and K*0 mesons is almost constant as a function ofmore » transverse momentum and is consistent with unity showing that cold-nuclear-matter effects do not play a significant role in the measured kinematic range. In Cu+Cu collisions, within the uncertainties no nuclear modification is registered in peripheral collisions. In central collisions, both mesons show suppression relative to the expectations from the p+p yield scaled by the number of binary nucleon-nucleon collisions in the Cu+Cu system. In the pT range 2–5 GeV/c, the strange mesons ( K0S, K*0) similarly to the #30;Φ meson with hidden strangeness, show an intermediate suppression between the more suppressed light quark mesons (π0) and the nonsuppressed baryons (p, p-bar). At higher transverse momentum, pT > 5 GeV/c, production of all particles is similarly suppressed by a factor of ≈2. (auth)« less

  4. Preferential Cu precipitation at extended defects in bcc Fe: An atomistic study

    SciTech Connect (OSTI)

    Zhang, Yongfeng; Millett, Paul C.; Tonks, Michael R.; Bai, Xian-Ming; Biner, S. Bulent

    2015-04-01

    As a starting point to understand Cu precipitation in RPV alloys, molecular dynamics and Metropolis Monte-Carlo simulations are carried out to study the effect of lattice defects on Cu precipitation by taking Fe-Cu system as a model alloy. Molecular dynamics simulations show that owing to the high heat of mixing and positive size mismatch, Cu is attracted by vacancy type defects such as vacancies and voids, and tensile stress fields. In accordance, preferential precipitation of Cu is observed in Metropolis Monte-Carlo simulations at dislocations, prismatic loops and voids. The interaction of Cu with a stress field, e.g., that associated with a dislocation or a prismatic loop, is dominated by elastic effect and can be well described by the linear-elasticity theory. For prismatic loops, the attraction to Cu is found to be size-dependent with opposite trends displayed by vacancy and interstitial loops. The size-dependences can be explained by considering the stress fields produced by these loops. The current results will be useful for understanding the effect of neutron irradiation on Cu precipitation in reactor-pressure-vessel steels.

  5. Compositionally graded SiCu thin film anode by magnetron sputtering for lithium ion battery

    SciTech Connect (OSTI)

    Polat, B. D.; Eryilmaz, O. L.; Keles, O; Erdemir, A; Amine, Khalil

    2015-10-22

    Compositionally graded and non-graded composite SiCu thin films were deposited by magnetron sputtering technique on Cu disks for investigation of their potentials in lithium ion battery applications. The compositionally graded thin film electrodes with 30 at.% Cu delivered a 1400 mAh g-1 capacity with 80% Coulombic efficiency in the first cycle and still retained its capacity at around 600 mAh g-1 (with 99.9% Coulombic efficiency) even after 100 cycles. On the other hand, the non-graded thin film electrodes with 30 at.% Cu exhibited 1100 mAh g-1 as the first discharge capacity with 78% Coulombic efficiency but the cycle life of this film degraded very quickly, delivering only 250 mAh g-1 capacity after 100th cycles. Not only the Cu content but also the graded film thickness were believed to be the main contributors to the much superior performance of the compositionally graded SiCu films. We also believe that the Cu-rich region of the graded film helped reduce internal stress build-up and thus prevented film delamination during cycling. In particular, the decrease of Cu content from interface region to the top of the coating reduced the possibility of stress build-up across the film during cycling, thus leading to a high electrochemical performance.

  6. Interaction of CuS and sulfur in Li-S battery system

    SciTech Connect (OSTI)

    Sun, Ke; Su, Dong; Zhang, Qing; Bock, David C.; Marschilok, Amy C.; Takeuchi, Kenneth J.; Takeuchi, Esther S.; Gan, Hong

    2015-10-27

    Lithium-Sulfur (Li-S) battery has been a subject of intensive research in recent years due to its potential to provide much higher energy density and lower cost than the current state of the art lithiumion battery technology. In this work, we have investigated Cupric Sulfide (CuS) as a capacitycontributing conductive additive to the sulfur electrode in a Li-S battery. Galvanostatic charge/discharge cycling has been used to compare the performance of both sulfur electrodes and S:CuS hybrid electrodes with various ratios. We found that the conductive CuS additive enhanced the utilization of the sulfur cathode under a 1C rate discharge. However, under a C/10 discharge rate, S:CuS hybrid electrodes exhibited lower sulfur utilization in the first discharge and faster capacity decay in later cycles than a pure sulfur electrode due to the dissolution of CuS. The CuS dissolution is found to be the result of strong interaction between the soluble low order polysulfide Li2S3 and CuS. As a result, we identified the presence of conductive copper-containing sulfides at the cycled lithium anode surface, which may degrade the effectiveness of the passivation function of the solid-electrolyte-interphase (SEI) layer, accounting for the poor cycling performance of the S:CuS hybrid cells at low rate.

  7. Ultrasound-assisted synthesis of CuO nanostructures templated by cotton fibers

    SciTech Connect (OSTI)

    Zou, Yunling; Li, Yan; Guo, Ying; Zhou, Qingjun; An, Dongmin

    2012-11-15

    Highlights: ? Flower-like and corn-like CuO nanostructures were synthesized by a simple method. ? Cotton fibers purchased from commercially are used as template. ? The concentration of Cu(NO{sub 3}){sub 2} solution is an important parameter. -- Abstract: Flower-like and corn-like CuO nanostructures composed of CuO nanoparticles were successfully synthesized via ultrasound-assisted template method, respectively, by controlling the initial concentration of Cu(NO{sub 3}){sub 2} solution. Here, cotton fibers were used as template agent. The products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), field-emission scanning electron microscopy (FE-SEM) and energy-dispersive spectroscopy (EDS), respectively. The results demonstrated that the initial concentration of Cu(NO{sub 3}){sub 2} solution was an important parameter for determining whether CuO nanoparticles assembled into flower-like structures or corn-like structures. The mechanism of forming different nanostructures of CuO was discussed.

  8. Fundamental studies of high-temperature corrosion reactions. Sixth annual progress report. [Cu-6% Ni

    SciTech Connect (OSTI)

    Rapp, R.A.

    1981-02-01

    Research was conducted on the sulfidation of pure Mo by sulfur gases at 700 to 950/sup 0/C and on the in-situ oxidation of metals and alloys in the hot-stage SEM. Results on the in-situ oxidation of Cu, Ni, Fe, and Cu-6% Ni up to 930/sup 0/C are reported in detail. 21 figures.

  9. Electronic and structural properties at the interface between CuPc and graphene

    SciTech Connect (OSTI)

    Tao, Yongsheng; Mao, Hongying; He, Pimo

    2015-01-07

    The electronic and structural properties at Copper phthalocyanine (CuPc)/graphene have been studied using ultraviolet photoemission spectroscopy and first-principles density function theory calculation. The five emission features ?, ?, ?, ?, and ? originating from the CuPc molecules locate at 1.48, 3.66, 4.98, 6.90, and 9.04?eV, respectively. These features shift in binding energy with the increasing CuPc coverage. The feature ? is mostly deriving from Cu 3d orbital with some contributions from C 2p orbital. Further theoretical calculation indicates that the adsorption of CuPc on a top site is the most favorable configuration, and the separation between the adsorbate and graphene is about 3.47?. According to the density of states before and after CuPc adsorption, the LUMO of CuPc is slightly occupied, while the Dirac point of graphene slightly shift towards higher energy, suggesting that a small amount of electron transfer from graphene to CuPc upon contact.

  10. Interaction of CuS and sulfur in Li-S battery system

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Sun, Ke; Su, Dong; Zhang, Qing; Bock, David C.; Marschilok, Amy C.; Takeuchi, Kenneth J.; Takeuchi, Esther S.; Gan, Hong

    2015-10-27

    Lithium-Sulfur (Li-S) battery has been a subject of intensive research in recent years due to its potential to provide much higher energy density and lower cost than the current state of the art lithiumion battery technology. In this work, we have investigated Cupric Sulfide (CuS) as a capacitycontributing conductive additive to the sulfur electrode in a Li-S battery. Galvanostatic charge/discharge cycling has been used to compare the performance of both sulfur electrodes and S:CuS hybrid electrodes with various ratios. We found that the conductive CuS additive enhanced the utilization of the sulfur cathode under a 1C rate discharge. However, undermore » a C/10 discharge rate, S:CuS hybrid electrodes exhibited lower sulfur utilization in the first discharge and faster capacity decay in later cycles than a pure sulfur electrode due to the dissolution of CuS. The CuS dissolution is found to be the result of strong interaction between the soluble low order polysulfide Li2S3 and CuS. As a result, we identified the presence of conductive copper-containing sulfides at the cycled lithium anode surface, which may degrade the effectiveness of the passivation function of the solid-electrolyte-interphase (SEI) layer, accounting for the poor cycling performance of the S:CuS hybrid cells at low rate.« less

  11. Growth and magnetic property of antiperovskite manganese nitride films doped with Cu by molecular beam epitaxy

    SciTech Connect (OSTI)

    Yu, Fengmei; Ren, Lizhu; Meng, Meng; Wang, Yunjia; Yang, Mei; Wu, Shuxiang; Li, Shuwei

    2014-04-07

    Manganese nitrides thin films on MgO (100) substrates with and without Cu-doping have been fabricated by plasma assisted molecular beam epitaxy. Antiperovskite compounds Mn{sub 3.6}Cu{sub 0.4}N have been grown in the case of Cu-doping, and the pure Mn{sub 3}N{sub 2} single crystal has been obtained without Cu-doping. The Mn{sub 3.6}Cu{sub 0.4}N exhibits ferrimagnetism, and the magnetization of Mn{sub 3.6}Cu{sub 0.4}N increases upon the temperature decreasing from 300 K to 5 K, similar to Mn{sub 4}N. The exchange bias (EB) effects emerge in the Mn{sub 3.6}Cu{sub 0.4}N films. The EB behavior is originated from the interfaces between ferrimagnetic Mn{sub 3.6}Cu{sub 0.4}N and antiferromagnetic metal Mn, which is verified to be formed by the data of x-ray photoelectron spectroscopy. The present results not only provide a strategy for producing functional antiperovskite manganese nitrides, but also shed promising light on fabricating the exchange bias part of spintronic devices.

  12. Development of a Low Cost Insulated Foil Substrate for Cu(InGaSe)2 Photovoltaics

    SciTech Connect (OSTI)

    ERTEN ESER

    2012-01-22

    The project validated the use of stainless steel flexible substrate coated with silicone-based resin dielectric, developed by Dow Corning Corporation, for Cu(InGa)Se2 based photovoltaics. The projects driving force was the high performance of Cu(InGa)Se2 based photovoltaics coupled with potential cost reduction that could be achieved with dielectric coated SS web substrate.

  13. Ab-initio study of donor-acceptor codoping for n-type CuO

    SciTech Connect (OSTI)

    Peng, Yuan; Wang, Junling, E-mail: jlwang@ntu.edu.sg [School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore); Zheng, Jianwei [Institute of High Performance Computing, 1 Fusionopolis Way, #16-16 Connexis, Singapore 138632 (Singapore); Wu, Ping [Engineering Product Development, Singapore University of Technology and Design, 20 Dover Drive, Singapore 138682 (Singapore)

    2014-10-28

    Single n-type dopant in CuO has either a deep donor level or limited solubility, inefficient in generating free electrons. We have performed ab-initio study of the donor-acceptor codoping to obtain n-type CuO. Our results show that N codoping can slightly improve the donor level of Zr and In by forming shallower n-type complexes (Zr{sub Cu}-N{sub O} and 2In{sub Cu}-N{sub O}), but their formation energies are too high to be realized in experiments. However, Li codoping with Al and Ga is found to be relatively easy to achieve. 2Al{sub Cu}-Li{sub Cu} and 2Ga{sub Cu}-Li{sub Cu} have shallower donor levels than single Al and Ga by 0.14?eV and 0.08?eV, respectively, and their formation energies are reasonably low to act as efficient codopants. Moreover, Li codoping with both Al and Ga produce an empty impurity band just below the host conduction band minimum, which may reduce the donor ionization energy at high codoping concentrations.

  14. Metallicity of Ca2Cu6P5 with single and double copper-pnictide layers

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Li, Li; Parker, David; Chi, Miaofang; Tsoi, Georgiy M.; Vohra, Yogesh K.; Sefat, Athena S.

    2016-02-16

    Here, we report thermodynamic and transport properties, and also theoretical calculations, for Cu-based compound Ca2Cu6P5 and compare with CaCu2-dP2. Both materials have layers of edge-sharing copper pnictide tetrahedral CuP4, similar to Fe–As and Fe–Se layers (with FeAs4, FeSe4) in the iron-based superconductors. Despite the presence of this similar transition-metal pnictide layer, we find that both Ca2Cu6P5 and CaCu2-δP2 have temperature-independent magnetic susceptibility and show metallic behavior with no evidence of either magnetic ordering or superconductivity down to 1.8 K CaCu2-δP2 is slightly off-stoichiometric, with δ = 0.14. Theoretical calculations suggest that unlike Fe 3d-based magnetic materials with a large densitymore » of states (DOS) at the Fermi surface, Cu have comparatively low DOS, with the majority of the 3d spectral weight located well below Fermi level. The room-temperature resistivity value of Ca2Cu6P5 is only 9 μΩ-cm, due to a substantial plasma frequency and an inferred electron-phonon coupling λ of 0.073 (significantly smaller than that of metallic Cu). Also, microscopy result shows that Cu–Cu distance along the c-axis within the double layers can be very short (2.5 Å), even shorter than metallic elemental copper bond (2.56 Å). The value of dρ/dT for CaCu2-δP2 at 300 K is approximately three times larger than in Ca2Cu6P5, which suggests the likelihood of stronger electron-phonon coupling. This study shows that the details of Cu-P layers and bonding are important for their transport characteristics. In addition, it emphasizes the remarkable character of the DOS of ‘122’ iron-based materials, despite much structural similarities.« less

  15. CuInSe/sub 2/-based photoelectrochemical cells: their use in characterization of thin CuInSe/sub 2/ films, and as photovoltaic cells per se

    SciTech Connect (OSTI)

    Cahen, D.; Chen, Y.W.; Ireland, P.J.; Noufi, R.; Turner, J.A.; Rincon, C.; Bachmann, K.J.

    1984-05-01

    Photoelectrochemistry has been employed to characterize the p-CuInSe/sub 2/ component of the CdS/CuInSe/sub 2/ on-metal and a nonaqueous electrolyte containing a redox couple not specifically adsorbed onto the semiconductor, we can test the films for photovoltaic activity and obtain effective electronic properties of them, before CdS deposition, in a nondestructive manner. Electrochemical decomposition of CuInSe/sub 2/ was investigated in acetonitrile solutions to determine the mechanism of decomposition (n and p) in the dark and under illumination. Electrochemical, solution chemical and surface analyses confirmed at the light-assisted decomposition of CuInSe/sub 2/ resulted in metal ions and elemental chalcogen. On the basis of the results from the electrochemical decomposition, and studies on the solid state chemistry of the (Cu/sub 2/Se)/sub x/(In/sub 2/Se/sub 3/)/sub 1-x/ system and surface analyses, the CuInSe/sub 2//polyiodide interface was stabilized and up to 11.7% conversion efficiencies were obtained.

  16. Magnetic order tuned by Cu substitution in Fe1.1–zCuzTe

    SciTech Connect (OSTI)

    Wen, Jinsheng; Xu, Zhijun; Xu, Guangyong; Lumsden, M. D.; Valdivia, P. N.; Bourret-Courchesne, E.; Gu, Genda; Lee, Dung-Hai; Tranquada, J. M.; Birgeneau, R. J.

    2012-07-02

    We study the effects of Cu substitution in Fe₁.₁Te, the nonsuperconducting parent compound of the iron-based superconductor, Fe₁₊yTe₁₋xSex, utilizing neutron scattering techniques. It is found that the structural and magnetic transitions, which occur at ~60 K without Cu, are monotonically depressed with increasing Cu content. By 10% Cu for Fe, the structural transition is hardly detectable, and the system becomes a spin glass below 22 K, with a slightly incommensurate ordering wave vector of (0.5–δ, 0, 0.5) with δ being the incommensurability of 0.02, and correlation length of 12 Å along the a axis and 9 Å along the c axis. With 4% Cu, both transition temperatures are at 41 K, though short-range incommensurate order at (0.42, 0, 0.5) is present at 60 K. With further cooling, the incommensurability decreases linearly with temperature down to 37 K, below which there is a first-order transition to a long-range almost-commensurate antiferromagnetic structure. A spin anisotropy gap of 4.5 meV is also observed in this compound. Our results show that the weakly magnetic Cu has a large effect on the magnetic correlations; it is suggested that this is caused by the frustration of the exchange interactions between the coupled Fe spins.

  17. Identified high-pT spectra in Cu+Cu collisions at sqrt sNN=200 GeV

    SciTech Connect (OSTI)

    STAR Collaboration; Abelev, Betty

    2010-07-05

    We report new results on identified (anti)proton and charged pion spectra at large transverse momenta (3 < p{sub T} < 10 GeV/c) from Cu+Cu collisions at {radical}s{sub NN} = 200 GeV using the STAR detector at the Relativistic Heavy Ion Collider (RHIC). This study explores the system size dependence of two novel features observed at RHIC with heavy ions: the hadron suppression at high-p{sub T} and the anomalous baryon to meson enhancement at intermediate transverse momenta. Both phenomena could be attributed to the creation of a new form of QCD matter. The results presented here bridge the system size gap between the available pp and Au+Au data, and allow the detailed exploration for the on-set of the novel features. Comparative analysis of all available 200 GeV data indicates that the system size is a major factor determining both the magnitude of the hadron spectra suppression at large transverse momenta and the relative baryon to meson enhancement.

  18. Mechanical properties of Al-Cu alloy-SiC composites

    SciTech Connect (OSTI)

    Anggara, B. S.; Handoko, E.; Soegijono, B.

    2014-09-25

    The synthesis of aluminum (Al) alloys, Al-Cu, from mixture 96.2 % Al and 3.8 % Cu has been prepared by melting process at a temperature of 1200°C. The adding 12.5 wt% up to 20 wt% of SiC on Al-Cu alloys samples has been investigated. The structure analyses were examined by X-Ray Diffractometer (XRD) and scanning electron microscope (SEM). Moreover, the morphology of Al-Cu alloys has been seen as structure in micrometer range. The hardness was measured by hardness Vickers method. According to the results, it can be assumed that the 15 wt% of SiC content is prefer content to get better quality of back to back hardness Vickers of Al-Cu alloys.

  19. Facile synthesis of Ag–Cu{sub 2}O composites with enhanced photocatalytic activity

    SciTech Connect (OSTI)

    Yang, Jianbo; Li, Zhen; Zhao, Caixin; Wang, Yang; Liu, Xueqin

    2014-12-15

    Highlights: • Ag–Cu{sub 2}O nanocomposites were synthesized via awet-chemical precipitation route. • The growth temperature does not exceed 50 °C in any step of the synthesis. • Enhanced photocurrent of Ag–Cu{sub 2}O composites, compared to pure Cu{sub 2}O particles. • The photocatalytic property was studied upon simulated sunlight. • Enhanced photocatalytic property of Ag–Cu{sub 2}O composites, compared to pure Cu{sub 2}O particles. - Abstract: Silver–cuprous oxide (Ag–Cu{sub 2}O) microcomposites are successfully prepared by a facile low-cost solution method. The obtained materials were characterized by X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), field emission scanning electron microscopy (FESEM), ultraviolet–visible (UV–vis) spectroscopy, X-ray photoelectron spectroscopy (XPS). Experiments demonstrated that the formation of Ag–Cu{sub 2}O microcomposites was significantly influenced by the concentration of AgNO{sub 3}, and with increasing the concentration of AgNO{sub 3}, the optical absorption of the composites becomes strong. The photocatalytic activity of the prepared Ag–Cu{sub 2}O composites was determined by measuring the degradation of methyl orange solution under visible light, to find out its potential application in waste water treatment. The results reveal that the photocurrent of the composite is about 4 times higher than that of pure Cu{sub 2}O and the visible light photocatalytic activity of the composite is enhanced greatly on degradation of methyl orange. The reason for improvement in photocatalytic activity of the Ag–Cu{sub 2}O composites was also discussed.

  20. Enhanced quality thin film Cu(In,Ga)Se[sub 2] for semiconductor device applications by vapor-phase recrystallization

    DOE Patents [OSTI]

    Tuttle, J.R.; Contreras, M.A.; Noufi, R.; Albin, D.S.

    1994-10-18

    Enhanced quality thin films of Cu[sub w](In,Ga[sub y])Se[sub z] for semiconductor device applications are fabricated by initially forming a Cu-rich, phase-separated compound mixture comprising Cu(In,Ga):Cu[sub x]Se on a substrate to form a large-grain precursor and then converting the excess Cu[sub x]Se to Cu(In,Ga)Se[sub 2] by exposing it to an activity of In and/or Ga, either in vapor In and/or Ga form or in solid (In,Ga)[sub y]Se[sub z]. Alternatively, the conversion can be made by sequential deposition of In and/or Ga and Se onto the phase-separated precursor. The conversion process is preferably performed in the temperature range of about 300--600 C, where the Cu(In,Ga)Se[sub 2] remains solid, while the excess Cu[sub x]Se is in a liquid flux. The characteristic of the resulting Cu[sub w](In,Ga)[sub y]Se[sub z] can be controlled by the temperature. Higher temperatures, such as 500--600 C, result in a nearly stoichiometric Cu(In,Ga)Se[sub 2], whereas lower temperatures, such as 300--400 C, result in a more Cu-poor compound, such as the Cu[sub z](In,Ga)[sub 4]Se[sub 7] phase. 7 figs.

  1. Enhanced quality thin film Cu(In,Ga)Se.sub.2 for semiconductor device applications by vapor-phase recrystallization

    DOE Patents [OSTI]

    Tuttle, John R.; Contreras, Miguel A.; Noufi, Rommel; Albin, David S.

    1994-01-01

    Enhanced quality thin films of Cu.sub.w (In,Ga.sub.y)Se.sub.z for semiconductor device applications are fabricated by initially forming a Cu-rich, phase-separated compound mixture comprising Cu(In,Ga):Cu.sub.x Se on a substrate to form a large-grain precursor and then converting the excess Cu.sub.x Se to Cu(In,Ga)Se.sub.2 by exposing it to an activity of In and/or Ga, either in vapor In and/or Ga form or in solid (In,Ga).sub.y Se.sub.z. Alternatively, the conversion can be made by sequential deposition of In and/or Ga and Se onto the phase-separated precursor. The conversion process is preferably performed in the temperature range of about 300.degree.-600.degree. C., where the Cu(In,Ga)Se.sub.2 remains solid, while the excess Cu.sub.x Se is in a liquid flux. The characteristic of the resulting Cu.sub.w (In,Ga).sub.y Se.sub.z can be controlled by the temperature. Higher temperatures, such as 500.degree.-600.degree. C., result in a nearly stoichiometric Cu(In,Ga)Se.sub.2, whereas lower temperatures, such as 300.degree.-400.degree. C., result in a more Cu-poor compound, such as the Cu.sub.z (In,Ga).sub.4 Se.sub.7 phase.

  2. Three 3D hybrid networks based on octamolybdates and different Cu{sup I}/Cu{sup II}-bis(triazole) motifs

    SciTech Connect (OSTI)

    Zhang, Chun-Jing; Pang, Hai-Jun; Tang, Qun; Wang, Hui-Yuan; Chen, Ya-Guang

    2010-12-15

    Three 3D compounds based on octamolybdate clusters and various Cu{sup I}/Cu{sup II}-bis(triazole) motifs, [Cu{sup I}{sub 2}btb][{beta}-Mo{sub 8}O{sub 26}]{sub 0.5} (1), [Cu{sup I}{sub 2}btpe][{beta}-Mo{sub 8}O{sub 26}]{sub 0.5} (2), and [Cu{sup II}(btpe){sub 2}][{beta}-Mo{sub 8}O{sub 26}]{sub 0.5} (3) [btb=1,4-bis(1,2,4-triazol-1-yl)butane, btpe=1,5-bis(1,2,4-triazol-1-yl)pentane], were isolated via tuning flexible ligand spacer length and metal coordination preferences. In 1, the copper(I)-btb motif is a one-dimensional (1D) chain which is further linked by hexadentate {beta}-[Mo{sub 8}O{sub 26}]{sup 4-} clusters via coordinating to Cu{sup I} cations giving a 3D structure. In 2, the copper(I)-btpe motif exhibits a 'stairs'-like [Cu{sup I}{sub 2}btpe]{sup 2+} sheet, and the tetradentate {beta}-[Mo{sub 8}O{sub 26}]{sup 4-} clusters interact with two neighboring [Cu{sup I}{sub 2}btpe]{sup 2+} sheets constructing a 3D framework. In 3, the copper(II)-btpe motif possesses a novel (2D{yields}3D) interdigitated structure, which is further connected by the tetradentate {beta}-[Mo{sub 8}O{sub 26}]{sup 4-} clusters forming a 3D framework. The thermal stability and luminescent properties of 1-3 are investigated in the solid state. -- Graphical abstract: Three 3D compounds based on {beta}-[Mo{sub 8}O{sub 26}]{sup 4-} clusters with different Cu{sup I}/Cu{sup II}-bis(triazole) motifs were synthesized by regularly tuning flexible ligand spacer length and metal coordination preferences. Display Omitted

  3. Kondo interactions from band reconstruction in YbInCu?

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Jarrige, I.; Kotani, A.; Yamaoka, H.; Tsujii, N.; Ishii, K.; Upton, M.; Casa, D.; Kim, J.; Gog, T.; Hancock, J. N.

    2015-03-27

    We combine resonant inelastic X-ray scattering (RIXS) and model calculations in the Kondo lattice compound YbInCu?, a system characterized by a dramatic increase in Kondo temperature and associated valence fluctuations below a first-order valence transition at T?42 K. The bulk-sensitive, element-specific, and valence-projected charge excitation spectra reveal an unusual quasi-gap in the Yb-derived state density which drives an instability of the electronic structure and renormalizes the low-energy effective Hamiltonian at the transition. Our results provide long-sought experimental evidence for a link between temperature-driven changes in the low-energy Kondo scale and the higher-energy electronic structure of this system.

  4. Crystallization in supercooled liquid Cu: Homogeneous nucleation and growth

    SciTech Connect (OSTI)

    E, J. C.; Wang, L.; Luo, S. N.; Cai, Y.; Wu, H. A.

    2015-02-14

    Homogeneous nucleation and growth during crystallization of supercooled liquid Cu are investigated with molecular dynamics simulations, and the microstructure is characterized with one- and two-dimensional x-ray diffraction. The resulting solids are single-crystal or nanocrystalline, containing various defects such as stacking faults, twins, fivefold twins, and grain boundaries; the microstructure is subject to thermal fluctuations and extent of supercooling. Fivefold twins form via sequential twinning from the solid-liquid interfaces. Critical nucleus size and nucleation rate at 31% supercooling are obtained from statistical runs with the mean first-passage time and survival probability methods, and are about 14 atoms and 10{sup 32} m{sup −3}s{sup −1}, respectively. The bulk growth dynamics are analyzed with the Johnson-Mehl-Avrami law and manifest three stages; the Avrami exponent varies in the range of 1–19, which also depends on thermal fluctuations and supercooling.

  5. Precipitates in a quasicrystal-strengthened Al–Mn–Be–Cu alloy

    SciTech Connect (OSTI)

    Zupanič, Franc; Wang, Di; Gspan, Cristian; Bončina, Tonica

    2015-08-15

    In this work, an Al–Mn–Be–Cu alloy was studied containing a primary and eutectic icosahedral quasicrystalline phase in the as-cast microstructure. Special attention was given to a transmission electron microscopy investigation of precipitates formed within the aluminium solid solution (Al{sub ss}) at different temperatures. At 200 °C, only binary Al–Cu precipitates (θ′) were formed. At 300 °C, icosahedral quasicrystalline (IQC) precipitates prevailed with a crystallographic orientation relationship with the Al{sub ss.} The rods of the T-phase (Al{sub 20}Mn{sub 3}Cu{sub 2}) which were precipitated above 400 °C, also had a specific orientation relationship with the Al{sub ss}. The primary and eutectic IQC microstructural constituent started to transform rapidly to the T-phase and Be{sub 4}Al(Mn,Cu) at 500 °C. - Highlights: • In a quasicrystal-strengthened Al-alloy several types of precipitates can form. • At 200 °C, only binary Al–Cu precipitates formed (Al{sub 2}Cu-θ′). • The icosahedral quasicrystalline (IQC) precipitates prevailed at 300 °C. • T-phase (Al{sub 20}Mn{sub 3}Cu{sub 2}) precipitated at temperatures above 400 °C. • The precipitation of different phases did not have a strong effect on hardness.

  6. Isothermal Solid-State Transformation Kinetics Applied to Pd/Cu Alloy Membrane Fabrication

    SciTech Connect (OSTI)

    Pomerantz, Natalie L; Payzant, E Andrew; Ma, Yi Hua

    2010-01-01

    In this work, time-resolved, in situ high-temperature X-ray diffraction (HT-XRD) was used to study the solid-state transformation kinetics of the formation of the fcc Pd/Cu alloy from Pd/Cu bi-layers for the purpose of fabricating sulfur tolerant Pd/Cu membranes for H2 separation. Thin layers of Pd and Cu (total ~15 wt% Cu) were deposited on porous stainless steel (PSS) with the electroless deposition method and annealed in H2 at 500, 550 and 600 C. The kinetics of the annealing process were successfully described by the Avrami nucleation and growth model showing that the annealing process was diffusion controlled and one dimensional. The activation energy for the solid-state transformation was 175 kJ/mol, which was similar to the activation energy of Pd-Cu bulk interdiffusion. Furthermore, the Avrami model was able to successfully describe the changes in permeance and activation energy observed in Pd/Cu alloy membranes during characterization as they were annealed at high temperatures.

  7. Single-crystalline CuGeO{sub 3} nanorods: Synthesis, characterization and properties

    SciTech Connect (OSTI)

    Wang, Fangfang; Xing, Yan; Su, Zhongmin; Song, Shuyan

    2013-07-15

    Graphical abstract: - Highlights: Single crystalline CuGeO{sub 3} nanorods were prepared via a hydrothermal route. The material exhibits greatly enhanced activity in photocatalytic degradation of dyes. The magnetic susceptibility measurements indicate spin-Peierls transition properties. CuGeO{sub 3} nanorods may be of potential application in future integrated optical devices. - Abstract: Single crystalline CuGeO{sub 3} nanorods with a diameter of 2035 nm and a length up to 1 ?m have been prepared via a facile hydrothermal route with the assistance of ethylenediamine. Some influencing factors such as the reaction time, reaction temperature, the volume of ethylenediamine were revealed to play crucial roles in the formation of the CuGeO{sub 3} nanorods. A possible growth mechanism was proposed based on the experimental results. Significantly, this is the first time that CuGeO{sub 3} was used as a photocatalyst for organic pollutant degradation under UV light irradiation. The reaction constant (k) of CuGeO{sub 3} nanorods was five times that of the sample prepared by solid-state reaction under UV light irradiation. Additionally, the optical and magnetic properties of CuGeO{sub 3} nanorods were systematically studied.

  8. In situ visualization of metallurgical reactions in nanoscale Cu/Sn diffusion couples

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Yin, Qiyue; Stach, Eric A.; Gao, Fan; Zhou, Guangwen; Gu, Zhiyong

    2015-02-10

    The Cu–Sn metallurgical soldering reaction in two-segmented Cu–Sn nanowires is visualized by in-situ transmission electron microscopy. By varying the relative lengths of Cu and Sn segments, we show that the metallurgical reaction starts at ~ 200 ° with the formation of a Cu–Sn solid solution for the Sn/Cu length ratio smaller than 1:5 while the formation of Cu–Sn intermetallic compounds (IMCs) for larger Sn/Cu length ratios. Upon heating the nanowires up to ~ 500 °C, two phase transformation pathways occur, η-Cu₆Sn₅ → ε-Cu₃Sn → δ-Cu₄₁Sn₁₁ for nanowires with a long Cu segment and η-Cu₆Sn₅ → ε-Cu₃Sn → γ-Cu₃Sn with amore » short Cu segment. The dynamic in situ TEM visualization of the evolution of Kirkendall voids demonstrates that Cu diffuses faster both in Sn and IMCs than that of Sn in Cu₃ and IMCs, which is the underlying cause of the dependence of the IMC formation and associated phase evolution on the relative lengths of the Cu and Sn segments.« less

  9. Thermal chemistry of the Cu-KI5 atomic layer deposition precursor on a copper surface

    SciTech Connect (OSTI)

    Ma, Qiang; Zaera, Francisco

    2015-01-01

    The thermal chemistry of a Cu(I) ketoiminate complex, Cu-KI5, resulting from the modification of the known Air Products CupraSelect{sup } copper CVD precursor Cu(hfac)(tmvs) designed to tether the two ligands via an isopropoxide linker, was studied under ultrahigh vacuum on a Cu(110) single-crystal surface by using a combination of temperature programmed desorption (TPD) and x-ray photoelectron spectroscopy. Adsorption at low temperatures was determined to take place via the displacement of the vinyl ligand by the surface. Molecular desorption was seen at 210?K, and the evolution of Cu(II)-KI5{sub 2} was established to take place at 280?K, presumably from a disproportionation reaction that also leads to the deposition of Cu(0). Other sets of desorption products were seen at 150, 250, and 430?K, all containing copper atoms and small organic moieties with molecular masses below 100 amu. The latter TPD peak in particular indicates significant fragmentation of the ligands, likely at the CN bond that holds the vinylsilane-isopropoxide moiety tethered to the ketoimine fragment, and possibly also at the union between the vinylsilane and the alkoxide linker. The 430?K temperature measured for this chemistry may set an upper limit for clean Cu film deposition, but since reactivity on the surface was also found to be inhibited at higher surface coverages, it may be delayed to higher temperatures under atomic layer deposition conditions.

  10. Characterization and device performance of (AgCu)(InGa)Se2 absorber layers

    SciTech Connect (OSTI)

    Hanket, Gregory; Boyle, Jonathan H.; Shafarman, William N.

    2009-06-08

    The study of (AgCu)(InGa)Se2 absorber layers is of interest in that Ag-chalcopyrites exhibit both wider bandgaps and lower melting points than their Cu counterparts. (AgCu)(InGa)Se2 absorber layers were deposited over the composition range 0 < Ag/(Ag+Cu) < 1 and 0.3 < Ga/(In+Ga) < 1.0 using a variety of elemental co-evaporation processes. Films were found to be singlephase over the entire composition range, in contrast to prior studies. Devices with Ga content 0.3 < Ga/(In+Ga) <0.5 tolerated Ag incorporation up to Ag/(Ag+Cu) = 0.5 without appreciable performance loss. Ag-containing films with Ga/(In+Ga) = 0.8 showed improved device characteristics over Cu-only control samples, in particular a 30-40% increase in short-circuit current. An absorber layer with composition Ag/(Ag+Cu) = 0.75 and Ga/(In+Ga) = 0.8 yielded a device with VOC = 890 mV, JSC = 20.5mA/cm2, fill factor = 71.3%, and ? = 13.0%.

  11. Performance evaluation of ZnO–CuO hetero junction solid state room temperature ethanol sensor

    SciTech Connect (OSTI)

    Yu, Ming-Ru; Suyambrakasam, Gobalakrishnan; Wu, Ren-Jang; Department of Nanotechnology, School of Interdisciplinary Courses, Noorul Islam Centre for Higher Education, Noorul Islam University, Kumaracoil 629180, Tamil Nadu ; Chavali, Murthy; Department of Applied Chemistry, Providence University, 200 Chungchi Road, Shalu, Taichung Hsien 433, Taiwan, R.O.C

    2012-07-15

    Graphical abstract: Sensor response (resistance) curves of time were changed from 150 ppm to 250 ppm alcohol concentration of ZnO–CuO 1:1. The response and recovery times were measured to be 62 and 83 s, respectively. The sensing material ZnO–CuO is a high potential alcohol sensor which provides a simple, rapid and highly sensitive alcohol gas sensor operating at room temperature. Highlights: ► The main advantages of the ethanol sensor are as followings. ► Novel materials ZnO–CuO ethanol sensor. ► The optimized ZnO–CuO hetero contact system. ► A good sensor response and room working temperature (save energy). -- Abstract: A semiconductor ethanol sensor was developed using ZnO–CuO and its performance was evaluated at room temperature. Hetero-junction sensor was made of ZnO–CuO nanoparticles for sensing alcohol at room temperature. Nanoparticles were prepared by hydrothermal method and optimized with different weight ratios. Sensor characteristics were linear for the concentration range of 150–250 ppm. Composite materials of ZnO–CuO were characterized using X-ray diffraction (XRD), temperature-programmed reduction (TPR) and high-resolution transmission electron microscopy (HR-TEM). ZnO–CuO (1:1) material showed maximum sensor response (S = R{sub air}/R{sub alcohol}) of 3.32 ± 0.1 toward 200 ppm of alcohol vapor at room temperature. The response and recovery times were measured to be 62 and 83 s, respectively. The linearity R{sup 2} of the sensor response was 0.9026. The sensing materials ZnO–CuO (1:1) provide a simple, rapid and highly sensitive alcohol gas sensor operating at room temperature.

  12. Magnetic Dipole Moment of {sup 57,59}Cu Measured by In-Gas-Cell Laser Spectroscopy

    SciTech Connect (OSTI)

    Cocolios, T. E.; Andreyev, A. N.; Bastin, B.; Bree, N.; Buescher, J.; Elseviers, J.; Gentens, J.; Huyse, M.; Kudryavtsev, Yu.; Pauwels, D.; Van den Bergh, P.; Van Duppen, P.; Sonoda, T.

    2009-09-04

    For the first time, in-gas-cell laser spectroscopy study of the {sup 57,59,63,65}Cu isotopes has been performed using the 244.164 nm optical transition from the atomic ground state of copper. The nuclear magnetic dipole moments for {sup 57,59,65}Cu relative to that of {sup 63}Cu have been extracted. The new value for {sup 57}Cu of mu({sup 57}Cu)=+2.582(7)mu{sub N} is in strong disagreement with the previous literature value but in good agreement with recent theoretical and systematic predictions.

  13. Crystal structure and magnetic properties of NaCu{sup II}[(Cu{sup II}{sub 3}O)(PO{sub 4}){sub 2}Cl

    SciTech Connect (OSTI)

    Jin Tengteng; Liu Wei; Chen Shuang; Prots, Yurii; Schnelle, Walter; Zhao Jingtai; Kniep, Ruediger; Hoffmann, Stefan

    2012-08-15

    A new copper(II) oxide phosphate chloride, NaCu{sup II}[(Cu{sup II}{sub 3}O)(PO{sub 4}){sub 2}Cl], has been synthesized by flux synthesis. Single-crystal X-ray diffraction data show that the title compound crystallizes in the monoclinic system, space group P2{sub 1}/c (No. 14), with lattice parameters a=8.392(2) A, b=6.3960(10) A, c=16.670(2) A, {beta}=109.470(10) Degree-Sign , V=843.6(3) A{sup 3}, Z=4. The crystal structure is characterized by a complex chain of copper-centered polyhedra running along [0 1 0] which are connected by phosphate tetrahedra. The resulting three-dimensional polyhedra framework exhibits channels filled by additional copper and sodium atoms. Field and temperature dependent measurements of the specific heat and the magnetic susceptibility reveal low-dimensional magnetic behavior. The compound starts to decompose at 700 K under release of oxygen and evaporation of Cu{sup I}Cl as shown by simultaneous thermogravimetry and mass spectrometry. - Graphical abstract: The crystal structure of the new copper(II) phosphate chloride, NaCu{sup II}[(Cu{sup II}{sub 3}O)(PO{sub 4}){sub 2}Cl], exhibits linear chains of copper tetrahedra which show low-dimensional magnetic behavior proven by specific heat and magnetic susceptibility measurements. Highlights: Black-Right-Pointing-Pointer A new copper(II) oxide phosphate chloride, NaCu{sup II}[(Cu{sup II}{sub 3}O)(PO{sub 4}){sub 2}Cl], has been synthesized by flux synthesis. Black-Right-Pointing-Pointer The crystal structure comprises chains of Cu{sub 4}O tetrahedra. Black-Right-Pointing-Pointer Low-dimensional behavior has been proven by magnetic and specific heat measurements. Black-Right-Pointing-Pointer On heating, Cu{sup I}Cl and oxygen are released shown by simultaneous thermogravimetry and mass spectrometry.

  14. Phosphorescence quenching by mechanical stimulus in CaZnOS:Cu

    SciTech Connect (OSTI)

    Tu, Dong; Kamimura, Sunao; Xu, Chao-Nan; Fujio, Yuki; Sakata, Yoshitaro; Ueno, Naohiro

    2014-07-07

    We have found that phosphorescence intensity of CaZnOS:Cu decreased visibly under an applied load. This mechanical quenching (MQ) of phosphorescence in CaZnOS:Cu corresponded to the mechanical stimuli. We have thus demonstrated that the MQ of CaZnOS:Cu could be used for visualizing stress distributions in practical applications. We propose that MQ arises from non-radiative recombination due to electron-transfer from trap levels to non-radiative centers as a result of the mechanical load.

  15. Atomic-scale studies on the effect of boundary coherency on stability in twinned Cu

    SciTech Connect (OSTI)

    Niu, Rongmei; Han, Ke Su, Yi-Feng; Salters, Vincent J.

    2014-01-06

    The stored energy and hardness of nanotwinned (NT) Cu are related to interaction between dislocations and (111)-twin boundaries (TBs) studied at atomic scales by high-angle annular dark-field scanning transmission electron microscope. Lack of mobile dislocations at coherent TBs (CTBs) provides as-deposited NT Cu a rare combination of stability and hardness. The introduction of numerous incoherent TBs (ITBs) reduces both the stability and hardness. While storing more energy in their ITBs than in the CTBs, deformed NT Cu also exhibits high dislocation density and TB mobility and therefore has increased the driving force for recovery, coarsening, and recrystallization.

  16. Structural evolution in Ti-Cu-Ni metallic glasses during heating

    SciTech Connect (OSTI)

    Gargarella, P.; Pauly, S.; Stoica, M.; Khn, U.; Vaughan, G.; Afonso, C. R. M.; Eckert, J.

    2015-01-01

    The structural evolution of Ti{sub 50}Cu{sub 43}Ni{sub 7} and Ti{sub 55}Cu{sub 35}Ni{sub 10} metallic glasses during heating was investigated by in-situ synchrotron X-ray diffraction. The width of the most intense diffraction maximum of the glassy phase decreases slightly during relaxation below the glass transition temperature. Significant structural changes only occur above the glass transition manifesting in a change in the respective peak positions. At even higher temperatures, nanocrystals of the shape memory B2-Ti(Cu,Ni) phase precipitate, and their small size hampers the occurrence of a martensitic transformation.

  17. Complex catalytic behaviors of CuTiOx mixed-oxide during CO oxidation

    Office of Scientific and Technical Information (OSTI)

    (Journal Article) | SciTech Connect Complex catalytic behaviors of CuTiOx mixed-oxide during CO oxidation Citation Details In-Document Search This content will become publicly available on September 21, 2016 Title: Complex catalytic behaviors of CuTiOx mixed-oxide during CO oxidation Mixed metal oxides have attracted considerable attention in heterogeneous catalysis due to the unique stability, reactivity, and selectivity. Here, the activity and stability of the CuTiOx monolayer film

  18. Controlling superconductivity in La2-xSrxCuO4+δ by ozone and vacuum

    Office of Scientific and Technical Information (OSTI)

    annealing (Journal Article) | SciTech Connect Controlling superconductivity in La2-xSrxCuO4+δ by ozone and vacuum annealing Citation Details In-Document Search Title: Controlling superconductivity in La2-xSrxCuO4+δ by ozone and vacuum annealing In this study we performed a series of ozone and vacuum annealing experiments on epitaxial La2-xSrxCuO4+δ thin films. The transition temperature after each annealing step has been measured by the mutual inductance technique. The relationship

  19. Y-Ba-Cu-O films prepared by a paint-on method

    SciTech Connect (OSTI)

    Shih, I.; Qiu, C.X.

    1988-02-29

    Polycrystalline films of Y-Ba-Cu-O with a thickness of about 20--40 ..mu..m have been prepared on alumina substrates using a paint-on method. The liquid source used was obtained by mixing powder of Y/sub 2/O/sub 3/, BaCO/sub 3/, and CuO in liquid triethanolamine. Several Y-Ba-Cu-O films with an onset temperature of about 100 K and a zero resistance temperature of 85 K have been obtained after a short heat treatment at 1000 /sup 0/C in flowing O/sub 2/.

  20. Mixed-sputter deposition of Ni-Ti-Cu shape memory films

    SciTech Connect (OSTI)

    Krulevitch, P.; Ramsey, P.B.; Makowiecki, D.M.; Lee, A.P.; Northrup, M.A.; Johnson, G.C.

    1994-05-01

    Ni-Ti-Cu shape memory films were mixed-sputter deposited from separate nickel, titanium, and copper targets, providing increased compositional flexibility. Shape memory characteristics, examined for films with 7 at. % Cu and 41--51 at. % Tl, were determined with temperature controlled substrate curvature measurements, and microstructure was studied with transmission electron microscopy. The Ni-Ti-Cu films were found to have shape memory properties comparable to bulk materials, with transformation temperatures between 20 and 62{degree}C, a 10--13{degree}C hysteresis, and up to 330 MPa recoverable stress.

  1. The effect of Cu content on the structure of Ni{sub 1-x}Cu{sub x}Fe{sub 2}O{sub 4} spinels

    SciTech Connect (OSTI)

    Tan, Xiaoyan; The Institute of Applied Chemistry, Central South University of Forestry and Technology, Changsha, Hunan 412006 ; Li, Guiying; Zhao, Ying; Hu, Changwei

    2009-12-15

    A series of Ni{sub 1-x}Cu{sub x}Fe{sub 2}O{sub 4} (0 {<=} x {<=} 0.5) spinels were synthesized employing sol-gel combustion method at 400 {sup o}C. The decomposition process was monitored by thermal analysis, and the synthesized nanocrystallites were characterized by X-ray diffraction, transmission electron microscopy, infra-red and X-ray photoelectron spectroscopy. The decomposition process and ferritization occur simultaneously over the temperature range from 280 {sup o}C to 350 {sup o}C. TEM indicates the increase of lattice parameter and particle size with the increase of copper content in accordance with the XRD analysis. Cu{sup 2+} can enter the cubic spinel phase and occupy preferentially the B-sites within x = 0.3, and redundant copper forms CuO phase separately. A broadening of the O 1s region increases with the increment of copper content compared to pure NiFe{sub 2}O{sub 4}, showing different surface oxygen species from the spinel and CuO. Cu{sup 2+} substitution favors the occupancy of A-sites by Fe{sup 3+}.

  2. Effect of Cu2+ Activation on Interfacial Water Structure at the Sphalerite Surface as Studied by Molecular Dynamics Simulation

    SciTech Connect (OSTI)

    Jin, Jiaqi; Miller, Jan D.; Dang, Liem X.; Wick, Collin D.

    2015-12-10

    In the first part of this paper, an experimental contact angle study of the fresh and Cu2+ activated sphalerite-ZnS surface as well as the covellite-CuS (001) surface is reported describing the increased hydrophobic character of the surface during Cu2+ activation. In addition to these experimental results, the fresh sphalerite-ZnS (110), copper-zinc sulfide-CuZnS2 (110), villamaninite- CuS2 (100), and covellite-CuS (001) surfaces were examined using Molecular Dynamics Simulation (MDS). Our MDS results on the behavior of interfacial water at the fresh sphalerite-ZnS (110), copper-zinc sulfide-CuZnS2 (110), villamaninite-CuS2 (100), and covellite-CuS (001) surfaces include simulated contact angles, water number density distribution, water dipole orientation, water residence time, and hydrogen-bonding considerations. The copper content at the Cu2+ activated sphalerite surface seems to account for the increased hydrophobicity as revealed by both experimental and MD simulated contact angle measurements. The relatively greater hydrophobic character developed at the Cu2+ activated sphalerite surface and at the copper-zinc sulfide surface has been described by MDS, based on the structure of interfacial water and its dynamic properties. L.X.D. acknowledges funding from the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences, and Biosciences.

  3. A Theoretical Study of Methanol Synthesis from CO(2) Hydrogenation on Metal-doped Cu(111) Surfaces

    SciTech Connect (OSTI)

    Liu P.; Yang, Y.; White, M.G.

    2012-01-12

    Density functional theory (DFT) calculations and Kinetic Monte Carlo (KMC) simulations were employed to investigate the methanol synthesis reaction from CO{sub 2} hydrogenation (CO{sub 2} + 3H{sub 2} {yields} CH{sub 3}OH + H{sub 2}O) on metal-doped Cu(111) surfaces. Both the formate pathway and the reverse water-gas shift (RWGS) reaction followed by a CO hydrogenation pathway (RWGS + CO-Hydro) were considered in the study. Our calculations showed that the overall methanol yield increased in the sequence: Au/Cu(111) < Cu(111) < Pd/Cu(111) < Rh/Cu(111) < Pt/Cu(111) < Ni/Cu(111). On Au/Cu(111) and Cu(111), the formate pathway dominates the methanol production. Doping Au does not help the methanol synthesis on Cu(111). Pd, Rh, Pt, and Ni are able to promote the methanol production on Cu(111), where the conversion via the RWGS + CO-Hydro pathway is much faster than that via the formate pathway. Further kinetic analysis revealed that the methanol yield on Cu(111) was controlled by three factors: the dioxomethylene hydrogenation barrier, the CO binding energy, and the CO hydrogenation barrier. Accordingly, two possible descriptors are identified which can be used to describe the catalytic activity of Cu-based catalysts toward methanol synthesis. One is the activation barrier of dioxomethylene hydrogenation, and the other is the CO binding energy. An ideal Cu-based catalyst for the methanol synthesis via CO{sub 2} hydrogenation should be able to hydrogenate dioxomethylene easily and bond CO moderately, being strong enough to favor the desired CO hydrogenation rather than CO desorption but weak enough to prevent CO poisoning. In this way, the methanol production via both the formate and the RWGS + CO-Hydro pathways can be facilitated.

  4. Measurement of cross sections for the Cu-63(alpha,gamma)Ga-67...

    Office of Scientific and Technical Information (OSTI)

    Title: Measurement of cross sections for the Cu-63(alpha,gamma)Ga-67 reaction from 5.9-8.7 MeV Authors: Basunia, M S ; Norman, E B ; Shugart, H A ; Smith, A R ; Dolinski, M J ; ...

  5. Complex catalytic behaviors of CuTiOx mixed-oxide during CO oxidation...

    Office of Scientific and Technical Information (OSTI)

    Complex catalytic behaviors of CuTiOx mixed-oxide during CO oxidation Citation Details ... This content will become publicly available on September 21, 2016 Title: Complex catalytic ...

  6. Measurement of Cross Sections for the 63Cu(alpha,gamma)67Ga Reaction...

    Office of Scientific and Technical Information (OSTI)

    Title: Measurement of Cross Sections for the 63Cu(alpha,gamma)67Ga Reaction from 5.9-8.7 MeV Authors: Basunia, M S ; Norman, E B ; Shugart, H A ; Smith, A R ; Dolinski, M J ; ...

  7. Non-Equilibrium Superconductivity and Quasiparticle Dynamics in YBaCuO

    SciTech Connect (OSTI)

    Siders, J.L.W.; Jacobs, R.N.; Siders, C.W.; Trugman, S.A.; Taylor, A.J.

    1999-05-21

    The authors use optical pump, coherent terahertz probe spectroscopy to transiently excite nonequilibrium populations of quasiparticles in YBa{sub 2}Cu{sub 3}O{sub 7.{delta}} and monitor, with picosecond resolution, the superfluid and quasiparticle dynamics.

  8. Supported Au-CuO Catalysts for Low Temperature CO Oxidation

    Broader source: Energy.gov [DOE]

    Catalytic properties of Au-CuOx/SiO2 are investigated in removing pollutants from simulated automotive exhaust to meet an increasing demand for high emissions control at low temperatures.

  9. Broken Symmetry in the Pseudogap State of YBa2Cu3O6+x (Technical...

    Office of Scientific and Technical Information (OSTI)

    Title: Broken Symmetry in the Pseudogap State of YBa2Cu3O6+x Authors: Ramshaw, Brad 1 + Show Author Affiliations Los Alamos National Laboratory Los Alamos National Laboratory ...

  10. Method of synthesizing and growing copper-indium-diselenide (CuInSe.sub.2) crystals

    DOE Patents [OSTI]

    Ciszek, Theodore F.

    1987-01-01

    A process for preparing CuInSe.sub.2 crystals includes melting a sufficient quantity of B.sub.2 O.sub.3 along with stoichiometric quantities of Cu, In, and Se in a crucible in a high pressure atmosphere of inert gas to encapsulate the CuInSe.sub.2 melt and confine the Se to the crucible. Additional Se in the range of 1.8 to 2.2 percent over the stoichiometric quantity is preferred to make up for small amounts of Se lost in the process. The crystal is grown by inserting a seed crystal through the B.sub.2 O.sub.3 encapsulate into contact with the CuInSe.sub.2 melt and withdrawing the seed upwardly to grow the crystal thereon from the melt.

  11. Method of synthesizing and growing copper-indium-diselenide (CuInSe/sub 2/) crystals

    DOE Patents [OSTI]

    Ciszek, T.F.

    1984-11-29

    A process for preparing CuInSe/sub 2/ crystals includes melting a sufficient quantity of B/sub 2/O/sub 2/ along with stochiometric quantities of Cu, In, and Se in a crucible in a high-pressure atmosphere of inert gas to encapsulate the CuInSe/sub 2/ melt and confine the Se to the crucible. Additional Se in the range of 1.8 to 2.2% over the stochiometric quantity is preferred to make up for small amounts of Se lost in the process. The melt can then be cooled slowly to form the crystal as direct solidification, or the crystal can be grown by inserting a seed crystal through the B/sub 2/O/sub 3/ encapsulate into contact with the CuInSe/sub 2/ melt and withdrawing the seed upwardly to grow the crystal thereon from the melt.

  12. Understanding the Deactivation Mechanisms of Cu/Zeolite SCR Catalysts in Diesel Application

    Office of Energy Efficiency and Renewable Energy (EERE)

    To understand the durability of Cu/Zeolite urea-SCR catalysts in diesel applications, the effects of engine and lab aging on catalyst reactivity and material properties were investigated.

  13. Magnetization of underdoped YBa 2 Cu 3 O y above the irreversibility...

    Office of Scientific and Technical Information (OSTI)

    Title: Magnetization of underdoped YBa 2 Cu 3 O y above the irreversibility field Authors: Yu, Jing Fei ; Ramshaw, B. J. ; Kokanovi, I. ; Modic, K. A. ; Harrison, N. ; Day, James ...

  14. Structural and thermal properties of nanocrystalline CuO synthesized by reactive magnetron sputtering

    SciTech Connect (OSTI)

    Verma, M.; Gupta, V. K.; Gautam, Y. K.; Dave, V.; Chandra, R.

    2014-01-28

    Recent research has shown immense application of metal oxides like CuO, MgO, CaO, Al{sub 2}O{sub 3}, etc. in different areas which includes chemical warfare agents, medical drugs, magnetic storage media and solar energy transformation. Among the metal oxides, CuO nanoparticles are of special interest because of their excellent gas sensing and catalytic properties. In this paper we report structural and thermal properties of CuO synthesized by reactive magnetron DC sputtering. The synthesized nanoparticles were characterized by X-ray diffractometer. The XRD result reveals that as DC power increased from 30W to 80W, size of the CuO nanoparticles increased. The same results have been verified through TEM analysis. Thermal properties of these particles were studied using thermogravimetry.

  15. Ordered structures in YBa/sub 2/Cu/sub 3/O/sub 7-y/, La/sub 2-x/Sr/sub x/CuO/sub 4-par. delta/ and related perovskites

    SciTech Connect (OSTI)

    Mitchell, T.E.; Roy, T.; Fisk, Z.; Smith, J.L.

    1988-01-01

    Electron microscopy and electron diffraction studies have been performed on the superconducting oxides YBa/sub 2/Cu/sub 3/O/sub 7-y/, GdBa/sub 2/Cu/sub 3/O/sub 7-y/ and La/sub 2-x/Sr/sub x/CuO/sub 4-par. delta/ as well as the related perovskites La/sub 2/CuO/sub 4/, Eu/sub 2/CuO/sub 4/ and Gd/sub 2/CuO/sub 4/. Extra reflections are commonly observed in all the cases. For example, in the 123 compounds, in situ heating leads to transformations from orthorhombic to tetragonal with a loss of twin structure; on cooling the oxygen vacancies re-order in the basal plane to give 1/3(100)* or 1/4(110)* diffraction spots. In tetragonal Eu/sub 2/CuO/sub 4/ and Gd/sub 2/CuO/sub 4/, the (001) diffraction patterns often have extra spots at 1/2(110)* or at 1/4(110)* positions. Extra spots are also observed in La/sub 2/CuO/sub 4/ (orthorhombic) but this is probably due to the space group being primitive rather than centered. These observations are discussed in terms of the ordering of oxygen vacancies in the Cu-O planes of the various perovskite structures. 6 figs.

  16. CU-CBR-1-I Wholesale Power Rate Schedule | Department of Energy

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

    CBR-1-I Wholesale Power Rate Schedule CU-CBR-1-I Wholesale Power Rate Schedule Area: Big Rivers and Henderson, KY System: CU This rate schedule shall be available to Big Rivers Electric Corporation and includes the City of Henderson, Kentucky. This rate schedule shall be applicable to electric capacity and energy available from the Dale Hollow, Center Hill, Wolf Creek, Cheatham, Old Hickory, Barkley, J. Percy Priest, and Cordell Hull Projects (all of such projects being hereinafter called

  17. CU-CC-1-J Wholesale Power Rate Schedule | Department of Energy

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

    CC-1-J Wholesale Power Rate Schedule CU-CC-1-J Wholesale Power Rate Schedule Area: Duke Energy Progress, Western Division System: CU This rate schedule shall be available to public bodies and cooperatives served through the facilities of Duke Energy Progress (formerly known as Carolina Power & Light Company), Western Division (hereinafter called the Customers). This rate schedule shall be applicable to electric capacity and energy available from the Dale Hollow, Center Hill, Wolf Creek,

  18. CU-CEK-1-I Wholesale Power Rate Schedule | Department of Energy

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

    CEK-1-I Wholesale Power Rate Schedule CU-CEK-1-I Wholesale Power Rate Schedule Area: East Kentucky System: CU This rate schedule shall be available to East Kentucky Power Cooperative (hereinafter called the Customer). This rate schedule shall be applicable to electric capacity and energy available from the Dale Hollow, Center Hill, Wolf Creek, Cheatham, Old Hickory, Barkley, J. Percy Priest, and Cordell Hull Projects (all of such projects being hereinafter called collectively the

  19. CU-CK-1-I Wholesale Power Rate Schedule | Department of Energy

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

    CK-1-I Wholesale Power Rate Schedule CU-CK-1-I Wholesale Power Rate Schedule Area: Kentucky Utilities System: CU This rate schedule shall be available to public bodies served through the facilities of Kentucky Utilities Company, (hereinafter called the Customers.) This rate schedule shall be applicable to electric capacity and energy available from the Dale Hollow, Center Hill, Wolf Creek, Cheatham, Old Hickory, Barkley, J. Percy Priest, and Cordell Hull Projects (all of such projects being

  20. CU-CM-1-I Wholesale Power Rate Schedule | Department of Energy

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

    CM-1-I Wholesale Power Rate Schedule CU-CM-1-I Wholesale Power Rate Schedule Area: MEAM, MDEA, and SMEPA System: CU This rate schedule shall be available to the South Mississippi Electric Power Association, Municipal Energy Agency of Mississippi, and Mississippi Delta Energy Agency. This rate schedule shall be applicable to electric capacity and energy available from the Dale Hollow, Center Hill, Wolf Creek, Cheatham, Old Hickory, Barkley, J. Percy Priest, and Cordell Hull Projects (all of such

  1. CU-CSI-1-I Wholesale Power Rate Schedule | Department of Energy

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

    CSI-1-I Wholesale Power Rate Schedule CU-CSI-1-I Wholesale Power Rate Schedule Area: Southern Illinois System: CU This rate schedule shall be available to Southern Illinois Power Cooperative (hereinafter the Customer). This rate schedule shall be applicable to electric capacity and energy available from the Dale Hollow, Center Hill, Wolf Creek, Cheatham, Old Hickory, Barkley, J. Percy Priest, and Cordell Hull Projects (all of such projects being hereinafter called collectively the

  2. CU-CTV-1-I Wholesale Power Rate Schedule | Department of Energy

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

    CTV-1-I Wholesale Power Rate Schedule CU-CTV-1-I Wholesale Power Rate Schedule Area: Tennessee Valley Authority System: CU This rate schedule shall be available to the Tennessee Valley Authority (hereinafter called TVA). This rate schedule shall be applicable to electric capacity and energy generated at the Dale Hollow, Center Hill, Wolf Creek, Old Hickory, Cheatham, Barkley, J. Percy Priest, and Cordell Hull Projects (all of such projects being hereafter called collectively the "Cumberland

  3. CU-Replacement-3 Wholesale Power Rate Schedule | Department of Energy

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

    Replacement-3 Wholesale Power Rate Schedule CU-Replacement-3 Wholesale Power Rate Schedule Area: Virginia, North Carolina, Tennessee, Georgia, Alabama, Mississippi, Kentucky, southern Illinois System: CU This rate schedule shall be available to public bodies and cooperatives ( any one of whom is hereinafter called the Customer) in Virginia, North Carolina, Tennessee, Georgia, Alabama, Mississippi, Kentucky and southern Illinois to whom power is provided pursuant to contracts between the

  4. Understanding NOx SCR Mechanism and Activity on Cu/Chabazite Structures throughout the Catalyst Life Cycle

    SciTech Connect (OSTI)

    Ribeiro, Fabio; Delgass, Nick; Gounder, Rajmani; Schneider, William F.; Miller, Jeff; Yezerets, Aleksey; McEwen, Jean-Sabin; Peden, Charles HF; Howden, Ken

    2014-12-09

    Oxides of nitrogen (NOx) compounds contribute to acid rain and photochemical smog and have been linked to respiratory ailments. NOx emissions regulations continue to tighten, driving the need for high performance, robust control strategies. The goal of this project is to develop a deep, molecular level understanding of the function of Cu-SSZ-13 and Cu-SAPO-34 materials that catalyze the SCR of NOx with NH3.

  5. Potassium-induced effect on structure and chemical activity of CuxO/Cu(111)

    Office of Scientific and Technical Information (OSTI)

    (x≤2) surface: A combined scanning tunneling microscopy and density functional theory study (Journal Article) | SciTech Connect Potassium-induced effect on structure and chemical activity of CuxO/Cu(111) (x≤2) surface: A combined scanning tunneling microscopy and density functional theory study Citation Details In-Document Search This content will become publicly available on October 16, 2016 Title: Potassium-induced effect on structure and chemical activity of CuxO/Cu(111) (x≤2)

  6. Investigation of Sulfur Deactivation on Cu/Zeolite SCR Catalysts in Diesel

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

    Application | Department of Energy Investigation of Sulfur Deactivation on Cu/Zeolite SCR Catalysts in Diesel Application PDF icon deer09_cheng.pdf More Documents & Publications Deactivation Mechanisms of Base Metal/Zeolite Urea Selective Catalytic Reduction Materials Sulfur Effect and Performance Recovery of a DOC + CSF + Cu-Zeolite SCR System Deactivation Mechanisms of Base Metal/Zeolite Urea Selective Catalytic Reduction Materials, and Development of Zeolite-Based Hydrocarbon Adsorber

  7. Thin-film polycrystalline n-ZnO/p-CuO heterojunction

    SciTech Connect (OSTI)

    Lisitski, O. L.; Kumekov, M. E.; Kumekov, S. E. Terukov, E. I.

    2009-06-15

    Results of X-ray diffraction and spectral-optical studies of n-ZnO and p-CuO films deposited by gas-discharge sputtering with subsequent annealing are presented. It is shown that, despite the difference in the crystal systems, the polycrystallinity of n-ZnO and p-CuO films enables fabrication of a heterojunction from this pair of materials.

  8. Doping Cu{sub 2}O in Electrolyte Solution: Dopant Incorporation, Atomic Structures and Electrical Properties

    SciTech Connect (OSTI)

    Tao, Meng; Zhang, Qiming

    2013-11-24

    We have pursued a number of research activities between April 2010 and April 2011:  A detailed study on n-type doping in Cu2O by Br;  An analysis of natural resource limitations to terawatt-scale solar cells;  Attempt to achieve a 1.4-eV direct band gap in Ni sulfides (NiSx);  First-principles studies of doping in Cu2O and electronic structures of NiSx.

  9. Three-dimensional Dendritic Needle Network model with application to Al-Cu

    Office of Scientific and Technical Information (OSTI)

    directional solidification experiments (Journal Article) | SciTech Connect Journal Article: Three-dimensional Dendritic Needle Network model with application to Al-Cu directional solidification experiments Citation Details In-Document Search Title: Three-dimensional Dendritic Needle Network model with application to Al-Cu directional solidification experiments We present a three-dimensional (3D) extension of a previously proposed multi-scale Dendritic Needle Network (DNN) approach for the

  10. Metallic glass alloys of Zr, Ti, Cu and Ni

    DOE Patents [OSTI]

    Lin, Xianghong; Peker, Atakan; Johnson, William L.

    1997-01-01

    At least quaternary alloys form metallic glass upon cooling below the glass transition temperature at a rate less than 10.sup.3 K/s. Such alloys comprise titanium from 19 to 41 atomic percent, an early transition metal (ETM) from 4 to 21 atomic percent and copper plus a late transition metal (LTM) from 49 to 64 atomic percent. The ETM comprises zirconium and/or hafnium. The LTM comprises cobalt and/or nickel. The composition is further constrained such that the product of the copper plus LTM times the atomic proportion of LTM relative to the copper is from 2 to 14. The atomic percentage of ETM is less than 10 when the atomic percentage of titanium is as high as 41, and may be as large as 21 when the atomic percentage of titanium is as low as 24. Furthermore, when the total of copper and LTM are low, the amount of LTM present must be further limited. Another group of glass forming alloys has the formula (ETM.sub.1-x Ti.sub.x).sub.a Cu.sub.b (Ni.sub.1-y Co.sub.y).sub.c wherein x is from 0.1 to 0.3, y.cndot.c is from 0 to 18, a is from 47 to 67, b is from 8 to 42, and c is from 4 to 37. This definition of the alloys has additional constraints on the range of copper content, b.

  11. The magnetic structure of EuCu2Sb2

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Ryan, D. H.; Cadogan, J. M.; Anand, V. K.; Johnston, D. C.; Flacau, R.

    2015-05-06

    Antiferromagnetic ordering of EuCu2Sb2 which forms in the tetragonal CaBe2Ge2-type structure (space group P4/nmm #129) has been studied using neutron powder diffraction and 151Eu Mössbauer spectroscopy. The room temperature 151Eu isomer shift of –12.8(1) mm/s shows the Eu to be divalent, while the 151Eu hyperfine magnetic field (Bhf) reaches 28.7(2) T at 2.1 K, indicating a full Eu2+ magnetic moment. Bhf(T) follows a smoothmore » $$S=\\frac{7}{2}$$ Brillouin function and yields an ordering temperature of 5.1(1) K. Refinement of the neutron diffraction data reveals a collinear A-type antiferromagnetic arrangement with the Eu moments perpendicular to the tetragonal c-axis. As a result, the refined Eu magnetic moment at 0.4 K is 7.08(15) μB which is the full free-ion moment expected for the Eu2+ ion with $$S=\\frac{7}{2}$$ and a spectroscopic splitting factor of g = 2.« less

  12. Electrochemical synthesis of Nb3Sn coatings on Cu substrates

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Franz, S.; Barzi, E.; Turrioni, D.; Glionna, L.; Bestetti, M.

    2015-09-11

    This study aims at contributing to the development of superconducting Nb3Sn thin films for possible applications, as for instance in superconducting radio frequency (SRF) cavities. The synthesis of Nb-Sn coatings was carried out on copper substrates by electrodeposition from 1-Butyl-3-methylimidazolium chloride (BMIC) ionic liquids containing SnCl2 and NbCl5. Cyclic voltammetric curves were recorded to identify the reduction potentials of Nb and Sn ionic species. Electrodeposition was performed at 40 and 400 mA/cm2 and 130°C. The CV demonstrated that BMIC has a suitable potential window for co-deposition of Nb and Sn. The electrodeposited coatings showed a cubic Nb3Sn phase with (211)more » preferred orientation, a disordered orthorhombic NbSn2 phase and Sn-Cu phases. Film thickness was from 200 to 750 nm. These results suggest that electrodeposition of Nb-Sn coatings on copper substrates could be a suitable route to one day replace the current expensive Nb SRF cavities.« less

  13. Magnetic order tuned by Cu substitution in Fe1.1–zCuzTe

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Wen, Jinsheng; Xu, Zhijun; Xu, Guangyong; Lumsden, M. D.; Valdivia, P. N.; Bourret-Courchesne, E.; Gu, Genda; Lee, Dung-Hai; Tranquada, J. M.; Birgeneau, R. J.

    2012-07-02

    We study the effects of Cu substitution in Fe₁.₁Te, the nonsuperconducting parent compound of the iron-based superconductor, Fe₁₊yTe₁₋xSex, utilizing neutron scattering techniques. It is found that the structural and magnetic transitions, which occur at ~60 K without Cu, are monotonically depressed with increasing Cu content. By 10% Cu for Fe, the structural transition is hardly detectable, and the system becomes a spin glass below 22 K, with a slightly incommensurate ordering wave vector of (0.5–δ, 0, 0.5) with δ being the incommensurability of 0.02, and correlation length of 12 Å along the a axis and 9 Å along the cmore » axis. With 4% Cu, both transition temperatures are at 41 K, though short-range incommensurate order at (0.42, 0, 0.5) is present at 60 K. With further cooling, the incommensurability decreases linearly with temperature down to 37 K, below which there is a first-order transition to a long-range almost-commensurate antiferromagnetic structure. A spin anisotropy gap of 4.5 meV is also observed in this compound. Our results show that the weakly magnetic Cu has a large effect on the magnetic correlations; it is suggested that this is caused by the frustration of the exchange interactions between the coupled Fe spins.« less

  14. Enhanced thermoelectric performance in Cd doped CuInTe{sub 2} compounds

    SciTech Connect (OSTI)

    Cheng, N.; Liu, R.; Bai, S.; Shi, X. Chen, L.

    2014-04-28

    CuIn{sub 1?x}Cd{sub x}Te{sub 2} materials (x?=?0, 0.02, 0.05, and 0.1) are prepared using melting-annealing method and the highly densified bulk samples are obtained through Spark Plasma Sintering. The X-ray diffraction data confirm that nearly pure chalcopyrite structures are obtained in all the samples. Due to the substitution of Cd at In sites, the carrier concentration is greatly increased, leading to much enhanced electrical conductivity and power factor. The single parabolic band model is used to describe the electrical transport properties of CuInTe{sub 2} and the low temperature Hall mobility is also modeled. By combing theoretical model and experiment data, the optimum carrier concentration in CuInTe{sub 2} is proposed to explain the greatly enhanced power factors in the Cd doped CuInTe{sub 2}. In addition, the thermal conductivity is reduced by extra phonon scattering due to the atomic mass and radius fluctuations between Cd and In atoms. The maximum zTs are observed in CuIn{sub 0.98}Cd{sub 0.02}Te{sub 2} and CuIn{sub 0.9}Cd{sub 0.1}Te{sub 2} samples, which are improved by over 100% at room temperature and around 20% at 600?K.

  15. Complex catalytic behaviors of CuTiOx mixed-oxide during CO oxidation

    SciTech Connect (OSTI)

    Kim, Hyun You; Liu, Ping

    2015-09-21

    Mixed metal oxides have attracted considerable attention in heterogeneous catalysis due to the unique stability, reactivity, and selectivity. Here, the activity and stability of the CuTiOx monolayer film supported on Cu(111), CuTiOx/Cu(111), during CO oxidation was explored using density functional theory (DFT). The unique structural frame of CuTiOx is able to stabilize and isolate a single Cu+ site on the terrace, which is previously proposed active for CO oxidation. Furthermore, it is not the case, where the reaction via both the LangmuirHinshelwood (LH) and the Mars-van Krevelen (M-vK) mechanisms are hindered on such single Cu+ site. Upon the formation of step-edges, the synergy among Cu?+ sites, TiOx matrix, and Cu(111) is able to catalyze the reaction well. Depending on temperatures and partial pressure of CO and O2, the surface structure varies, which determines the dominant mechanism. In accordance with our results, the Cu?+ ion alone does not work well for CO oxidation in the form of single sites, while the synergy among multiple active sites is necessary to facilitate the reaction.

  16. Hydrodechlorination of 1,2-Dichloroethane Catalyzedby Dendrimer-Derived Pt-Cu/SiO2 Catalysts

    SciTech Connect (OSTI)

    Xie, Hong; Howe, Jane Y; Schwartz, Viviane; Monnier, J. R.; Williams, Christopher T.; Ploehn, Harry J.

    2008-01-01

    Dendrimer-metal-nanocomposites (DMNs) were used as precursors to prepare SiO2 supported monometallic Pt, Cu and bimetallic Pt-Cu catalysts with Pt/Cu atomic ratios of 1:1 (Pt50Cu50) and 1:3 (Pt25Cu75). After impregnation of these DMNs onto the support, the catalysts were thermally treated and activated following an optimized protocol. Scanning transmission electron microscopy (STEM) shows that the metal nanoparticles in dendrimer-derived SiO2-supported catalysts are smaller and have a more narrow size distribution than those in conventional catalysts prepared using corresponding metal salts via the wet impregnation method. Slow deactivation was observed for hydrodechlorination of 1,2-dichloroethane over monometallic Cu catalysts, which showed an activity about one to two orders of magnitude lower than that of the Pt-containing catalysts. Hydrodechlorination of 1,2-dichloroethane over Pt and Pt50Cu50 catalysts mainly produces ethane and the selectivity towards ethane increases with temperature. For Pt25Cu75 catalyst, the selectivity towards ethane decreases in favor of ethylene. The overall activity decreases with increasing Cu loading in the catalysts. Activity based on surface Pt sites suggests the formation of bi-functional surfaces in Pt25Cu75 catalyst favoring C-Cl bond scission on Cu sites and hydrogenation of intermediate .CH2CH2. on Pt sites. Furthermore, kinetic analyses suggest different reaction mechanisms for hydrodechlorination of 1,2-dichloroethane over Pt and Cu-enriched surfaces in the Pt-Cu bimetallic catalysts.

  17. Novel Approaches to Wide Bandgap CuInSe2 Based Absorbers

    SciTech Connect (OSTI)

    William N. Shafarman

    2011-04-28

    This project targeted the development of high performance wide bandgap solar cells based on thin film alloys of CuInSe2 to relax constraints on module design and enable tandem solar cell structures. This addressed goals of the Solar Energy Technologies Program for Next Generation PV to develop technology needed for higher thin film module efficiency as a means to reduce costs. Specific objectives of the research project were: 1) to develop the processes and materials required to improve the performance of wide bandgap thin film solar cells based on alloys of CuInSe2, and 2) to provide the fundamental science and engineering basis for the material, electronic, and device properties required to effectively apply these processes and materials to commercial manufacture. CuInSe2-based photovoltaics have established the highest efficiencies of the thin film materials at both the cell and module scales and are actively being scaled up to commercialization. In the highest efficiency cells and modules, the optical bandgap, a function of the CuInSe2-based alloy composition, is relatively low compared to the optimum match to the solar spectrum. Wider bandgap alloys of CuInSe2 produce higher cell voltages which can improve module performance and enable the development of tandem solar cells to boost the overall efficiency. A focus for the project was alloying with silver to form (AgCu)(InGa)Se2 pentenary thin films deposited by elemental co-evaporation which gives the broadest range of control of composition and material properties. This alloy has a lower melting temperature than Ag-free, Cu-based chalcopyrite compounds, which may enable films to be formed with lower defect densities and the (AgCu)(InGa)Se2 films give improved material properties and better device performance with increasing bandgap. A comprehensive characterization of optical, structural, and electronic properties of (AgCu)(InGa)Se2 was completed over the complete compositional range 0 ≤ Ga/(In+Ga) ≤ 1 and 0 ≤ Ag/(Ag+Cu) ≤ 1. Evidence of improved material quality includes reduced sub-bandgap optical absorption, sharper bandtails, and increased grain size with Ag addition. The Ag alloying was shown to increase the range of bandgaps over which solar cells can be fabricated without any drop-off in performance. With bandgap greater than 1.6 eV, in the range needed for tandem solar cells, (AgCu)(InGa)Se2 gave higher efficiency than other CuInSe2-based alloys. Using a simple single-stage co-evaporation process, a solar cell with 17.6% efficiency using a film with bandgap = 1.3 eV was achieved, demonstrating the viability of (AgCu)(InGa)Se2 for high efficiency devices. With a three-stage co-evaporation process for (AgCu)(InGa)Se2 deposition a device with efficiency = 13.0 % and VOC = 890 mV with JSC = 20.5 mA/cm2, FF = 71.3% was achieved. This surpasses the performance of other wide bandgap CuInSe2-based solar cells. Detailed characterization of the electronic properties of the materials and devices including the application of advanced admittance-based easements was completed.

  18. Synthesis and anti-bacterial activity of Cu, Ag and Cu-Ag alloy nanoparticles: A green approach

    SciTech Connect (OSTI)

    Valodkar, Mayur; Modi, Shefaly; Pal, Angshuman; Thakore, Sonal

    2011-03-15

    Research highlights: {yields} Synthesis of novel nanosized copper-silver alloys of different compositions. {yields} Completely green approach for synthesis of water soluble bimetallic nanoparticle. {yields} Interesting anti-bacterial activity of as synthesized metal and alloy nanoparticle. -- Abstract: Metallic and bimetallic nanoparticles of copper and silver in various proportions were prepared by microwave assisted chemical reduction in aqueous medium using the biopolymer, starch as a stabilizing agent. Ascorbic acid was used as the reducing agent. The silver and copper nanoparticles exhibited surface plasmon absorption resonance maxima (SPR) at 416 and 584 nm, respectively; while SPR for the Cu-Ag alloys appeared in between depending on the alloy composition. The SPR maxima for bimetallic nanoparticles changes linearly with increasing copper content in the alloy. Transmission electron micrograph (TEM) showed monodispersed particles in the range of 20 {+-} 5 nm size. Both silver and copper nanoparticles exhibited emission band at 485 and 645 nm, respectively. The starch-stabilized nanoparticles exhibited interesting antibacterial activity with both gram positive and gram negative bacteria at micromolar concentrations.

  19. Metallic glass alloys of Zr, Ti, Cu and Ni

    DOE Patents [OSTI]

    Lin, X.; Peker, A.; Johnson, W.L.

    1997-04-08

    At least quaternary alloys form metallic glass upon cooling below the glass transition temperature at a rate less than 10{sup 3} K/s. Such alloys comprise titanium from 19 to 41 atomic percent, an early transition metal (ETM) from 4 to 21 atomic percent and copper plus a late transition metal (LTM) from 49 to 64 atomic percent. The ETM comprises zirconium and/or hafnium. The LTM comprises cobalt and/or nickel. The composition is further constrained such that the product of the copper plus LTM times the atomic proportion of LTM relative to the copper is from 2 to 14. The atomic percentage of ETM is less than 10 when the atomic percentage of titanium is as high as 41, and may be as large as 21 when the atomic percentage of titanium is as low as 24. Furthermore, when the total of copper and LTM are low, the amount of LTM present must be further limited. Another group of glass forming alloys has the formula (ETM{sub 1{minus}x}Ti{sub x}){sub a} Cu{sub b} (Ni{sub 1{minus}y}Co{sub y}){sub c} wherein x is from 0.1 to 0.3, y{center_dot}c is from 0 to 18, a is from 47 to 67, b is from 8 to 42, and c is from 4 to 37. This definition of the alloys has additional constraints on the range of copper content, b. 2 figs.

  20. Nucleation and growth of oxide islands during the initial-stage oxidation of (100)Cu-Pt alloys

    SciTech Connect (OSTI)

    Luo, Langli; Zhou, Guangwen; Kang, Yihong; Yang, Judith C.

    2015-02-14

    The initial-stage oxidation of (100) Cu-Pt alloys has been examined by in situ environmental transmission electron microscopy and ex situ atomic force microscopy (AFM). It is shown that the oxidation proceeds via the nucleation and growth of Cu{sub 2}O islands that show dependence on the alloy composition and oxidation temperature. The kinetic measurements on the oxide nucleation reveal that both the nucleation density and surface coverage of Cu{sub 2}O islands can be promoted by alloying more Pt in the Cu-Pt alloys. Increasing the oxidation temperature above 700 °C results in the growth of large Cu{sub 2}O islands that transits to a dendritic growth morphology. The ex situ AFM studies reveal that the nucleation of oxide islands can occur on surface terraces and the subsequent oxide growth depletes local terrace Cu atoms that results in the formation of surface pits.

  1. Modeling Cu Migration in CdTe Solar Cells Under Device-Processing and Long-Term Stability Conditions: Preprint

    SciTech Connect (OSTI)

    Teeter, G.; Asher, S.

    2008-05-01

    An impurity migration model for systems with material interfaces is applied to Cu migration in CdTe solar cells. In the model, diffusion fluxes are calculated from the Cu chemical potential gradient. Inputs to the model include Cu diffusivities, solubilities, and segregation enthalpies in CdTe, CdS and contact materials. The model yields transient and equilibrium Cu distributions in CdTe devices during device processing and under field-deployed conditions. Preliminary results for Cu migration in CdTe photovoltaic devices using available diffusivity and solubility data from the literature show that Cu segregates in the CdS, a phenomenon that is commonly observed in devices after back-contact processing and/or stress conditions.

  2. Preparation and structure characterization of SmCo{sub 5}(0001) epitaxial thin films grown on Cu(111) underlayers

    SciTech Connect (OSTI)

    Ohtake, Mitsuru; Nukaga, Yuri; Futamoto, Masaaki; Kirino, Fumiyoshi

    2009-04-01

    SmCo{sub 5}(0001) epitaxial films were prepared on Cu(111) single-crystal underlayers formed on Al{sub 2}O{sub 3}(0001) substrates at 500 deg. C. The nucleation and growth mechanism of (0001)-oriented SmCo{sub 5} crystal on Cu(111) underlayer is investigated and a method to control the nucleation is proposed. The SmCo{sub 5} epitaxial thin film formed directly on Cu underlayer consists of two types of domains whose orientations are rotated around the film normal by 30 deg. each other. By introducing a thin Co seed layer on the Cu underlayer, a SmCo{sub 5}(0001) single-crystal thin film is successfully obtained. Nucleation of SmCo{sub 5} crystal on Cu underlayer seems controllable by varying the interaction between the Cu underlayer and the SmCo{sub 5} layer.

  3. Oxidative stress, mitochondrial permeability transition, and cell death in Cu-exposed trout hepatocytes

    SciTech Connect (OSTI)

    Krumschnabel, Gerhard . E-mail: Gerhard.Krumschnabel@uibk.ac.at; Manzl, Claudia; Berger, Christian; Hofer, Bettina

    2005-11-15

    We have previously shown that, in trout hepatocytes, exposure to a high dose of copper (Cu) leads to disruption of Ca{sup 2+} homeostasis and elevated formation of reactive oxygen species (ROS), with the latter ultimately causing cell death. In the present study, we aimed at identifying, using a lower Cu concentration, the role of mitochondria in this scenario, the potential involvement of the mitochondrial permeability transition (MPT), and the mode of cell death induced by the metal. Incubation with 10 {mu}M Cu resulted in a strong stimulation of ROS formation, and after 2 h of exposure a significant increase of both apoptotic and necrotic cells was seen. Co-incubation of Cu-treated hepatocytes with the iron-chelator deferoxamine significantly inhibited ROS production and completely prevented cell death. The origin of the radicals generated was at least partly mitochondrial, as visualized by confocal laser scanning microscopy. Furthermore, ROS production was diminished by inhibition of mitochondrial respiration, but since this also aggravated the elevation of intracellular Ca{sup 2+} induced by Cu, it did not preserve cell viability. In a sub-population of cells, Cu induced a decrease of mitochondrial membrane potential and occurrence of the MPT. Cyclosporin A, which did not inhibit ROS formation, prevented the onset of the MPT and inhibited apoptotic, but not necrotic, cell death. Cu-induced apoptosis therefore appears to be dependent on induction of the MPT, but the prominent contribution of mitochondria to ROS generation also suggests an important role of mitochondria in necrotic cell death.

  4. In situ X-ray absorption spectroscopic investigation of the electrochemical conversion reactions of CuF{sub 2}-MoO{sub 3} nanocomposite

    SciTech Connect (OSTI)

    Mansour, A.N.; Badway, F.; Yoon, W.-S.; Chung, K.Y.; Amatucci, G.G.

    2010-12-15

    We have used X-ray absorption spectroscopy at the Cu K-edge to investigate the electrochemical conversion reaction of 20 nm size 85 wt% CuF{sub 2}-15 wt% MoO{sub 3} nanocomposite under in situ conditions. The nanocomposite was prepared by high energy milling. Upon discharge, the lithiation reaction with the nanocomposite resulted in the formation of nanophase metallic Cu, which is consistent with the conversion of CuF{sub 2} into Cu and LiF. Based on XANES and Fourier transforms of EXAFS spectra, we show that the discharge process proceeded via the formation of highly dispersed Cu particles. Based on the coordination number of the first shell of Cu, the average size of the Cu particles was estimated to be in the 1-3 nm range in the fully discharged state. -- Graphical Abstract: Comparison of Fourier transform of in situ Cu K-edge EXAFS spectra for a fully discharged CuF{sub 2{center_dot}}MoO{sub 3} nanocomposite in a nonaqueous Li cell with that of a Cu foil. Quantitative analysis of the Fourier transforms confirmed that the discharge mechanism for the nanocomposite proceeds via the reaction CuF{sub 2}+2Li{yields}Cu+2LiF. The discharge product of Cu is in the form of highly dispersed nanoparticles. Display Omitted

  5. Highly-enhanced reflow characteristics of sputter deposited Cu alloy thin films for large scale integrated interconnections

    SciTech Connect (OSTI)

    Onishi, Takashi; Mizuno, Masao; Yoshikawa, Tetsuya; Munemasa, Jun; Mizuno, Masataka; Kihara, Teruo; Araki, Hideki; Shirai, Yasuharu

    2011-08-01

    An attempt to improve the reflow characteristics of sputtered Cu films was made by alloying the Cu with various elements. We selected Y, Sb, Nd, Sm, Gd, Dy, In, Sn, Mg, and P for the alloys, and ''the elasto-plastic deformation behavior at high temperature'' and ''the filling level of Cu into via holes'' were estimated for Cu films containing each of these elements. From the results, it was found that adding a small amount of Sb or Dy to the sputtered Cu was remarkably effective in improve the reflow characteristics. The microstructure and imperfections in the Cu films before and after high-temperature high-pressure annealing were investigated by secondary ion micrographs and positron annihilation spectroscopy. The results imply that the embedding or deformation mechanism is different for the Cu-Sb alloy films compared to the Cu-Dy alloy films. We consider that the former is embedded by softening or deformation of the Cu matrix, which has a polycrystalline structure, and the latter is embedded by grain boundary sliding.

  6. Effects of competing magnetic interactions on the electronic transport properties of CuCrSe{sub 2}

    SciTech Connect (OSTI)

    Tewari, Girish C.; Jawaharlal Nehru University, New Delhi 110067 ; Karppinen, Maarit; Rastogi, Ashok K.

    2013-02-15

    We have synthesized single-phase samples of the CuCrSe{sub 2} phase that exhibits hexagonal-rhombohedral layered crystal structure with space group R3m. Here we present a detailed study of electronic transport and magnetic properties of CuCrSe{sub 2}. We moreover investigate the heat capacity of CuCrSe{sub 2} in comparison to that of CuCrS{sub 2}. The electrical resistivity of CuCrSe{sub 2} shows metallic-like behavior down to 2 K, while the thermoelectric power is large around 100 {mu}V K{sup -1} at 300 K. A weak anomaly in resistivity and a rounded maximum in magnetic susceptibility are observed around 55 K. No sharp transition at 55 K is observed in the heat capacity of CuCrSe{sub 2}, rather a visible maximum is seen. At low temperatures from 2 to 14 K, the magnetic heat capacity follows T{sup 2}-dependence. We tentatively believe this behavior of CuCrSe{sub 2} to be due to competing magnetic interactions between intralayer Cr atoms. The ferromagnetic Cr-Se-Cr indirect exchange among intralayer Cr atoms is enhanced in the selenide compound (that is more metallic than the sulfide compound), and competes with the antiferromagnetic Cr-Cr direct interactions. The interlayer antiferromagnetic exchange through Cu atoms leads to magnetic ordering at low temperature at T{sub N}=55 K. - Graphical abstract: Comparison of magnetic properties of CuCrSe{sub 2} and CuCrS{sub 2} indicates a sharp cusp-like anomaly in magnetic susceptibility at the antiferromagnetic transition of CuCrS{sub 2} while the maximum of CuCrSe{sub 2} is well rounded. Magnetization is reversible after field-cooling (FC) and zero-field-cooling (ZFC) for both compounds. Highlights: Black-Right-Pointing-Pointer Layered CuCrSe{sub 2} can be synthesized in both fully and partially cation-ordered forms. Black-Right-Pointing-Pointer Contrary to previously believed insulating nature the cation-ordered phase is metallic. Black-Right-Pointing-Pointer Magnetic property of CuCrSe{sub 2} is somewhat different from that of CuCrS{sub 2}. Black-Right-Pointing-Pointer Magnetization and heat capacity data suggest complex short-range ordering for CuCrSe{sub 2}.

  7. Morphology, electrical, and optical properties of heavily doped ZnTe:Cu thin films

    SciTech Connect (OSTI)

    El Akkad, Fikry; Abdulraheem, Yaser

    2013-11-14

    We report on a study of the physical properties of ZnTe:Cu films with Cu content up to ∼12 at. % prepared using rf magnetron sputtering. The composition and lateral homogeneities are studied using X-ray photoelectron spectroscopy (XPS). Atomic force microscopy measurements on films deposited at different substrate temperatures (up to 325 °C) yielded activation energy of 12 kJ/mole for the grains growth. The results of XPS and electrical and optical measurements provide evidence for the formation of the ternary zinc copper telluride alloy in films containing Cu concentration above ∼4 at. %. The XPS results suggest that copper is incorporated in the alloy with oxidation state Cu{sup 1+} so that the alloy formula can be written Zn{sub 1−y}Cu{sub y} Te with y = 2−x, where x is a parameter measuring the stoichiometry in the Cu site. The formation of this alloy causes appreciable shift in the binding energies of the XPS peaks besides an IR shift in the energy band gap. Detailed analysis of the optical absorption data revealed the presence of two additional transitions, besides the band gap one, originating from the Γ{sub 8} and Γ{sub 7} (spin-orbit) valence bands to a donor level at ∼0.34 eV below the Γ{sub 6} conduction band. This interpretation yields a value for the valence band splitting energy Δ≅ 0.87 eV independent of copper concentration. On the other hand, the mechanism of formation of the alloy is tentatively explained in terms of a point defect reaction in which substitutional Cu defect Cu{sub Zn} is also created. Assuming that substitutional Cu is the dominant acceptor in the Zn rich alloy as in ZnTe, its formation energy was determined to be 1.7 eV close to the theoretical value (1.41 eV) in ZnTe.

  8. Significant enhancement of the strength-to-resistivity ratio by using nanotwins in epitaxial Cu films

    SciTech Connect (OSTI)

    Misra, Amit; Ronningh, Filip; Anderoglu, Osman; Zhang, X

    2008-01-01

    Epitaxial nanotwinned Cu films, with an average twin spacing ranging from 7 to 16 nm, exhibit a high ratio of strength-to-electrical resisitivity, -400 MPa({mu}{Omega}cm){sup -1}. The hardness of these Cu films approaches 2.8 GPa, and their electrical resistivities are comparable to that of oxygen-free high-conductivity Cu. Compared to high-angle grain boundaries, coherent twin interfaces possess inherently high resistance to the transmission of single dislocations, and yet an order of magnitude lower electron scattering coefficient, determined to be 1.5-5 x 10{sup -7} {mu}{Omega}cm{sup 2} at room temperature. Analytical studies as well as experimental results show that, in polycrystalline Cu, grain refinement leads to a maximum of the strength-to-resistivity ratio, -250 MPa({mu}{Omega}cm){sup -1}, when grain size is comparable to the mean-free path of electrons. However, in twinned Cu, such a ratio increases continuously with decreasing twin spacing down to a few nanometers. Hence nanoscale growth twins are more effective to achieve a higher strength-to-resistivity ratio than high-angle grain boundaries.

  9. Enhanced irreversibility by crystal defects in the Bi-Sr-Ca-Cu-O system

    SciTech Connect (OSTI)

    Salem-Sugui, S. Jr.; Shi, Donglu; McFarland, S.E.

    1991-04-01

    We measured magnetic irreversibility, H*(T), in liquid-quenched Bi-Sr-Ca-Cu-O samples with various microstructures at high applied field (up to 7 T). We found that H*(T) is considerably increased in the Bi{sub 2}Sr{sub 2}Ca{sub 3}Cu{sub 4}O{sub x} (2234) sample with a large amount of crystal defects, including severe lattice distortion and calcium and copper rich precipitates. We argue that the lattice distortion may affect the degree of anisotropy and the Josephson coupling between the Cu-O layers, which in turn enhance the irreversibility in the Bi-Sr-Ca-Cu-O system. A critical current density, J{sub c}, of 8 {times} 10{sup 4} A/cm{sup 2} at 8 kG and 40 K was obtained in the 2234 sample with many defects, while the J{sub c} dropped significantly at the same temperature and field in the near stoichiometry Bi{sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub x} (2223) sample with a uniform microstructure.

  10. Density functional study of CaN mono and bilayer on Cu(001)

    SciTech Connect (OSTI)

    Zahedifar, Maedeh; Hashemifar, S. Javad, E-mail: hashemifar@cc.iut.ac.ir; Akbarzadeh, Hadi [Department of Physics, Isfahan University of Technology, Isfahan, 84156-83111 (Iran, Islamic Republic of)] [Department of Physics, Isfahan University of Technology, Isfahan, 84156-83111 (Iran, Islamic Republic of)

    2014-01-15

    Density functional - pseudopotential calculations are performed to provide first-principles insights into magnetic behaviour of bulk CaN and CaN monolayers on Cu(001) in the rock-salt (RS) and zinc-blende (ZB) structures. Our results indicate that both RS- and ZB-CaN exhibit half-metallic ferromagnetism originated from the incomplete 2p shell of the nitrogen ion. In contrast to the bulk CaN, the CaN monolayers on Cu(001) generally favor ZB structure. We argue that the more stable ZB-CaN thin films on Cu(001) are nonmagnetic, because of strong Cu-N bonding at the interface, while the less stable Ca terminated ZB-CaN thin films exhibit half-metallic ferromagnetism. The transition path between the high energy ferromagnetic and the stable nonmagnetic configurations of the ZB-CaN monolayer on Cu(001) are studied by using the nudged elastic band method. We observe a two stages transition and an activation barrier of about 1.18 eV in the minimum energy path of this transition.

  11. Kondo-lattice formation in cubic-phase YbCu{sub 5}

    SciTech Connect (OSTI)

    Tsujii, N.; He, J.; Amita, F.; Yoshimura, K.; Kosuge, K.; Michor, H.; Hilscher, G.; Goto, T.

    1997-10-01

    The YbCu{sub 5} phase with C15b structure has been prepared by a high-pressure technique, and its physical properties have been investigated. The temperature dependence of magnetic susceptibility, electrical resistivity, and specific heat show Kondo-lattice formation. Furthermore, a heavy Fermi-liquid state without magnetic ordering down to 2.0 K is found to evolve below about 6 K. The electronic specific heat coefficient {gamma} is enhanced to values as large as to 550 mJ/molthinspK{sup 2}. The magnetization measured up to 40 T at 1.6 K has a field dependence which is expected for a Kondo system when the total angular momentum is J{gt}1. All results are in good agreement with the extrapolation of the previous results of YbCu{sub 5{minus}x}Ag{sub x} (0.125{le}x{le}1.0) for x{r_arrow}0. The concentration dependence of characteristic temperatures of YbCu{sub 5{minus}x}Ag{sub x} can be quantitatively explained by the chemical pressure effect within the compressible Kondo model for the full range of Ag concentration ( 0.0{le}x{le}1.0). The origins of Kondo-lattice formation in YbCu{sub 4}Ag and the valence transition in YbCu{sub 4}In are discussed. {copyright} {ital 1997} {ital The American Physical Society}

  12. Influence of lattice orientation on growth and structure of graphene on Cu(001)

    SciTech Connect (OSTI)

    Wofford, Joseph M.; Nie, Shu; Thrmer, Konrad; McCarty, Kevin F.; Dubon, Oscar D.

    2015-03-31

    We have used low-energy electron microscopy (LEEM) and diffraction (LEED) to examine the significance of lattice orientation in graphene growth on Cu(0 0 1). Individual graphene domains undergo anisotropic growth on the Cu surface, and develop into lens shapes with their long axes roughly aligned with Cu <1 0 0> in-plane directions. Furthermore, the long axis of a lens-shaped domain is only rarely oriented along a C <1 1> direction, suggesting that carbon attachment at zigzag graphene island edges is unfavorable. A kink-mediated adatom attachment process is consistent with the behavior observed here and reported in the literature. Likewise, the details of the ridged moir pattern formed by the superposition of the graphene lattice on the (0 0 1) Cu surface also evolve with the graphene lattice orientation, and are predicted well by a simple geometric model. Managing the kink-mediated growth mode of graphene on Cu(0 0 1) will be necessary for the continued improvement of this graphene synthesis technique.

  13. Theoretical calculation of the melting curve of Cu-Zr binary alloys

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Gunawardana, K. G.S.H.; Wilson, S. R.; Mendelev, M. I.; Song, Xueyu

    2014-11-14

    Helmholtz free energies of the dominant binary crystalline solids found in the Cu-Zr system at high temperatures close to the melting curve are calculated. This theoretical approach combines fundamental measure density functional theory (applied to the hard-sphere reference system) and a perturbative approach to include the attractive interactions. The studied crystalline solids are Cu(fcc), Cu51Zr14(β), CuZr(B2), CuZr2(C11b), Zr(hcp), and Zr(bcc). The calculated Helmholtz free energies of crystalline solids are in good agreement with results from molecular-dynamics (MD) simulations. Using the same perturbation approach, the liquid phase free energies are calculated as a function of composition and temperature, from which themore » melting curve of the entire composition range of this system can be obtained. Phase diagrams are determined in this way for two leading embedded atom method potentials, and the results are compared with experimental data. Furthermore, theoretical melting temperatures are compared both with experimental values and with values obtained directly from MD simulations at several compositions.« less

  14. Theoretical calculation of the melting curve of Cu-Zr binary alloys

    SciTech Connect (OSTI)

    Gunawardana, K. G.S.H.; Wilson, S. R.; Mendelev, M. I.; Song, Xueyu

    2014-11-14

    Helmholtz free energies of the dominant binary crystalline solids found in the Cu-Zr system at high temperatures close to the melting curve are calculated. This theoretical approach combines fundamental measure density functional theory (applied to the hard-sphere reference system) and a perturbative approach to include the attractive interactions. The studied crystalline solids are Cu(fcc), Cu51Zr14(β), CuZr(B2), CuZr2(C11b), Zr(hcp), and Zr(bcc). The calculated Helmholtz free energies of crystalline solids are in good agreement with results from molecular-dynamics (MD) simulations. Using the same perturbation approach, the liquid phase free energies are calculated as a function of composition and temperature, from which the melting curve of the entire composition range of this system can be obtained. Phase diagrams are determined in this way for two leading embedded atom method potentials, and the results are compared with experimental data. Furthermore, theoretical melting temperatures are compared both with experimental values and with values obtained directly from MD simulations at several compositions.

  15. Exponentially decaying magnetic coupling in sputtered thin film FeNi/Cu/FeCo trilayers

    SciTech Connect (OSTI)

    Wei, Yajun Akansel, Serkan; Thersleff, Thomas; Brucas, Rimantas; Lansaker, Pia; Leifer, Klaus; Svedlindh, Peter; Harward, Ian; Celinski, Zbigniew; Ranjbar, Mojtaba; Dumas, Randy K.; Jana, Somnath; Pogoryelov, Yevgen; Karis, Olof; Åkerman, Johan

    2015-01-26

    Magnetic coupling in trilayer films of FeNi/Cu/FeCo deposited on Si/SiO{sub 2} substrates have been studied. While the thicknesses of the FeNi and FeCo layers were kept constant at 100 Å, the thickness of the Cu spacer was varied from 5 to 50 Å. Both hysteresis loop and ferromagnetic resonance results indicate that all films are ferromagnetically coupled. Micromagnetic simulations well reproduce the ferromagnetic resonance mode positions measured by experiments, enabling the extraction of the coupling constants. Films with a thin Cu spacer are found to be strongly coupled, with an effective coupling constant of 3 erg/cm{sup 2} for the sample with a 5 Å Cu spacer. The strong coupling strength is qualitatively understood within the framework of a combined effect of Ruderman-Kittel-Kasuya-Yosida and pinhole coupling, which is evidenced by transmission electron microscopy analysis. The magnetic coupling constant surprisingly decreases exponentially with increasing Cu spacer thickness, without showing an oscillatory thickness dependence. This is partially connected to the substantial interfacial roughness that washes away the oscillation. The results have implications on the design of multilayers for spintronic applications.

  16. Structure and Bonding of Tungsten Oxide Clusters on Nanostructured Cu-O Surfaces

    SciTech Connect (OSTI)

    Wagner, Margareta; Surnev, Svetlozar; Ramsey, Michael; Barcaro, Giovanni; Sementa, Luca; Negreiros, Fabio R.; Fortunelli, Alessandro; Dohnalek, Zdenek; Netzer, Falko P.

    2011-12-01

    (WO3)3 gas-phase clusters generated via vacuum sublimation are deposited under UHV and low temperature (5 K) conditions on a Cu(110) 'stripe' phase consisting of alternating Cu-O (2x1) and clean Cu regions. STM imaging shows that the clusters adsorb as intact units on both substrates, and the suggested adsorption geometries are confirmed by density-functional (DF) simulations. On the clean surface the overall distortion is minor and we are able to image the nodal structure of an individual molecular orbital in the STM at low bias, whereas on the Cu-O surface both the clusters and the substrate are significantly distorted, due to the strong oxygen affinity of W atoms. On both surfaces cluster and Cu electronic states are appreciably mixed, and electron charge is donated by the surface to the cluster. The experimentally STS-determined DOS signature of the adsorption complex consists in two peaks across the Fermi energy and is well reproduced by the DF calculations.

  17. Energetics of the formation of CuAg coreshell nanoparticles

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Chandross, Michael

    2014-10-06

    Our work presents molecular dynamics and Monte Carlo simulations aimed at developing an understanding of the formation of coreshell CuAg nanoparticles. The effects of surface and interfacial energies were considered and used to form a phenomenological model that calculates the energy gained upon the formation of a coreshell structure from two previously distinct, non-interacting nanoparticles. In most cases, the coreshell structure was found to be energetically favored. Specifically, the difference in energy as a function of the radii of the individual Cu and Ag particles was examined, with the assumption that a coreshell structure forms. In general, it was foundmorethat the energetic gain from forming such a structure increased with increasing size of the initial Ag particle. This result was interpreted as a result of the reduction in surface energy. Moreover, for two separate particles, both Cu and Ag contribute to the surface energy; however, for a coreshell structure, the only contribution to the surface energy is from the Ag shell and the Cu contribution is changed to a CuAg interfacial energy, which is always smaller.less

  18. Impact of sulfation and desulfation on NOx reduction using Cu-chabazite SCR catalysts

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Brookshear, Daniel William; Nam, Jeong -Gil; Nguyen, Ke; Toops, Todd J.; Binder, Andrew J.

    2015-06-05

    This bench reactor study investigates the impact of gaseous sulfur on the NOx reduction activity of Cu-chabazite SCR (Cu-CHA) catalysts at SO2 concentrations representative of marine diesel engine exhaust. After two hours of 500 ppm SO2 exposure at 250 and 400 °C in the simulated diesel exhaust gases, the NOx reduction activity of the sulfated Cu-CHA SCR catalysts is severely degraded at evaluation temperatures below 250 °C; however, above 250 °C the impact of sulfur exposure is minimal. EPMA shows that sulfur is located throughout the washcoat and along the entire length of the sulfated samples. Interestingly, BET measurements revealmore » that the sulfated samples have a 20% decrease in surface area. Moreover, the sulfated samples show a decrease in NOx/nitrate absorption during NO exposure in a DRIFTS reactor which suggests that Cu sites in the catalyst are blocked by the presence of sulfur. SO2 exposure also results in an increase in NH3 storage capacity, possibly due to the formation of ammonium sulfate species in the sulfated samples. In all cases, lean thermal treatments as low as 500 °C reverse the effects of sulfur exposure and restore the NOx reduction activity of the Cu-CHA catalyst to that of the fresh condition.« less

  19. Influence of lattice orientation on growth and structure of graphene on Cu(001)

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Wofford, Joseph M.; Nie, Shu; Thürmer, Konrad; McCarty, Kevin F.; Dubon, Oscar D.

    2015-03-31

    We have used low-energy electron microscopy (LEEM) and diffraction (LEED) to examine the significance of lattice orientation in graphene growth on Cu(0 0 1). Individual graphene domains undergo anisotropic growth on the Cu surface, and develop into lens shapes with their long axes roughly aligned with Cu <1 0 0> in-plane directions. Furthermore, the long axis of a lens-shaped domain is only rarely oriented along a C <1 1> direction, suggesting that carbon attachment at “zigzag” graphene island edges is unfavorable. A kink-mediated adatom attachment process is consistent with the behavior observed here and reported in the literature. Likewise, themore » details of the ridged moiré pattern formed by the superposition of the graphene lattice on the (0 0 1) Cu surface also evolve with the graphene lattice orientation, and are predicted well by a simple geometric model. Managing the kink-mediated growth mode of graphene on Cu(0 0 1) will be necessary for the continued improvement of this graphene synthesis technique.« less

  20. A reactive magnetron sputtering route for attaining a controlled core-rim phase partitioning in Cu{sub 2}O/CuO thin films with resistive switching potential

    SciTech Connect (OSTI)

    Ogwu, A. A.; Darma, T. H.

    2013-05-14

    The achievement of a reproducible and controlled deposition of partitioned Cu{sub 2}O/CuO thin films by techniques compatible with ULSI processing like reactive magnetron sputtering has been reported as an outstanding challenge in the literature. This phase partitioning underlies their performance as reversible resistive memory switching devices in advanced microelectronic applications of the future. They are currently fabricated by thermal oxidation and chemical methods. We have used a combination of an understanding from plasma chemistry, thermo-kinetics of ions, and rf power variation during deposition to successfully identify a processing window for preparing partitioned Cu{sub 2}O/CuO films. The production of a core rich Cu{sub 2}O and surface rich Cu{sub 2}O/CuO mixture necessary for oxygen migration during resistive switching is confirmed by XRD peaks, Fourier transform infra red Cu (I)-O vibrational modes, XPS Cu 2P{sub 3/2} and O 1S peak fitting, and a comparison of satellite peak ratio's in Cu 2P{sub 3/2} fitted peaks. We are proposing based on the findings reported in this paper that an XPS satellite peak intensity(I{sub s}) to main peak intensity ratio (I{sub m}) {<=} 0.45 as an indicator of a core rich Cu{sub 2}O and surface rich Cu{sub 2}O/CuO formation in our prepared films. CuO is solely responsible for the satellite peaks. This is explained on the basis that plasma dissociation of oxygen will be limited to the predominant formation of Cu{sub 2}O under certain plasma deposition conditions we have identified in this paper, which also results in a core-rim phase partitioning. The deposited films also followed a Volmer-Weber columnar growth mode, which could facilitate oxygen vacancy migration and conductive filaments at the columnar interfaces. This is further confirmed by optical transmittance and band-gap measurements using spectrophotometry. This development is expected to impact on the early adoption of copper oxide based resistive memory electronic switching devices in advanced electronic devices of the future. The relative abundance of copper is another major complementary driver for the interest in copper oxide films.

  1. Effect of cooling rate on the microstructure and microhardness of the CuZrAgAl alloy

    SciTech Connect (OSTI)

    Liu, Y.; Blandin, J.J.; Suery, M.; Kapelski, G.

    2012-08-15

    The effect of cooling rate on the microstructure and microhardness of the Cu{sub 40}Zr{sub 44}Ag{sub 8}Al{sub 8} (at.%) alloy has been studied. The crystalline phases were characterized by X-ray diffraction, optical microscopy and scanning electron microscopy with energy dispersive X-ray spectroscopy, and identified as AlCu{sub 2}Zr, Cu{sub 10}Zr{sub 7} and CuZr{sub 2}. The solidification sequence was established as following: the Cu{sub 10}Zr{sub 7} phase forms first in the periphery of the rod, then following with AlCu{sub 2}Zr phase in the rod center and finally CuZr{sub 2} crystals in Cu-depleted areas. The effect of crystals on the mechanical properties of the Cu{sub 40}Zr{sub 44}Ag{sub 8}Al{sub 8} alloy was also estimated through the microhardness. According to the value of microhardness, inhomogeneous structure of the amorphous matrix is more easily formed for the alloy in the low cooling rate (i.e., 9 mm) as compared with the alloy with fully amorphous state in the large cooling rate (i.e., 3 mm). This inhomogeneous structure was attributed to the composition change of amorphous matrix arising from the forming of crystalline phases due to the low cooling rate. - Highlights: Black-Right-Pointing-Pointer The crystalline phases in the Cu{sub 40}Zr{sub 44}Ag{sub 8}Al{sub 8} alloy were identified. Black-Right-Pointing-Pointer The solidification sequence of Cu{sub 40}Zr{sub 44}Ag{sub 8}Al{sub 8} alloy was verified. Black-Right-Pointing-Pointer The softening and hardening of alloy could be observed due to the crystallization.

  2. Structural and magnetic phase transitions in CeCu6-xTx (T = Ag,Pd)

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Poudel, Lekhanath N.; De la cruz, Clarina; Payzant, E. Andrew; Koehler, Michael R.; May, Andrew F.; Garlea, Vasile O.; Taylor, Alice E.; Parker, David S.; Cao, Huibo B.; McGuire, Michael A.; et al

    2015-12-15

    The structural and the magnetic properties of CeCu6-xAgx (0 ≤ x ≤ 0.85) and CeCu6-xPdx (0 ≤ x ≤ 0.4) have been studied using neutron diffraction, resonant ultrasound spectroscopy (RUS), x-ray diffraction measurements, and first principles calculations. The structural and magnetic phase diagrams of CeCu6-xAgx and CeCu6-xPdx as a function of Ag/Pd composition are reported. The end member, CeCu6, undergoes a structural phase transition from an orthorhombic (Pnma) to a monoclinic (P21/c) phase at 240 K. In CeCu6-xAgx, the structural phase transition temperature (Ts) decreases linearly with Ag concentration and extrapolates to zero at xS ≈ 0.1. The structural transitionmore » in CeCu6-xPdx remains unperturbed with Pd substitution within the range of our study. The lattice constant b slightly decreases with Ag/Pd doping, whereas a and c increase with an overall increase in the unit cell volume. Both systems, CeCu6-xAgx and CeCu6-xPdx, exhibit a magnetic quantum critical point (QCP), at x ≈ 0.2 and x ≈ 0.05, respectively. Near the QCP, long range antiferromagnetic ordering takes place at an incommensurate wave vector (δ1 0 δ2), where δ1 ~ 0.62, δ2 ~ 0.25, x = 0.125 for CeCu6-xPdx and δ1 ~ 0.64, δ2 ~ 0.3, x = 0.3 for CeCu6-xAgx. As a result, the magnetic structure consists of an amplitude modulation of the Ce moments which are aligned along the c axis of the orthorhombic unit cell.« less

  3. Enhanced spin Hall effect by electron correlations in CuBi alloys

    SciTech Connect (OSTI)

    Gu, Bo Xu, Zhuo; Mori, Michiyasu; Maekawa, Sadamichi; Ziman, Timothy

    2015-05-07

    A recent experiment in CuBi alloys obtained a large spin Hall angle (SHA) of ?0.24 (Niimi et al., Phys. Rev. Lett. 109, 156602 (2012)). We find that the SHA can be dramatically enhanced by Bi impurities close to the Cu surface. The mechanisms of this enhancement are two-fold. One is that the localized impurity state on surface has a decreased hybridization and combined with Coulomb correlation effect. The other comes from the low-dimensional state of conduction electrons on surface, which results in a further enhancement of skew scattering by impurities. Furthermore, we note that a discrepancy in sign of SHA between the experiment and previous theories is simply caused by different definitions of SHA. This re-establishes skew scattering as the essential mechanism underlying the spin Hall effect in CuBi alloys.

  4. Low-cost CuInSe[sub 2] submodule development

    SciTech Connect (OSTI)

    Basol, B.M.; Kapur, V.K.; Halani, A.; Leidholm, C. )

    1992-10-01

    Aim of this project is development and demonstration of processing steps necessary for fabrication of high efficiency CuInSe[sub 2] solar cells and sub-modules by the two-stage technique (also called the selenization method.) During this period, we have optimized the processing parameters of this method and demonstrated CuInSe[sub 2]/CdS/ZnO devices with a 1[endash]4 cm[sup 2] area and up to 12.4% active area efficiency. We have also developed a novel approach for the preparation of Cu/In precursors that improved the stoichiometric and morphological uniformity in these films. We have developed processing steps and tooling for handling up to 1 ft[sup 2] size substrates and as a result of these efforts demonstrated our first monolithically integrated sub-module of 1 ft[sup 2] area. 16 figs, 1 tab, 15 refs.

  5. Stable n-CuInSe/sub 2/iodide-iodine photoelectrochemical cell

    DOE Patents [OSTI]

    Cahen, D.; Chen, Y.W.

    1984-09-20

    In a photoelectrochemical solar cell, stable output and solar efficiency in excess of 10% are achieved with a photoanode of n-CuInSe/sub 2/ electrode material and an iodine/iodide redox couple used in a liquid electrolyte. The photoanode is prepared by treating the electrode material by chemical etching, for example in Br/sub 2//MeOH; heating the etched electrode material in air or oxygen; depositing a surface film coating of indium on the electrode material after the initial heating; and thereafter again heating the electrode material in air or oxygen to oxidize the indium. The electrolyte is treated by the addition of Cu/sup +/ or Cu/sup 2 +/ salts and in In/sup 3 +/ salts.

  6. Stable N-CuInSe.sub.2 /iodide-iodine photoelectrochemical cell

    DOE Patents [OSTI]

    Cahen, David; Chen, Yih W.

    1985-01-01

    In a photoelectrochemical solar cell, stable output and solar efficiency in excess of 10% are achieved with a photoanode of n-CuInSe.sub.2 electrode material and an iodine/iodide redox couple used in a liquid electrolyte. The photoanode is prepared by treating the electrode material by chemical etching, for example in Br.sub.2 /MeOH; heating the etched electrode material in air or oxygen; depositing a surface film coating of indium on the electrode material after the initial heating; and thereafter again heating the electrode material in air or oxygen to oxidize the indium. The electrolyte is treated by the addition of Cu.sup.+ or Cu.sup.2+ salts and In.sup.3+ salts.

  7. Effects of Cr/Zn Substitutions on Dielectric Properties of CaCu{sub

    Office of Scientific and Technical Information (OSTI)

    3}Ti{sub 4}O{sub 12}(CCTO) Ceramics (Journal Article) | SciTech Connect Effects of Cr/Zn Substitutions on Dielectric Properties of CaCu{sub 3}Ti{sub 4}O{sub 12}(CCTO) Ceramics Citation Details In-Document Search Title: Effects of Cr/Zn Substitutions on Dielectric Properties of CaCu{sub 3}Ti{sub 4}O{sub 12}(CCTO) Ceramics Effects of Zn and Cr substitutions on dielectric properties of CaCu{sub 3-x}Zn{sub x}Ti{sub 4-y}Cr{sub y}O{sub 12} ceramics are reported. Dielectric measurements at room

  8. Role of polycrystallinity in CdTe and CuInSe sub 2 photovoltaic cells

    SciTech Connect (OSTI)

    Sites, J.R. )

    1991-01-01

    The polycrystalline nature of thin-film CdTe and CuInSe{sub 2} solar cells continues to be a major factor in several individual losses that limit overall cell efficiency. This report describes progress in the quantitative separation of these losses, including both measurement and analysis procedures. It also applies these techniques to several individual cells to help document the overall progress with CdTe and CuInSe{sub 2} cells. Notably, CdTe cells from Photon Energy have reduced window photocurrent losses to 1 mA/Cm{sup 2}; those from the University of South Florida have achieved a maximum power voltage of 693 mV; and CuInSe{sub 2} cells from International Solar Electric Technology have shown a hole density as high as 7 {times} 10{sup 16} cm{sup {minus}3}, implying a significant reduction in compensation. 9 refs.

  9. Interpretation of thermoelectric properties of Cu substituted LaCoO{sub 3} ceramics

    SciTech Connect (OSTI)

    Choudhary, K. K.; Kaurav, N.; Sharma, U.; Ghosh, S. K.

    2014-04-24

    The thermoelectric properties of LaCo{sub 1?x}Cu{sub x}O{sub 3??} is theoretically analyzed, it is observed that thermoelectric figure of merit ZT (=S{sup 2}?T/?) is maximized by Cu substitution in LaCoO{sub 3} Ceramics at x=0.15. The lattice thermal conductivity and thermoelectric power were estimated by the scattering of phonons with defects, grain boundaries, electrons and phonons to evaluate the thermoelectric properties. We found that Cu substitution increase the phonon scattering with grain boundaries and defects which significantly increase the thermoelectric power and decrease the thermal conductivity. The present numerical analysis will help in designing more efficient thermoelectric materials.

  10. Optical and quantum efficiency analysis of (Ag,Cu)(In,Ga)Se2 absorber layers

    SciTech Connect (OSTI)

    Boyle, Jonathan; Hanket, Gregory; Shafarman, William

    2009-06-09

    (Ag,Cu)(In,Ga)Se2 thin films have been deposited by elemental co-evaporation over a wide range of compositions and their optical properties characterized by transmission and reflection measurements and by relative shift analysis of quantum efficiency device measurements. The optical bandgaps were determined by performing linear fits of (?h?)2 vs. h?, and the quantum efficiency bandgaps were determined by relative shift analysis of device curves with fixed Ga/(In+Ga) composition, but varying Ag/(Cu+Ag) composition. The determined experimental optical bandgap ranges of the Ga/(In+Ga) = 0.31, 0.52, and 0.82 groups, with Ag/(Cu+Ag) ranging from 0 to 1, were 1.19-1.45 eV, 1.32-1.56 eV, and 1.52-1.76 eV, respectively. The optical bowing parameter of the different Ga/(In+Ga) groups was also determined.

  11. Effect of Cu addition on the martensitic transformation of powder metallurgy processed Ti–Ni alloys

    SciTech Connect (OSTI)

    Kim, Yeon-wook; Choi, Eunsoo

    2014-10-15

    Highlights: • M{sub s} of Ti{sub 50}Ni{sub 50} powders is 22 °C, while M{sub s} of SPS-sintered porous bulk increases up to 50 °C. • M{sub s} of Ti{sub 50}Ni{sub 40}Cu{sub 20} porous bulk is only 2 °C higher than that of the powders. • Recovered stain of porous TiNi and TiNiCu alloy is more than 1.5%. - Abstract: Ti{sub 50}Ni{sub 50} and Ti{sub 50}Ni{sub 30}Cu{sub 20} powders were prepared by gas atomization and their transformation behaviors were examined by means of differential scanning calorimetry and X-ray diffraction. One-step B2–B19’ transformation occurred in Ti{sub 50}Ni{sub 50} powders, while Ti{sub 50}Ni{sub 30}Cu{sub 20} powders showed B2–B19 transformation behavior. Porous bulks with 24% porosity were fabricated by spark plasma sintering. The martensitic transformation start temperature (50 °C) of Ti{sub 50}Ni{sub 50} porous bulk is much higher than that (22 °C) of the as-solidified powders. However, the martensitic transformation start temperature (35 °C) of Ti{sub 50}Ni{sub 30}Cu{sub 20} porous bulk is almost the same as that (33 °C) of the powders. When the specimens were compressed to the strain of 8% and then unloaded, the residual strains of Ti{sub 50}Ni{sub 50} and Ti{sub 50}Ni{sub 30}Cu{sub 20} alloy bulks were 3.95 and 3.7%, respectively. However, these residual strains were recovered up to 1.7% after heating by the shape memory phenomenon.

  12. High-power Laser Interaction With Low-density C-Cu Foams (Journal Article)

    Office of Scientific and Technical Information (OSTI)

    | SciTech Connect High-power Laser Interaction With Low-density C-Cu Foams Citation Details In-Document Search Title: High-power Laser Interaction With Low-density C-Cu Foams Authors: Perez, F ; Colvin, J D ; May, M J ; Charnvanichborikarn, S ; Kucheyev, S O ; Felter, T E ; Fournier, K B Publication Date: 2015-08-24 OSTI Identifier: 1234590 Report Number(s): LLNL-JRNL-677081 Journal ID: ISSN 1070-664X DOE Contract Number: AC52-07NA27344 Resource Type: Journal Article Resource Relation:

  13. Kondo interactions from band reconstruction in YbInCu 4 (Journal Article) |

    Office of Scientific and Technical Information (OSTI)

    SciTech Connect interactions from band reconstruction in YbInCu 4 Citation Details In-Document Search Title: Kondo interactions from band reconstruction in YbInCu 4 We combine resonant inelastic X-ray scattering (RIXS) and model calculations in the Kondo lattice compound YbInCu₄, a system characterized by a dramatic increase in Kondo temperature and associated valence fluctuations below a first-order valence transition at T≃42 K. In this study, the bulk-sensitive, element-specific, and

  14. Magnetization of underdoped YBa 2 Cu 3 O y above the irreversibility field

    Office of Scientific and Technical Information (OSTI)

    (Journal Article) | SciTech Connect Magnetization of underdoped YBa 2 Cu 3 O y above the irreversibility field Citation Details In-Document Search This content will become publicly available on November 22, 2016 Title: Magnetization of underdoped YBa 2 Cu 3 O y above the irreversibility field Authors: Yu, Jing Fei ; Ramshaw, B. J. ; Kokanović, I. ; Modic, K. A. ; Harrison, N. ; Day, James ; Liang, Ruixing ; Hardy, W. N. ; Bonn, D. A. ; McCollam, A. ; Julian, S. R. ; Cooper, J. R.

  15. Measurement of cross sections for the Cu-63(alpha,gamma)Ga-67 reaction from

    Office of Scientific and Technical Information (OSTI)

    5.9-8.7 MeV (Journal Article) | SciTech Connect Measurement of cross sections for the Cu-63(alpha,gamma)Ga-67 reaction from 5.9-8.7 MeV Citation Details In-Document Search Title: Measurement of cross sections for the Cu-63(alpha,gamma)Ga-67 reaction from 5.9-8.7 MeV Authors: Basunia, M S ; Norman, E B ; Shugart, H A ; Smith, A R ; Dolinski, M J ; Quiter, B J Publication Date: 2005-02-24 OSTI Identifier: 15020440 Report Number(s): UCRL-JRNL-210075 DOE Contract Number: W-7405-ENG-48 Resource

  16. Multiscale twin hierarchy in NiMnGa shape memory alloys with Fe and Cu

    Office of Scientific and Technical Information (OSTI)

    (Journal Article) | DOE PAGES Multiscale twin hierarchy in NiMnGa shape memory alloys with Fe and Cu This content will become publicly available on April 30, 2017 « Prev Next » Title: Multiscale twin hierarchy in NiMnGa shape memory alloys with Fe and Cu Authors: Barabash, Rozaliya I. ; Barabash, Oleg M. ; Popov, Dmitry ; Shen, Guoyin ; Park, Changyong ; Yang, Wenge Publication Date: 2015-04-01 OSTI Identifier: 1250957 Grant/Contract Number: FG02-99ER45775; NA0001974 Type: Publisher's

  17. Molecular dynamics simulations of organic SIMS with Cu{sub n} (n=1-3) clusters

    SciTech Connect (OSTI)

    Townes, J. A.; White, A. K.; Krantzman, K. D.; Garrison, B. J.

    1999-06-10

    Molecular dynamics simulations have been performed to study the effect of cluster size on the emission yield and damage cross section in organic SIMS. A model system composed of a monolayer of biphenyl molecules on a Cu(001) substrate was bombarded with Cu{sub n} (n=1-3) projectiles at kinetic energies of 0.100 keV per atom. The yield increases with cluster size, but a nonlinear enhancement in yield is not observed. The yield-to-damage ratio, on the other hand, increases with the use of clusters, indicating that clusters have the potential to improve the sensitivity of SIMS.

  18. Semiconductor bridge, SCB, ignition studies of Al/CuO thermite

    SciTech Connect (OSTI)

    Bickes, R.W. Jr.; Wackerbarth, D.E.; Mohler, J.H.

    1997-04-01

    The authors briefly summarize semiconductor bridge operation and review their ignition studies of Al/CuO thermite as a function of the capacitor discharge unit (CDU) firing set capacitance, charge holder material and morphology of the CuO. Ignition thresholds were obtained using a brass charge holder and a non-conducting fiber-glass-epoxy composite material, G10. At - 18 C and a charge voltage of 50V, the capacitance thresholds were 30.1 {mu}F and 2.0 {mu}F respectively. They also present new data on electrostatic discharge (ESD) and radio frequency (RF) vulnerability tests.

  19. Electronic band structure imaging of three layer twisted graphene on single crystal Cu(111)

    SciTech Connect (OSTI)

    Marquez Velasco, J.; Department of Physics, National Technical University of Athens, Athens ; Kelaidis, N.; Xenogiannopoulou, E.; Tsoutsou, D.; Tsipas, P.; Speliotis, Th.; Pilatos, G.; Likodimos, V.; Falaras, P.; Dimoulas, A.; Raptis, Y. S.

    2013-11-18

    Few layer graphene (FLG) is grown on single crystal Cu(111) by Chemical Vapor Deposition, and the electronic valence band structure is imaged by Angle-Resolved Photo-Emission Spectroscopy. It is found that graphene essentially grows polycrystalline. Three nearly ideal Dirac cones are observed along the Cu ?{sup }K{sup } direction in k-space, attributed to the presence of ?4 twisted three layer graphene with negligible interlayer coupling. The number of layers and the stacking order are compatible with Raman data analysis demonstrating the complementarity of the two techniques for a more accurate characterization of FLG.

  20. Ti3CrCu4: A possible 2-D ferromagnetic spin fluctuating system (Journal

    Office of Scientific and Technical Information (OSTI)

    Article) | SciTech Connect SciTech Connect Search Results Journal Article: Ti3CrCu4: A possible 2-D ferromagnetic spin fluctuating system Citation Details In-Document Search Title: Ti3CrCu4: A possible 2-D ferromagnetic spin fluctuating system Authors: Dhar, S. K. [1] ; Provino, A. [2] ; Manfrinetti, P. [2] ; Kulkarni, R. [1] ; Goyal, Neeraj [1] ; Paudyal, D. [3] + Show Author Affiliations Department of Condensed Matter Physics & Materials Science, T.I.F.R., Homi Bhabha Road, Colaba,

  1. Yb-Zn-Al ternary system: CaCu{sub 5}-type derived compounds in the

    Office of Scientific and Technical Information (OSTI)

    zinc-rich corner (Journal Article) | SciTech Connect Yb-Zn-Al ternary system: CaCu{sub 5}-type derived compounds in the zinc-rich corner Citation Details In-Document Search Title: Yb-Zn-Al ternary system: CaCu{sub 5}-type derived compounds in the zinc-rich corner As part of a study of the Yb-Zn-Al system, this first article reports the synthesis and crystal structure of four compounds. The crystal structures were determined by single crystal diffractometer data for three of them: Yb{sub

  2. Synthesis of highly phase pure (Bi, Pb)-Sr-Ca-Cu-O superconductor

    DOE Patents [OSTI]

    Dorris, Stephen E.; Poeppel, Roger B.; Prorok, Barton C.; Lanagan, Michael T.; Maroni, Victor A.

    1994-01-01

    An article and method of manufacture of (Bi,Pb)-Sr-Ca-Cu-O superconductor. The superconductor is manufactured by preparing a first powdered mixture of bismuth oxide, lead oxide, strontium carbonate, calcium carbonate and copper oxide. A second powdered mixture is then prepared of strontium carbonate, calcium carbonate and copper oxide. The mixtures are calcined separately with the two mixtures then combined. The resulting combined mixture is then subjected to a powder in tube deformation and thermal processing to produce a substantially phase pure (Bi,Pb)-Sr-Ca-Cu-O superconductor.

  3. Synthesis of highly phase pure (Bi, Pb)-Sr-Ca-Cu-O superconductor

    DOE Patents [OSTI]

    Dorris, S.E.; Poeppel, R.B.; Prorok, B.C.; Lanagan, M.T.; Maroni, V.A.

    1994-10-11

    An article and method of manufacture of (Bi,Pb)-Sr-Ca-Cu-O superconductor are disclosed. The superconductor is manufactured by preparing a first powdered mixture of bismuth oxide, lead oxide, strontium carbonate, calcium carbonate and copper oxide. A second powdered mixture is then prepared of strontium carbonate, calcium carbonate and copper oxide. The mixtures are calcined separately with the two mixtures then combined. The resulting combined mixture is then subjected to a powder in tube deformation and thermal processing to produce a substantially phase pure (Bi,Pb)-Sr-Ca-Cu-O superconductor. 5 figs.

  4. Performance and mix measurements of indirect drive Cu doped Be implosions

    Office of Scientific and Technical Information (OSTI)

    (Journal Article) | SciTech Connect Performance and mix measurements of indirect drive Cu doped Be implosions Citation Details In-Document Search Title: Performance and mix measurements of indirect drive Cu doped Be implosions Authors: Casey, D T ; Woods, T ; Smalyuk, V A ; Hurricane, O A ; Glebov, V Y ; Stoeckl, C ; Theobald, W ; Wallace, R ; Nikroo, A ; Shuldberg, C ; Wu, K J ; Frenje, J A ; Perez, F ; Landen, O L ; Remington, B ; Glendinning, G Publication Date: 2014-09-18 OSTI

  5. Competing charge, spin, and superconducting orders in underdoped YBa 2 Cu 3

    Office of Scientific and Technical Information (OSTI)

    O y (Journal Article) | SciTech Connect YBa 2 Cu 3 O y Citation Details In-Document Search Title: Competing charge, spin, and superconducting orders in underdoped YBa 2 Cu 3 O y Authors: Hücker, M. ; Christensen, N. B. ; Holmes, A. T. ; Blackburn, E. ; Forgan, E. M. ; Liang, Ruixing ; Bonn, D. A. ; Hardy, W. N. ; Gutowski, O. ; Zimmermann, M. v. ; Hayden, S. M. ; Chang, J. Publication Date: 2014-08-21 OSTI Identifier: 1180599 Grant/Contract Number: AC02-06CH11357; AC02-98CH10886 Type:

  6. Competing charge, spin, and superconducting orders in underdoped YBa2Cu3Oy

    Office of Scientific and Technical Information (OSTI)

    (Journal Article) | SciTech Connect YBa2Cu3Oy Citation Details In-Document Search Title: Competing charge, spin, and superconducting orders in underdoped YBa2Cu3Oy Authors: Huecker M. ; Christensen, N. B. ; Holmes, A. T. ; Blackburn, E. ; Forgan, E. M. ; Liang, Ruixing ; Bonn, D. A. ; Hardy, W. N. ; Gutowski, O. ; v Zimmermann, M. ; Hayden, S. M. ; Chang, J. Publication Date: 2014-08-01 OSTI Identifier: 1178217 Report Number(s): BNL--106215-2014-JA R&D Project: PO010; KC0201060 DOE

  7. Dielectronic recombination of Zn-like W 44 + from Cu-like W 45 + (Journal

    Office of Scientific and Technical Information (OSTI)

    Article) | SciTech Connect Dielectronic recombination of Zn-like W 44 + from Cu-like W 45 + Citation Details In-Document Search This content will become publicly available on June 23, 2016 Title: Dielectronic recombination of Zn-like W 44 + from Cu-like W 45 + Authors: Safronova, U. I. ; Safronova, A. S. ; Beiersdorfer, P. Publication Date: 2015-06-24 OSTI Identifier: 1188517 Grant/Contract Number: AC52-07NA27344; NA0001984 Type: Publisher's Accepted Manuscript Journal Name: Physical Review

  8. Mechanism of Methanol Synthesis on Cu through CO2 and CO Hydrogenation

    SciTech Connect (OSTI)

    Grabow, Lars C.; Mavrikakis, Manos

    2011-03-04

    We present a comprehensive mean-field microkinetic model for the methanol synthesis and water-gas-shift (WGS) reactions that includes novel reaction intermediates, such as formic acid (HCOOH) and hydroxymethoxy (CH?O?) and allows for the formation of formic acid (HCOOH), formaldehyde (CH?O), and methyl formate (HCOOCH?) as byproducts. All input model parameters were initially derived from periodic, self-consistent, GGA-PW91 density functional theory calculations on the Cu(111) surface and subsequently fitted to published experimentalmethanol synthesis rate data, which were collected under realistic conditions on a commercial Cu/ZnO/Al?O? catalyst. We find that the WGS reaction follows the carboxyl (COOH)-mediated path and that both CO and CO? hydrogenation pathways are active for methanol synthesis. Under typical industrial methanol synthesis conditions, CO? hydrogenation is responsible for ?2/3 of the methanol produced. The intermediates of the CO? pathway for methanol synthesis include HCOO*, HCOOH*, CH?O?*, CH?O*, and CH?O*. The formation of formate (HCOO*) from CO?* and H* on Cu(111) does not involve an intermediate carbonate (CO?*) species, and hydrogenation of HCOO* leads to HCOOH* instead of dioxymethylene (H?CO?*). The effect of CO is not only promotional; CO* is also hydrogenated in significant amounts to HCO*, CH?O *, CH?O*, and CH?OH*. We considered two possibilities for CO promotion: (a) removal of OH* via COOH* to form CO? and hydrogen (WGS), and (b) CO-assisted hydrogenation of various surface intermediates, with HCO* being the H-donor. Only the former mechanism contributes to methanol formation, but its effect is small compared with that of direct CO hydrogenation to methanol. Overall, methanol synthesis rates are limited by methoxy (CH?O*) formation at low CO?/(CO+CO?) ratios and by CH?O* hydrogenation in CO?-rich feeds. CH?O* hydrogenation is the common slow step for both the CO and the CO? methanol synthesis routes; the relative contribution of each route is determined by their respective slow steps HCO*+H*?CH?O*+* and HCOOH*+H*?CH?O?*+* as well as by feed composition and reaction conditions. An analysis of the fitted parameters for a commercial Cu/ZnO/Al?O? catalyst suggests that a more open Cu surface, for example, Cu(110), Cu(100), and Cu(211) partially covered by oxygen, may provide a better model for the active site of methanol synthesis, but our studies cannot exclude a synergistic effect with the ZnO support.

  9. Method of producing superconducting fibers of YBA2CU30X

    DOE Patents [OSTI]

    Schwartzkopf, Louis A.; Ostenson, Jerome E.; Finnemore, Douglas K.

    1990-11-13

    Fibers of YBa.sub.2 Cu.sub.3 O.sub.x have been produce by pendant drop melt extraction. This technique involves the end of a rod of YBa.sub.2 Cu.sub.3 O.sub.x melted with a hydrogen-oxygen torch, followed by lowering onto the edge of a spinning wheel. The fibers are up to 10 cm in length with the usual lateral dimensions, ranging from 20 .mu.m to 125 .mu.m. The fibers require a heat treatment to make them superconducting.

  10. The structure of oxygen on Cu(100) at low and high coverages (Journal

    Office of Scientific and Technical Information (OSTI)

    Article) | SciTech Connect The structure of oxygen on Cu(100) at low and high coverages Citation Details In-Document Search Title: The structure of oxygen on Cu(100) at low and high coverages No abstract prepared. Authors: Kittel, M. ; Polcik, M. ; Terborg, R. ; Hoeft, J.T. ; Baumgartel, P. ; Bradshaw, A.M. ; Toomes, R.L. ; Kang, J.H. ; Woodruff, D.P. ; Pascal, M. ; Lamont, C.L.A. ; Rotenberg, E. Publication Date: 2001-01-01 OSTI Identifier: 903114 Report Number(s): LBNL--48232 Journal ID:

  11. Ti3CrCu4: A possible 2-D ferromagnetic spin fluctuating system (Journal

    Office of Scientific and Technical Information (OSTI)

    Article) | DOE PAGES Ti3CrCu4: A possible 2-D ferromagnetic spin fluctuating system Title: Ti3CrCu4: A possible 2-D ferromagnetic spin fluctuating system Authors: Dhar, S. K. [1] ; Provino, A. [2] ; Manfrinetti, P. [2] ; Kulkarni, R. [1] ; Goyal, Neeraj [1] ; Paudyal, D. [3] + Show Author Affiliations Department of Condensed Matter Physics & Materials Science, T.I.F.R., Homi Bhabha Road, Colaba, Mumbai, 400005, India Department of Chemistry, University of Genova, Via Dodecaneso 31, 16146

  12. Hydrogenation of CO2 to methanol on CeOx/Cu(111) and ZnO/Cu(111) catalysts: Role of the metal-oxide interface and importance of Ce3+ sites

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Sanjaya D. Senanayake; Ramirez, Pedro J.; Waluyo, Iradwikanari; Kundu, Shankhamala; Mudiyanselage, Kumudu; Liu, Zongyuan; Liu, Zhi; Axnanda, Stephanus; Stacchiola, Dario J.; Evans, Jaime; et al

    2016-01-06

    The role of the interface between a metal and oxide (CeOx–Cu and ZnO–Cu) is critical to the production of methanol through the hydrogenation of CO2 (CO2 + 3H2 → CH3OH + H2O). The deposition of nanoparticles of CeOx or ZnO on Cu(111), θoxi < 0.3 monolayer, produces highly active catalysts for methanol synthesis. The catalytic activity of these systems increases in the sequence: Cu(111) < ZnO/Cu(111) < CeOx/Cu(111). The apparent activation energy for the CO2 → CH3OH conversion decreases from 25 kcal/mol on Cu(111) to 16 kcal/mol on ZnO/Cu(111) and 13 kcal/mol on CeOx/Cu(111). The surface chemistry of the highlymore » active CeOx–Cu(111) interface was investigated using ambient pressure X-ray photoemission spectroscopy (AP-XPS) and infrared reflection absorption spectroscopy (AP-IRRAS). Both techniques point to the formation of formates (HCOO–) and carboxylates (CO2δ–) during the reaction. Our results show an active state of the catalyst rich in Ce3+ sites which stabilize a CO2δ– species that is an essential intermediate for the production of methanol. Furthermore, the inverse oxide/metal configuration favors strong metal–oxide interactions and makes possible reaction channels not seen in conventional metal/oxide catalysts.« less

  13. Composition dependence of the in-plane Cu-O bond-stretching LO phonon mode in YBa2Cu3O6+x

    SciTech Connect (OSTI)

    Stercil, F.; Egami, T.; Mook Jr, Herbert A; Yethiraj, Mohana; Chung, J.-H.; Arai, M.; Frost, C.; Dogan, F.

    2008-01-01

    An inelastic pulsed neutron scattering study was performed on the dependence of the dispersion and spectral intensity of the in-plane Cu-O bond-stretching LO phonon mode on doped charge density. The measurements were made in the time-of-flight mode with the multiangle position sensitive spectrometer of the ISIS facility on single crystals of YBa{sub 2}Cu{sub 3}O{sub 6+x} (x=0.15, 0.35, 0.6, 0.7, and 0.95). The focus of the study is the in-plane Cu-O bond-stretching LO phonon mode, which is known for strong electron-phonon coupling and unusual dependence on composition and temperature. It is shown that the dispersions for the samples with x=0.35, 0.6, and 0.7 are similar to the superposition of those for x=0.15 and 0.95 samples, and cannot be explained in terms of the structural anisotropy. It is suggested that the results are consistent with the model of nanoscale electronic phase separation, with the fraction of the phases being dependent on the doped charge density.

  14. ZnO/Cu(InGa)Se.sub.2 solar cells prepared by vapor phase Zn doping

    DOE Patents [OSTI]

    Ramanathan, Kannan; Hasoon, Falah S.; Asher, Sarah E.; Dolan, James; Keane, James C.

    2007-02-20

    A process for making a thin film ZnO/Cu(InGa)Se.sub.2 solar cell without depositing a buffer layer and by Zn doping from a vapor phase, comprising: depositing Cu(InGa)Se.sub.2 layer on a metal back contact deposited on a glass substrate; heating the Cu(InGa)Se.sub.2 layer on the metal back contact on the glass substrate to a temperature range between about 100.degree. C. to about 250.degree. C.; subjecting the heated layer of Cu(InGa)Se.sub.2 to an evaporant species from a Zn compound; and sputter depositing ZnO on the Zn compound evaporant species treated layer of Cu(InGa)Se.sub.2.

  15. Photocatalytic performances and activities of Ag-doped CuFe{sub 2}O{sub 4} nanoparticles

    SciTech Connect (OSTI)

    Zhu, Zhengru; Li, Xinyong; Zhao, Qidong; Li, Yonghua; Sun, Caizhi; Cao, Yongqiang

    2013-08-01

    Graphical abstract: - Highlights: CuFe{sub 2}O{sub 4} nanocrystals were synthesized by a co-precipitation method. Ag/CuFe{sub 2}O{sub 4} catalyst was prepared by the wetness impregnation strategy. The structural properties of Ag/CuFe{sub 2}O{sub 4} were investigated by XRD, TEM, DRS, and XPS techniques. Ag/CuFe{sub 2}O{sub 4} has higher photocatalytic activity. - Abstract: In this work, CuFe{sub 2}O{sub 4} nanoparticles were synthesized by a chemical co-precipitation route. The Ag/CuFe{sub 2}O{sub 4} catalyst was prepared based on the CuFe{sub 2}O{sub 4} nanoparticles by the incipient wetness impregnation strategy, which showed excellent photoelectric property and catalytic activity. The structural properties of these samples were systematically investigated by X-ray powder diffraction (XRD), transmission electronic microscopy (TEM), UVvis diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FT-IR) techniques. The photo-induced charge separation in the samples was demonstrated by surface photovoltage (SPV) measurement. The photocatalytic degradation of 4-CP by the Ag/CuFe{sub 2}O{sub 4} and CuFe{sub 2}O{sub 4} samples were comparatively studied under xenon lamp irradiation. The results indicate that the Ag/CuFe{sub 2}O{sub 4} sample exhibited the higher efficiency for the degradation of 4-CP.

  16. Effect of the Keggin anions on assembly of Cu{sup I}-bis(tetrazole) thioether complexes containing multinuclear Cu{sup I}-cluster

    SciTech Connect (OSTI)

    Wang Xiuli; Gao Qiang; Tian Aixiang; Hu Hailiang; Liu Guocheng

    2012-03-15

    In order to investigate the effect of polyoxometalate (POM) on the assembly of transition metal-bis(tetrazole) thioether complexes, three new complexes based on different Keggin anions and multinuclear Cu{sup I}-cluster [Cu{sup I}{sub 12}(bmtr){sub 9}(HSiMo{sub 12}O{sub 40}){sub 4}] (1), [Cu{sup I}{sub 3}(bmtr){sub 3}(PM{sub 12}O{sub 40})] (M=W for 2; Mo for 3) (bmtr=1,3-bis(1-methyl-5-mercapto-1,2,3,4-tetrazole)propane), have been hydrothermally synthesized and characterized by routine physical methods and single crystal X-ray diffraction. In compound 1, two kinds of nanometer-scale tetranuclear subunits linked by [SiMo{sub 12}O{sub 40}]{sup 4-} polyanions assemble a (3, 4)-connected three-dimensional (3D) self-penetrating framework. Compounds 2 and 3 are isostructural, exhibiting a 1D chain with [PW{sub 12}O{sub 40}]{sup 3-}/[PMo{sub 12}O{sub 40}]{sup 3-} polyanions and trinuclear clusters arranging alternately. The distinct structural differences between these POM-based Cu{sup I}-bmtr complexes of 1 and 2/3 maybe rest on the contrast of Keggin-type polyoxometalate with different central heteroatoms, which have been discussed in detail. In addition, the electrochemical properties of the title complexes have been investigated. - Graphical abstract: Three new complexes based on different Keggin anions and multinuclear Cu{sup I}-cluster have been synthesized under hydrothermal conditions. The Keggin polyanions with different central heteroatoms play a key role. Highlights: Black-Right-Pointing-Pointer The flexible bis(tetrazole)-based thioether ligand with some advantages have been used. Black-Right-Pointing-Pointer The effect of Keggin anions with different central heteroatoms has been discussed in detail. Black-Right-Pointing-Pointer The electrochemical behaviors and electrocatalysis property have been investigated.

  17. Low temperature synthesis of Ru–Cu alloy nanoparticles with the compositions in the miscibility gap

    SciTech Connect (OSTI)

    Martynova, S.A.; Filatov, E.Yu.; Korenev, S.V.; Kuratieva, N.V.; Sheludyakova, L.A.; Plusnin, P.E.; Shubin, Yu.V.; Slavinskaya, E.M.; Boronin, A.I.

    2014-04-01

    A complex salt [Ru(NH{sub 3}){sub 5}Cl][Cu(C{sub 2}O{sub 4}){sub 2}H{sub 2}O]—the precursor of nanoalloys combining ruthenium and copper was prepared. It crystallizes in the monoclinic space group P2{sub 1}/n. Thermal properties of the prepared salt were examined in different atmospheres (helium, hydrogen, oxygen). Thermal decomposition of the precursor in inert atmosphere was thoroughly examined and the intermediate products were characterized. Experimental conditions for preparation of copper-rich (up to 12 at% of copper) metastable solid solution Cu{sub x}Ru{sub 1−x} (based on Ru structure) were optimized, what is in sharp contrast to the bimetallic miscibility gap known for the bulk counterparts in a wide composition range. Catalytic properties of copper–ruthenium oxide composite were tested in catalytic oxidation of CO. - Highlights: • We synthesized new precursor of CuRu metastable nanoalloys. • Thermal properties of the prepared salt were examined in different atmospheres. • Thermodestruction mechanism of precursor are studied. • Cu{sub 0.12}Ru{sub 0.88} nanoalloy with the compositions in the miscibility gap is obtained. • Catalytic conversion of CO on copper–ruthenium oxide composite were examined.

  18. Synthesis of YBa2CU3O7 using sub-atmospheric processing

    DOE Patents [OSTI]

    Wiesmann, Harold; Solovyov, Vyacheslav

    2004-09-21

    The present invention is a method of forming thick films of crystalline YBa.sub.2 Cu.sub.3 O.sub.7 that includes forming a precursor film comprising barium fluoride (BaF.sub.2), yttrium (Y) and copper (Cu). The precursor film is heat-treated at a temperature above 500.degree. C. in the presence of oxygen, nitrogen and water vapor at sub-atmospheric pressure to form a crystalline structure. The crystalline structure is then annealed at about 500.degree. C. in the presence of oxygen to form the crystalline YBa.sub.2 Cu.sub.3 O.sub.7 film. The YBa.sub.2 Cu.sub.3 O.sub.7 film formed by this method has a resistivity of from about 100 to about 600 .mu.Ohm-cm at room temperature and a critical current density measured at 77 K in a magnetic field of 1 Tesla of about 1.0.times.10.sup.5 Ampere per square centimeter (0.1 MA/cm.sup.2) or greater.

  19. Preparation of Bi-Sr-Ca-Cu-O superconductors from oxide-glass precursors

    DOE Patents [OSTI]

    Hinks, David G.; Capone, II, Donald W.

    1992-01-01

    A superconductor and precursor therefor from oxide mixtures of Ca, Sr, Bi and Cu. Glass precursors quenched to elevated temperatures result in glass free of crystalline precipitates having enhanced mechanical properties. Superconductors are formed from the glass precursors by heating in the presence of oxygen to a temperature below the melting point of the glass.

  20. Photoinduced Br Desorption from CsBr Thin Films Grown on Cu(100)

    SciTech Connect (OSTI)

    Halliday, Matthew T.; Joly, Alan G.; Hess, Wayne P.; Shluger, AL

    2015-10-22

    Thin films of CsBr deposited onto metals such as copper are potential photocathode materials for light sources and other applications. We investigate desorption dynamics of Br atoms from CsBr films grown on insulator (KBr, LiF) and metal (Cu) substrates induced by sub-bandgap 6.4 eV laser pulses. The experimental results demonstrate that the peak kinetic energy of Br atoms desorbed from CsBr/Cu films is much lower than that for the hyperthermal desorption from CsBr/LiF films. Kelvin probe measurements indicate negative charge at the surface following Br desorption from CsBr/Cu films. Our ab initio calculations of excitons at CsBr surfaces demonstrate that this behavior can be explained by an exciton model of desorption including electron trapping at the CsBr surface. Trapped negative charges reduce the energy of surface excitons available for Br desorption. We examine the electron-trapping characteristics of low-coordinated sites at the surface, in particular, divacancies and kink sites. We also provide a model of cation desorption caused by Franck-Hertz excitation of F centers at the surface in the course of irradiation of CsBr/Cu films. These results provide new insights into the mechanisms of photoinduced structural evolution of alkali halide films on metal substrates and activation of metal photocathodes coated with CsBr.

  1. Production of Cu-Al-Ni Shape Memory Alloys by Mechanical Alloy

    SciTech Connect (OSTI)

    Goegebakan, Musa; Soguksu, Ali Kemal; Uzun, Orhan; Dogan, Ali

    2007-04-23

    The mechanical alloying technique has been used to produce shape memory Cu83Al13Ni4 alloy. The structure and thermal properties were examined by using scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). The morphology of the surface suggests the presence of martensite.

  2. Local structure order in Pd78Cu6Si16 liquid

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Yue, G. Q.; Zhang, Y.; Sun, Y.; Shen, B.; Dong, F.; Wang, Z. Y.; Zhang, R. J.; Zheng, Y. X.; Kramer, M. J.; Wang, S. Y.; et al

    2015-02-05

    The short-range order (SRO) in Pd78Cu6Si16 liquid was studied by high energy x-ray diffraction and ab initio molecular dynamics (MD) simulations. The calculated pair correlation functions at different temperatures agree well with the experimental results. The partial pair correlation functions from ab intio MD simulations indicate that Si atoms prefer to be uniformly distributed while Cu atoms tend to aggregate. By performing structure analysis using Honeycutt-Andersen index, Voronoi tessellation, and atomic cluster alignment method, we show that the icosahedron and face-centered cubic SRO increase upon cooling. The dominant SRO is the Pd-centered Pd9Si2 motif, namely the structure of which motifmore » is similar to the structure of Pd-centered clusters in the Pd9Si2 crystal. The study further confirms the existence of trigonal prism capped with three half-octahedra that is reported as a structural unit in Pd-based amorphous alloys. The majority of Cu-centered clusters are icosahedra, suggesting that the presence of Cu is benefit to promote the glass forming ability.« less

  3. Phase transitions in delafossite CuLaO{sub 2} at high pressures

    SciTech Connect (OSTI)

    Salke, Nilesh P.; Rao, Rekha Gupta, M. K.; Mittal, R.; Garg, Alka B.; Achary, S. N.; Tyagi, A. K.

    2014-04-07

    Structural stability of a transparent conducting oxide CuLaO{sub 2} at high pressures is investigated using in-situ Raman spectroscopy, electrical resistance, and x-ray diffraction techniques. The present Raman investigations indicate a sequence of structural phase transitions at 1.8?GPa and 7?GPa. The compound remains in the first high pressure phase when pressure is released. Electrical resistance measurements carried out at high pressures confirm the second phase transition. These observations are further supported by powder x-ray diffraction at high pressures which also showed that a-axis is more compressible than c-axis in this compound. Fitting the pressure dependence of unit cell volume to 3{sup rd} order Birch-Murnaghan equation of state, zero pressure bulk modulus of CuLaO{sub 2} is determined to be 154(25) GPa. The vibrational properties in the ambient delafossite phase of CuLaO{sub 2} are investigated using ab-initio calculations of phonon frequencies to complement the Raman spectroscopic measurements. Temperature dependence of the Raman modes of CuLaO{sub 2} is investigated to estimate the anharmonicity of Raman modes.

  4. Energetics of the formation of Cu-Ag core–shell nanoparticles

    SciTech Connect (OSTI)

    Chandross, Michael

    2014-10-06

    Our work presents molecular dynamics and Monte Carlo simulations aimed at developing an understanding of the formation of core–shell Cu-Ag nanoparticles. The effects of surface and interfacial energies were considered and used to form a phenomenological model that calculates the energy gained upon the formation of a core–shell structure from two previously distinct, non-interacting nanoparticles. In most cases, the core–shell structure was found to be energetically favored. Specifically, the difference in energy as a function of the radii of the individual Cu and Ag particles was examined, with the assumption that a core–shell structure forms. In general, it was found that the energetic gain from forming such a structure increased with increasing size of the initial Ag particle. This result was interpreted as a result of the reduction in surface energy. Moreover, for two separate particles, both Cu and Ag contribute to the surface energy; however, for a core–shell structure, the only contribution to the surface energy is from the Ag shell and the Cu contribution is changed to a Cu–Ag interfacial energy, which is always smaller.

  5. Structural phase transition and phonon instability in Cu12Sb4S13

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    May, Andrew F.; Delaire, Olivier A.; Niedziela, Jennifer L.; Lara-Curzio, Edgar; Susner, Michael A.; Abernathy, Douglas L.; Kirkham, Melanie J.; McGuire, Michael A.

    2016-02-08

    In this study, a structural phase transition has been discovered in the synthetic tetrahedrite Cu12Sb4S13 at approximately 88 K. Upon cooling, the material transforms from its known cubic symmetry to a tetragonal unit cell that is characterized by an in-plane ordering that leads to a doubling of the unit cell volume. Specific heat capacity measurements demonstrate a hysteresis of more than two degrees in the associated anomaly. A similar hysteresis was observed in powder x-ray diffraction measurements, which also indicate a coexistence of the two phases, and together these results suggest a first-order transition. This structural transition coincides with amore » recently-reported metal-insulator transition, and the structural instability is related to the very low thermal conductivity κ in these materials. Inelastic neutron scattering was used to measure the phonon density of states in Cu12Sb4S13 and Cu10Zn2Sb4S13, both of which possess a localized, low-energy phonon mode associated with strongly anharmonic copper displacements that suppress κ. In Cu12Sb4S13, signatures of the phase transition are observed in the temperature dependence of the localized mode, which disappears at the structural transition. In contrast, in the cubic Zn-doped material, the mode is at slightly higher-energy but observable for all temperatures, though it softens upon cooling.« less

  6. X-ray imaging and controlled solidification of Al-Cu alloys toward microstructures by design

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Clarke, Amy J.; Tourret, Damien; Imhoff, Seth D.; Gibbs, Paul J.; Fezzaa, Kamel; Cooley, Jason C.; Lee, Wah -Keat; Deriy, Alex; Patterson, Brian M.; Papin, Pallas A.; et al

    2015-01-30

    X-ray imaging, which permits the microscopic visualization of metal alloy solidification dynamics, can be coupled with controlled solidification to create microstructures by design. This x-ray image shows a process-derived composite microstructure being made from a eutectic Al-17.1 at.%Cu alloy by successive solidification and remelting steps.

  7. Structural phase transition and phonon instabilities in Cu12Sb4S13

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    May, Andrew F.; Delaire, Olivier A.; Niedziela, Jennifer L.; Lara-Curzio, Edgar; Susner, Michael A.; Abernathy, Douglas L.; Kirkham, Melanie J.; McGuire, Michael A.

    2016-02-08

    In this study, a structural phase transition has been discovered in the synthetic tetrahedrite Cu12Sb4S13 at approximately 88 K. Upon cooling, the material transforms from its known cubic symmetry to a tetragonal unit cell that is characterized by an in-plane ordering that leads to a doubling of the unit cell volume. Specific heat capacity measurements demonstrate a hysteresis of more than two degrees in the associated anomaly. A similar hysteresis was observed in powder x-ray diffraction measurements, which also indicate a coexistence of the two phases, and together these results suggest a first-order transition. This structural transition coincides with amore » recently-reported metal-insulator transition, and the structural instability is related to the very low thermal conductivity κ in these materials. Inelastic neutron scattering was used to measure the phonon density of states in Cu12Sb4S13 and Cu10Zn2Sb4S13, both of which possess a localized, low-energy phonon mode associated with strongly anharmonic copper displacements that suppress κ. In Cu12Sb4S13, signatures of the phase transition are observed in the temperature dependence of the localized mode, which disappears at the structural transition. In contrast, in the cubic Zn-doped material, the mode is at slightly higher-energy but observable for all temperatures, though it softens upon cooling.« less

  8. Energetics of the formation of Cu-Ag core–shell nanoparticles

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Chandross, Michael

    2014-10-06

    Our work presents molecular dynamics and Monte Carlo simulations aimed at developing an understanding of the formation of core–shell Cu-Ag nanoparticles. The effects of surface and interfacial energies were considered and used to form a phenomenological model that calculates the energy gained upon the formation of a core–shell structure from two previously distinct, non-interacting nanoparticles. In most cases, the core–shell structure was found to be energetically favored. Specifically, the difference in energy as a function of the radii of the individual Cu and Ag particles was examined, with the assumption that a core–shell structure forms. In general, it was foundmore » that the energetic gain from forming such a structure increased with increasing size of the initial Ag particle. This result was interpreted as a result of the reduction in surface energy. Moreover, for two separate particles, both Cu and Ag contribute to the surface energy; however, for a core–shell structure, the only contribution to the surface energy is from the Ag shell and the Cu contribution is changed to a Cu–Ag interfacial energy, which is always smaller.« less

  9. Evaluation of high strength, high conductivity CuNiBe alloys for fusion energy applications

    SciTech Connect (OSTI)

    Zinkle, Steven J

    2014-06-01

    The unirradiated tensile properties for several different heats and thermomechanical treatment conditions of precipitation strengthened Hycon 3HPTM CuNiBe (Cu-2%Ni-0.35%Be in wt.%) have been measured over the temperature range of 20-500 C for longitudinal and long transverse orientations. The room temperature electrical conductivity has also been measured for several heats, and the precipitate microstructure was characterized using transmission electron microscopy. The CuNiBe alloys exhibit very good combination of strength and conductivity at room temperature, with yield strengths of 630-725 MPa and electrical conductivities of 65-72% International Annealed Copper Standard (IACS). The strength remained relatively high at all test temperatures, with yield strengths of 420-520 MPa at 500 C. However, low levels of ductility (<5% uniform elongation) were observed at test temperatures above 200-250 C, due to flow localization near grain boundaries (exacerbated by having only 10-20 grains across the gage thickness of the miniaturized sheet tensile specimens). Scanning electron microscopy observation of the fracture surfaces found a transition from ductile transgranular to ductile intergranular fracture with increasing test temperature. Fission neutron irradiation to a dose of ~0.7 displacements per atom (dpa) at temperatures between 100 and 240 C produced a slight increase in strength and a significant decrease in ductility. The measured tensile elongation increased with increasing irradiation temperature, with a uniform elongation of ~3.3% observed at 240 C. The electrical conductivity decreased slightly following irradiation, due to the presence of defect clusters and Ni, Zn, Co transmutation products. Considering also previously published fracture toughness data, this indicates that CuNiBe alloys have irradiated tensile and electrical properties comparable or superior to CuCrZr and oxide dispersion strengthened copper at temperatures <250 C, and may be an attractive candidate for certain fusion energy structural applications. Conversely, CuNiBe may not be preferred at intermediate temperatures of 250-500 C due to the poor ductility and fracture toughness of CuNiBe alloys at temperatures >250 C. The potential deformation mechanisms responsible for the transition from transgranular to intergranular fracture are discussed. The possible implications for other precipitation hardened alloys such as nickel based superalloys are briefly discussed.

  10. Synthesis, structure, and magnetic properties of a novel mixed-valence copper(I/II) phosphate, Cu{sub 2}PO{sub 4}

    SciTech Connect (OSTI)

    Etheredge, K.M.S.; Hwu, S.J.

    1995-09-27

    Via phase compatibility studies, a novel mixed-valence copper(I/II) phosphate, Cu{sub 2}PO{sub 4}, has been isolated from a direct reaction of Cu{sub 2}{sup I}O, Cu{sup II}O, and P{sub 2}O{sub 5} in fused silica. The single-crystal X-ray diffraction shows that the title compound crystallizes in a triclinic (P1) unit cell, with lattice dimensions a = 6.145(2) {angstrom}, b = 9.348(2) {angstrom}, c = 6.009(1) {angstrom}, {alpha} = 96.46(2){degrees}, {beta} = 100.16(2){degrees}, {gamma} = 73.97(2){degrees}, V = 325.8(1) {angstrom}{sup 3}; Z =4. The structure has been refined by the least-squares method to R = 0.019, R{sub w} = 0.030, and GOF = 1.43 for 128 variables. The four copper atoms in each asymmetric unit adopt three distorted coordination geometries that are consistent with the corresponding electronic states, e.g., square pyramidal Cu(1){sup II}O{sub 5}, octahedral Cu(2){sup II}O{sub 6}, and linear Cu(3,4){sup I}O{sub 2}. A low-dimensional framework exists consisting of arrays of nearly parallel CuO{sub 2} units which are separated by the nonmagnetic, closed-shell P{sup 5+} cation in PO{sub 4} tetrahedra. Closely spaced CuO{sub 2} chains and a relatively short Cu{sup I}-Cu{sup I} distance, e.g., 2.737 {angstrom} for Cu(3)-Cu(3), are attributed to the bond strength of the cross-linked PO{sub 4} tetrahedra. In the extended Cu(I/II)-O framework, short linkages of Cu{sup I}-O-Cu{sup II}-O-Cu{sup I} and Cu{sup II}-O-Cu{sup II}, composed of regular Cu-O bonds (1.86-1.99 {angstrom}), are interconnected through long Cu{sup II}-O bonds (2.36-2.74 {angstrom}). The magnetic measurements indicate that the Cu-O framework exhibits a spin 1/2 ground state and an antiferromagnetic ordering with a broad susceptibility maximum between 95 and 105 K. The results of stoichiometric synthesis, thermal analysis, and bond valence sum calculations of the title compound are also discussed.

  11. 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)

    2014-07-28

    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.

  12. Probing the Mechanism of Sodium Ion Insertion into Copper Antimony Cu2 Sb Anodes

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Baggetto, Loïc; Carroll, Kyler J.; Hah, Hien-Yoong; Johnson, Charles E.; Mullins, David R.; Unocic, Raymond R.; Johnson, Jacqueline A.; Meng, Ying Shirley; Veith, Gabriel M.

    2014-03-25

    Cycling Cu2Sb films with fluoroethylene carbonate additive drastically improves the capacity retention of the electrode compared to cycling in pure PC with about 250 mAh g-1 retained capacity for about two hundred cycles. TEM photographs reveal that the pristine films are formed of nanoparticles of 5-20 nm diameters. XRD results highlight that during the first discharge the reaction leads to the formation of Na3Sb via an intermediate amorphous phase. During charge, Na3Sb crystallites convert into an amorphous phase, which eventually crystallizes into Cu2Sb at full charge, indicating a high degree of structural reversibility. The subsequent discharge is marked by amore » new plateau around 0.5 V at low Na/Sb content which does not correspond to the formation of a crystalline phase. XAS data show that the fully discharged electrode material has interatomic distances matching those expected for the coexistence of Cu and Na3Sb nanodomains. At 1 V charge, the structure somewhat differs from that of Cu2Sb whereas at 2 V charge, when all Na is removed, the structure is significantly closer to that of the starting material. 121Sb Mössbauer spectroscopy isomer shifts of Cu2Sb powder (-9.67 mm s-1) and thin films (-9.65 mm s-1) are reported for the first time, and agree with the value predicted theoretically. At full discharge, an isomer shift (-8.10 mm s-1) rather close to that of a Na3Sb reference powder (-8.00 mm s-1) is measured, in agreement with the formation of Na3Sb domains evidenced by XRD and XAS data. The isomer shift at 1 V charge (-9.29 mm s-1) is close to that of the pristine material and the higher value is in agreement with the lack of full desodiation at 1 V.« less

  13. Probing the mechanism of sodium ion insertion into copper antimony Cu2Sb anodes

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Baggetto, Loic; Carroll, Kyler J.; Hah, Hien -Yoong; Johnson, Charles E.; Mullins, David R.; Unocic, Raymond R.; Johnson, Jacqueline A.; Meng, Ying Shirley; Veith, Gabriel M.

    2014-03-25

    Cycling Cu2Sb films with fluoroethylene carbonate additive drastically improves the capacity retention of the electrode compared to cycling in pure PC with about 250 mAh g-1 retained capacity for about two hundred cycles. TEM photographs reveal that the pristine films are formed of nanoparticles of 5-20 nm diameters. XRD results highlight that during the first discharge the reaction leads to the formation of Na3Sb via an intermediate amorphous phase. During charge, Na3Sb crystallites convert into an amorphous phase, which eventually crystallizes into Cu2Sb at full charge, indicating a high degree of structural reversibility. The subsequent discharge is marked by amore » new plateau around 0.5 V at low Na/Sb content which does not correspond to the formation of a crystalline phase. XAS data show that the fully discharged electrode material has interatomic distances matching those expected for the coexistence of Cu and Na3Sb nanodomains. At 1 V charge, the structure somewhat differs from that of Cu2Sb whereas at 2 V charge, when all Na is removed, the structure is significantly closer to that of the starting material. 121Sb Mössbauer spectroscopy isomer shifts of Cu2Sb powder (-9.67 mm s-1) and thin films (-9.65 mm s-1) are reported for the first time, and agree with the value predicted theoretically. At full discharge, an isomer shift (-8.10 mm s-1) rather close to that of a Na3Sb reference powder (-8.00 mm s-1) is measured, in agreement with the formation of Na3Sb domains evidenced by XRD and XAS data. As a result, the isomer shift at 1 V charge (-9.29 mm s-1) is close to that of the pristine material and the higher value is in agreement with the lack of full desodiation at 1 V.« less

  14. Potassium-induced effect on structure and chemical activity of CuxO/Cu(111) (x≤2) surface: A combined scanning tunneling microscopy and density functional theory study

    SciTech Connect (OSTI)

    Liu, Ping; An, Wei; Stacchiola, Dario; Xu, Fang

    2015-10-16

    Potassium (K) plays an essential role in promoting catalytic reaction in many established industrial catalytic processes. Here, we report a combined study using scanning tunneling microscopy (STM) and density functional theory (DFT) in understanding the effect of depositing K on the atomic and electronic structures as well as chemical activities of CuxO/Cu(111) (x≤2). The DFT calculations observe a pseudomorphic growth of K on CuxO/Cu(111) up to 0.19 monolayer (ML) of coverage, where K binds the surface via strong ionic interaction with chemisorbed oxygen and the relatively weak electrostatic interactions with copper ions, lower and upper oxygen on the CuxO rings. The simulated STM pattern based on the DFT results agrees well with the experimental observations. The deposited K displays great impact on the surface electronic structure of CuxO/Cu(111), which induces significant reduction in work function and leads to a strong electron polarization on the surface. The promotion of K on the surface binding properties is selective. It varies depending on the nature of adsorbates. According to our results, K has little effect on surface acidity, while it enhances the surface basicity significantly. As a consequence, the presence of K does not help for CO adsorption on CuxO/Cu(111), but being able to accelerate the activation of CO2. Thus, such promotion strongly depends on the combinations from both geometric and electronic effects. Our results highlight the origin of promoting effect of alkalis in the design of catalysts for the complex reactions.

  15. Synthesis, crystal and electronic structure, and physical properties of the new lanthanum copper telluride La{sub 3}Cu{sub 5}Te{sub 7}

    SciTech Connect (OSTI)

    Zelinska, Mariya; Assoud, Abdeljalil [Department of Chemistry, University of Waterloo, Waterloo, ON, Canada N2L 3G1 (Canada); Kleinke, Holger, E-mail: kleinke@uwaterloo.c [Department of Chemistry, University of Waterloo, Waterloo, ON, Canada N2L 3G1 (Canada)

    2011-03-15

    The new lanthanum copper telluride La{sub 3}Cu{sub 5-x}Te{sub 7} has been obtained by annealing the elements at 1073 K. Single-crystal X-ray diffraction studies revealed that the title compound crystallizes in a new structure type, space group Pnma (no. 62) with lattice dimensions of a=8.2326(3) A, b=25.9466(9) A, c=7.3402(3) A, V=1567.9(1) A{sup 3}, Z=4 for La{sub 3}Cu{sub 4.86(4)}Te{sub 7}. The structure of La{sub 3}Cu{sub 5-x}Te{sub 7} is remarkably complex. The Cu and Te atoms build up a three-dimensional covalent network. The coordination polyhedra include trigonal LaTe{sub 6} prisms, capped trigonal LaTe{sub 7} prisms, CuTe{sub 4} tetrahedra, and CuTe{sub 3} pyramids. All Cu sites exhibit deficiencies of various extents. Electrical property measurements on a sintered pellet of La{sub 3}Cu{sub 4.86}Te{sub 7} indicate that it is a p-type semiconductor in accordance with the electronic structure calculations. -- Graphical abstract: Oligomeric unit comprising interconnected CuTe{sub 3} pyramids and CuTe{sub 4} tetrahedra. Display Omitted Research highlights: {yields} La{sub 3}Cu{sub 5-x}Te{sub 7} adopts a new structure type. {yields} All Cu sites exhibit deficiencies of various extents. {yields} The coordination polyhedra include trigonal LaTe{sub 6} prisms, capped trigonal LaTe{sub 7} prisms, CuTe{sub 4} tetrahedra and CuTe{sub 3} pyramids. {yields} La{sub 3}Cu{sub 5-x}Te{sub 7} is a p-type semiconductor.

  16. CuCo2O4 ORR/OER Bi-functional catalyst: Influence of synthetic approach on performance

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Serov, Alexey; Andersen, Nalin I.; Roy, Aaron J.; Matanovic, Ivana; Artyushkova, Kateryna; Atanassov, Plamen

    2015-02-07

    A series of CuCo2O4 catalysts were synthesized by pore forming, sol-gel, spray pyrolysis and sacrificial support methods. Catalysts were characterized by XRD, SEM, XPS and BET techniques. The electrochemical activity for the oxygen reduction and oxygen evolution reactions (ORR and OER) was evaluated in alkaline media by RRDE. Density Functional Theory was used to identify two different types of active sites responsible for ORR/OER activity of CuCo2O4 and it was found that CuCo2O4 can activate the O-O bond by binding molecular oxygen in bridging positions between Co or Co and Cu atoms. It was found that the sacrificial support methodmore » (SSM) catalyst has the highest performance in both ORR and OER and has the highest content of phase-pure CuCo2O4. It was shown that the presence of CuO significantly decreases the activity in oxygen reduction and oxygen evolution reactions. As a result, the half-wave potential (E1/2) of CuCo2O4-SSM was found as 0.8 V, making this material a state-of-the-art, unsupported oxide catalyst.« less

  17. Application of glucose as a green capping agent and reductant to fabricate CuI micro/nanostructures

    SciTech Connect (OSTI)

    Tavakoli, Farnosh; Salavati-Niasari, Masoud; Ghanbari, Davood; Saberyan, Kamal; Hosseinpour-Mashkani, S. Mostafa

    2014-01-01

    Graphical abstract: - Highlights: CuI nanostructures were prepared via a simple precipitation method. Glucose as a green capping agent and reductant was applied. The effect of glucose concentration on the morphology of CuI was investigated. According to XRD results, pure cubic phase CuI have been formed by using glucose. - Abstract: In this work, CuI micro/nanostructures have been successfully prepared via a simple precipitation route at room temperature. By using glucose as a clean reducing agent with different concentrations, CuI micro/nanostructures with various morphologies were obtained. Besides glucose, Na{sub 2}SO{sub 3}, KBH{sub 4} and N{sub 2}H{sub 4}H{sub 2}O have been applied as reductant. X-ray diffraction (XRD), scanning electron microscopy (SEM), photoluminescence spectroscopy, X-ray energy dispersive spectroscopy (EDS) and Fourier transformed infrared (FT-IR) spectroscopy were used to characterize the as-produced CuI micro/nanostructures. According to the XRD results, it was found that pure cubic phase CuI have been formed by using glucose.

  18. Electrodeposition, characterization and morphological investigations of NiFe/Cu multilayers prepared by pulsed galvanostatic, dual bath technique

    SciTech Connect (OSTI)

    Esmaili, S.; Bahrololoom, M.E.; Kavanagh, K.L.

    2011-02-15

    NiFe/Cu multilayers were grown sequentially by pulsed electrodeposition on copper (Cu) substrates. The layers were prepared in galvanostatic mode using a dual bath technique. The morphology, thickness, roughness and composition of the layers were studied using scanning electron microscopy, scanning transmission electron microscopy with energy dispersive X-ray spectroscopy, X-ray diffraction and atomic force microscopy. Analysis showed that the resulting multilayers were continuous layers with a root mean square roughness of 30 nm and a grain size of 20-60 nm. The Cu substrate and the electrodeposited Cu layer were preferentially (200) oriented while the NiFe layers were polycrystalline but with a preferred (200) texture. The thinnest multilayers produced were 20/40, NiFe/Cu, respectively. - Research Highlights: {yields} Thin MLs of Cu and Py can be ED utilizing a pulsed-galvanostatic, DBT. {yields} The resulting multilayers were continuous layers with an rms of 30 nm. {yields} The smallest average thickness achieved by DBT was 40 nm/20 nm for Cu/NiFe.

  19. Chemical stability of highly (0001) textured Sm(CoCu){sub 5} thin films with a thin Ta capping layer

    SciTech Connect (OSTI)

    Zhao Haibao; Wang Hao; Liu Xiaoqi; Wang Jianping; Zhang Tao

    2011-04-01

    With the highest magnetocrystalline anisotropy constant (Ku) among practical magnetic materials, SmCo{sub 5} could be a very attractive candidate for future high areal density magnetic recording. However, its corrosion resistance is always a concern in recording media applications. In this paper, the chemical stability and microstructures of highly (0001) textured Sm(CoCu){sub 5} thin films with and without a 3 nm Ta capping layer were reported. For Sm(CoCu){sub 5} thin films without a capping layer, the coercivity decreases significantly (from 8kOe to 1kOe) within one month. Sm(CoCu){sub 5} thin films capped with a thin Ta layer (3 nm) behave differently. Even exposed to a laboratory environment (25 deg. C) over 3 years, the Ta-capped Sm(CoCu){sub 5} thin films are stable in terms of structural and magnetic properties, i.e., there were no changes in X-ray diffraction peaks and vibrating sample magnetometer hysteresis loops. Microstructure of Ta-capped Sm(CoCu){sub 5} thin films showed that Sm(CoCu){sub 5} formed a domelike particle assembly structure on a smooth Ru underlayer and were well covered by partially oxidized Ta capping layer, as shown by TEM cross-section micrographs. Accelerated corrosion treatment (130 deg. C, 95% relative humidity, 6 h) was performed on Ta-capped Sm(CoCu){sub 5} thin films. X-ray photoelectron spectroscopy (XPS) results showed that no Co was detected on the sample surface before the corrosion treatment, but strong XPS signals of CoOx and Co(OH)x were observed after treatment. Therefore, none of our Sm(CoCu){sub 5} thin films can pass the accelerated corrosion test. Hcp-phased CoPt-alloys are proposed as better capping materials for Sm(CoCu){sub 5} thin films in future high-density magnetic recording applications.

  20. FePtCu alloy thin films: Morphology, L1{sub 0} chemical ordering, and perpendicular magnetic anisotropy

    SciTech Connect (OSTI)

    Brombacher, C.; Schletter, H.; Daniel, M.; Matthes, P.; Joehrmann, N.; Makarov, D.; Hietschold, M.; Albrecht, M.; Maret, M.

    2012-10-01

    Rapid thermal annealing was applied to transform sputter-deposited Fe{sub 51}Pt{sub 49}/Cu bilayers into L1{sub 0} chemically ordered ternary (Fe{sub 51}Pt{sub 49}){sub 100-x}Cu{sub x} alloys with (001) texture on amorphous SiO{sub 2}/Si substrates. It was found that for thin film samples, which were processed at 600 Degree-Sign C for 30 s, the addition of Cu strongly favors the L1{sub 0} ordering and (001) texture formation. Furthermore, it could be revealed by transmission electron microscopy and electron backscatter diffraction that the observed reduction of the ordering temperature with Cu content is accompanied by an increased amount of nucleation sites forming L1{sub 0} ordered grains. The change of the structural properties with Cu content and annealing temperature is closely related to the magnetic properties. While an annealing temperature of 800 Degree-Sign C induces strong perpendicular magnetic anisotropy (PMA) in binary Fe{sub 51}Pt{sub 49} films, the addition of Cu systematically reduces the PMA. However, due to the enhancement of both the A1-L1{sub 0} phase transformation and the development of the (001) texture with increasing Cu content, lowering of the annealing temperature leads to a shift of the maximum perpendicular magnetic anisotropy towards alloys with higher Cu content. Thus, for an annealing temperature of 600 Degree-Sign C, the highest perpendicular magnetic anisotropy energy is found for the (Fe{sub 51}Pt{sub 49}){sub 91}Cu{sub 9} alloy. The smooth surface morphology, adjustable PMA, and high degree of intergranular exchange coupling make these films suitable for post-processing required for specific applications such as for sensorics or magnetic data storage.

  1. Synthesis and Evaluation of Cu/SAPO-34 Catalysts for NH3-SCR 2: Solid-state Ion Exchange and One-pot Synthesis

    SciTech Connect (OSTI)

    Gao, Feng; Walter, Eric D.; Washton, Nancy M.; Szanyi, Janos; Peden, Charles HF

    2015-01-01

    Cu-SAPO-34 catalysts are synthesized using two methods: solid-state ion exchange (SSIE) and one-pot synthesis. SSIE is conducted by calcining SAPO-34/CuO mixtures at elevated temperatures. For the one-pot synthesis method, Cu-containing chemicals (CuO and CuSO4) are added during gel preparation. A high-temperature calcination step is also needed for this method. Catalysts are characterized with surface area/pore volume measurements, temperature programmed reduction (TPR), electron paramagnetic resonance (EPR) and nuclear magnetic resonance (NMR) spectroscopies, and scanning electron microscopy (SEM). Catalytic properties are examined using standard ammonia selective catalytic reduction (NH3-SCR) and ammonia oxidation reactions. In Cu-SAPO-34 samples formed using SSIE, Cu presents both as isolated Cu2+ ions and unreacted CuO. The former is highly active and selective in NH3-SCR, while the latter catalyzes a side reaction; notably, the non-selective oxidation of NH3 above 350 ºC. Using the one-pot method followed by a high-temperature aging treatment, it is possible to form Cu SAPO-34 samples with predominately isolated Cu2+ ions at low Cu loadings. However at much higher Cu loadings, isolated Cu2+ ions that bind weakly with the CHA framework and CuO clusters also form. These Cu moieties are very active in catalyzing non-selective NH3 oxidation above 350 ºC. Low-temperature reaction kinetics indicate that Cu-SAPO-34 samples formed using SSIE have core-shell structures where Cu is enriched in the shell layers; while Cu is more evenly distributed within the one-pot samples. Reaction kinetics also suggest that at low temperatures, the local environment next to Cu2+ ion centers plays little role on the overall catalytic properties. The authors gratefully acknowledge the US Department of Energy (DOE), Energy Efficiency and Renewable Energy, Vehicle Technologies Office for the support of this work. The research described in this paper was performed at the Environmental Molecular Sciences Laboratory (EMSL), a national scientific user facility sponsored by the DOE’s Office of Biological and Environmental Research and located at Pacific Northwest National Laboratory (PNNL). PNNL is operated for the US DOE by Battelle under contract number DE-AC05-76RL01830. The authors also thank Shari Li (PNNL) for surface area/pore volume measurements, and Bruce W. Arey (PNNL) for SEM measurements. Discussions with Drs. A. Yezerets, K. Kamasamudram, J.H. Li, N. Currier and J.Y. Luo from Cummins, Inc. and H.Y. Chen and H. Hess from Johnson-Matthey are greatly appreciated.

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

    SciTech Connect (OSTI)

    Kalay, Ilkay

    2010-12-15

    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.

  3. Method for preparation of textured YBa.sub.2 Cu.sub.3 O.sub.x superconductor

    DOE Patents [OSTI]

    Selvamanickam, Venkat; Goyal, Amit; Kroeger, Donald M.

    1998-01-01

    The present invention relate to textured YBa.sub.2 Cu.sub.3 O.sub.x (Y-123) superconductors and a process of preparing them by directional recrystallization of compacts fabricated from quenched YBCO powders at temperatures about 100.degree. C. below the peritectic temperature to provide a superconductor where more than 75% of the YBa.sub.2 Cu.sub.3 O.sub.x phase is obtained without any Y.sub.2 BaCuO.sub.5 .

  4. Pulse studies to decipher the role of surface morphology in CuO/CeO₂ nanocatalysts for the water gas shift reaction

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Rodriguez, Jose A.; Zhao, Fuzhen; Liu, Zongyuan; Xu, Wenqian; Yao, Siyu; Si, Rui; Johnston-Peck, Aaron C.; Martinez-Arias, Arturo; Hanson, Jonathan C.; Senanayake, Sanjaya D.

    2015-01-23

    The water-gas shift reaction (WGS, CO + H₂O → CO₂) was studied over CuO/CeO₂ catalysts with two different ceria particle morphohologies, in the form of nanospheres (ns) and nanocubes (nc). To understand the strong dependence of the WGS reaction activity on the ceria nanoshapes, pulses of CO (without and with water vapor) were employed during in situ X-ray diffraction (XRD) and X-ray absoprtion near edge structure (XANES) measurements done to characterize the catalysts. The results showed that CuO/CeO₂ (ns) exhibited a substantially better activity than CuO/CeO₂ (nc). The higher activity was associated with the unique properties of CuO/CeO₂ (ns), suchmore » as the easier reduction of highly dispersed CuO to metallic Cu, the stability of metallic Cu and a larger concentration Ce³⁺ in CeO₂ (ns).« less

  5. Effects of substrate temperature and Cu underlayer thickness on the formation of SmCo{sub 5}(0001) epitaxial thin films

    SciTech Connect (OSTI)

    Ohtake, Mitsuru; Nukaga, Yuri; Futamoto, Masaaki; Kirino, Fumiyoshi

    2010-05-15

    SmCo{sub 5}(0001) epitaxial thin films were prepared on Cu(111) underlayers heteroepitaxially grown on Al{sub 2}O{sub 3}(0001) single-crystal substrates by molecular beam epitaxy. The effects of substrate temperature and Cu underlayer thickness on the crystallographic properties of SmCo{sub 5}(0001) epitaxial films were investigated. The Cu atoms of underlayer diffuse into the SmCo{sub 5} film and substitute the Co sites in SmCo{sub 5} structure forming an alloy compound of Sm(Co,Cu){sub 5}. The ordered phase formation is enhanced with increasing the substrate temperature and with increasing the Cu underlayer thickness. The Cu atom diffusion into the SmCo{sub 5} film is assisting the formation of Sm(Co,Cu){sub 5} ordered phase.

  6. Pulse studies to decipher the role of surface morphology in CuO/CeO₂ nanocatalysts for the water gas shift reaction

    SciTech Connect (OSTI)

    Rodriguez, Jose A.; Zhao, Fuzhen; Liu, Zongyuan; Xu, Wenqian; Yao, Siyu; Si, Rui; Johnston-Peck, Aaron C.; Martinez-Arias, Arturo; Hanson, Jonathan C.; Senanayake, Sanjaya D.

    2015-01-23

    The water-gas shift reaction (WGS, CO + H₂O → CO₂) was studied over CuO/CeO₂ catalysts with two different ceria particle morphohologies, in the form of nanospheres (ns) and nanocubes (nc). To understand the strong dependence of the WGS reaction activity on the ceria nanoshapes, pulses of CO (without and with water vapor) were employed during in situ X-ray diffraction (XRD) and X-ray absoprtion near edge structure (XANES) measurements done to characterize the catalysts. The results showed that CuO/CeO₂ (ns) exhibited a substantially better activity than CuO/CeO₂ (nc). The higher activity was associated with the unique properties of CuO/CeO₂ (ns), such as the easier reduction of highly dispersed CuO to metallic Cu, the stability of metallic Cu and a larger concentration Ce³⁺ in CeO₂ (ns).

  7. An in-situ phosphorus source for the synthesis of Cu3P and the subsequent conversion to Cu3PS4 nanoparticle clusters

    SciTech Connect (OSTI)

    Sheets, Erik J.; Stach, Eric A.; Yang, Wei -Chang; Balow, Robert B.; Wang, Yunjie; Walker, Bryce C.; Agrawal, Rakesh

    2015-09-20

    The search for alternative earth abundant semiconducting nanocrystals for sustainable energy applications has brought forth the need for nanoscale syntheses beyond bulk synthesis routes. Of particular interest are metal phosphides and derivative I-V-VI chalcogenides including copper phosphide (Cu3P) and copper thiophosphate (Cu3PS4). Herein, we report a one-pot, solution-based synthesis of Cu3P nanocrystals utilizing an in-situ phosphorus source: phosphorus pentasulfide (P2S5) in trioctylphosphine (TOP). By injecting this phosphorus source into a copper solution in oleylamine (OLA), uniform and size controlled Cu3P nanocrystals with a phosphorous-rich surface are synthesized. The subsequent reaction of the Cu3P nanocrystals with decomposing thiourea forms nanoscale Cu3PS4 particles having p-type conductivity and an effective optical band gap of 2.36 eV.

  8. Precipitate size refinement by CeO{sub 2} and Y{sub 2}BaCuO{sub 5} additions in directionally solidified YBa{sub 2}Cu{sub 3}O{sub 7}

    SciTech Connect (OSTI)

    Vilalta, N.; Sandiumenge, F.; Pinol, S.; Obradors, X.

    1997-01-01

    Directional solidification of YBa{sub 2}Cu{sub 3}O{sub 7} has been carried out through a Bridgman technique, and the influence of Y{sub 2}BaCuO{sub 5} and CeO{sub 2} additives on the size of Y{sub 2}BaCuO{sub 5} precipitates has been investigated. It is demonstrated in this work that the most efficient procedure to reduce the size of the Y{sub 2}BaCuO{sub 5} precipitates is to increase the concentration of nucleation centers present in the peritectic decomposition of YBa{sub 2}Cu{sub 3}O{sub 7{minus}x}. A small concentration (0.3{endash}1 wt.{percent}) of CeO{sub 2} has a strong influence on the solidification process and on the size of Y{sub 2}BaCuO{sub 5} precipitates. It is shown that when CeO{sub 2} is added, further refinement of the size of precipitates results from the formation of nanometric Y{sub 2}O{sub 3} particles which further enhance the multinucleation effect. We have also observed that coarsening effects are avoided with CeO{sub 2} additives. {copyright} {ital 1997 Materials Research Society.}

  9. Size and alloying induced shift in core and valence bands of Pd-Ag and Pd-Cu nanoparticles

    SciTech Connect (OSTI)

    Sengar, Saurabh K.; Mehta, B. R.; Govind

    2014-03-28

    In this report, X-ray photoelectron spectroscopy studies have been carried out on Pd, Ag, Cu, Pd-Ag, and Pd-Cu nanoparticles having identical sizes corresponding to mobility equivalent diameters of 60, 40, and 20 nm. The nanoparticles were prepared by the gas phase synthesis method. The effect of size on valence and core levels in metal and alloy nanoparticles has been studied by comparing the values to those with the 60 nm nanoparticles. The effect of alloying has been investigated by comparing the valence and core level binding energies of Pd-Cu and Pd-Ag alloy nanoparticles with the corresponding values for Pd, Ag, and Cu nanoparticles of identical sizes. These effects have been explained in terms of size induced lattice contractions, alloying induced charge transfer, and hybridization effects. The observation of alloying and size induced binding energy shifts in bimetallic nanoparticles is important from the point of view of hydrogen reactivity.

  10. Comparison of CsBr and KBr coated Cu photocathodes: Effects of laser irradiation and work function changes

    SciTech Connect (OSTI)

    He, Weidong; VilayurGanapathy, Subramanian; Joly, Alan G.; Droubay, Timothy C.; Chambers, Scott A.; Maldonado, Juan R.; Hess, Wayne P.

    2013-02-20

    Thin films (7 nm layers) of CsBr and KBr were deposited on Cu(100) to investigate photoemission properties of these potential photocathode materials. After thin film deposition and prolonged laser ultraviolet (UV) irradiation (266 nm picosecond laser) photoemission quantum efficiency increases by factors of 26 and 77 for KBr/Cu(100) and CsBr/Cu(100) photocathodes, respectively. Immediately following thin film deposition, a decrease in work function is observed, compared to bare Cu, in both cases. Quantum efficiency enhancements are attributed to the decrease in photocathode work function, due to the deposition of alkali halide thin films, and photo-induced processes, that introduce defect states into the alkali halide bandgap, induced by UV laser irradiation. It is possible that alkali metal formation occurs during UV irradiation and that this further contributes to photoemission enhancement. Our results suggest that KBr, a relatively stable alkali-halide, has potential for photocathode applications.

  11. Millimeter size single crystals of superconducting YBa[sub 2]Cu[sub 3]O[sub x

    DOE Patents [OSTI]

    Damento, M.A.; Gschneidner, K.A. Jr.

    1989-04-25

    A method of growing large, up to 1 mm size single crystals of superconducting YBa[sub 2]Cu[sub 3]O[sub x], wherein x equals from 6.5 to 7.2 is disclosed.

  12. The equilibrium vortex melting transition in YBa{sub 2}Cu{sub 3}O{sub 7}

    SciTech Connect (OSTI)

    Crabtree, G.W.; Welp, U.; Kwok, W.K.; Fendrich, J.A.; Veal, B.W.

    1996-10-01

    The dynamic and thermodynamic experimental evidence supporting first order vortex melting in clean crystals of YBa{sub 2}Cu{sub 3}O{sub 7} is reviewed.

  13. Nuclear matter effects on J/? production in asymmetric Cu+Au collisions at ?SNN=200 GeV

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Adare, A.

    2014-12-18

    We report on J/? production from asymmetric Cu+Au heavy-ion collisions at ?sNN =200 GeV at the Relativistic Heavy Ion Collider at both forward (Cu-going direction) and backward (Au-going direction) rapidities. The nuclear modification of J/? yields in Cu+Au collisions in the Au-going direction is found to be comparable to that in Au+Au collisions when plotted as a function of the number of participating nucleons. In the Cu-going direction, J/? production shows a stronger suppression. This difference is comparable in magnitude and has the same sign as the difference expected from shadowing effects due to stronger low-x gluon suppression in themorelarger Au nucleus. The relative suppression is opposite to that expected from hot nuclear matter dissociation, since a higher energy density is expected in the Au-going direction.less

  14. A three-dimensional Macroporous Cu/SnO2 composite anode sheet prepared via a novel method

    SciTech Connect (OSTI)

    Xu, Wu; Canfield, Nathan L.; Wang, Deyu; Xiao, Jie; Nie, Zimin; Zhang, Jiguang

    2010-11-01

    Macroporous Cu/SnO2 composite anode sheets were prepared by a novel method which is based on slurry blending, tape casting, sintering, and reducing of metal oxides. Such composite Cu/SnO2 anode sheets have no conducting carbons and binders, and show improved discharge capacity and cycle life than the SnO2 electrode from conventional tape-casting method on Cu foil. This methodology produces limited wastes and is also adaptable to many other materials. It is easy for industrial scale production. With the optimization of particle size of the metal oxide, pore size, pore volume and other factors, this kind of macroporous Cu/SnO2 composite anode sheets could give significantly improved capacity and cycle life.

  15. Comment on 'The diatomic dication CuZn{sup 2+} in the gas phase' [J. Chem. Phys. 135, 034306 (2011)

    SciTech Connect (OSTI)

    Fiser, Jiri; Diez, Reinaldo Pis; Franzreb, Klaus; Alonso, Julio A.

    2013-02-21

    In this Comment, the density functional theory (DFT) calculations carried out by Diez et al. [J. Chem. Phys. 135, 034306 (2011)] are revised within the framework of the coupled-cluster single double triple method. These more sophisticated calculations allow us to show that the {sup 2}{Sigma}{sup +} electronic ground state of CuZn{sup 2+}, characterized as the metastable ground state by DFT calculations, is a repulsive state instead. The {sup 2}{Delta} and {sup 2}{Pi} metastable states of CuZn{sup 2+}, on the other hand, should be responsible for the formation mechanism of the dication through the near-resonant electron transfer CuZn{sup +}+ Ar{sup +}{yields} CuZn{sup 2+}+ Ar reaction.

  16. Resonant elastic soft x-ray scattering in oxygen-ordered YBa2Cu3O6...

    Office of Scientific and Technical Information (OSTI)

    Resonant elastic soft x-ray scattering in oxygen-ordered YBa2Cu3O6+ Citation Details In-Document Search Title: Resonant elastic soft x-ray scattering in oxygen-ordered...

  17. Investigation of the oxidation states of Cu additive in colored borosilicate glasses by electron energy loss spectroscopy

    SciTech Connect (OSTI)

    Yang, Guang Cheng, Shaodong; Li, Chao; Ma, Chuansheng; Zhong, Jiasong; Xiang, Weidong; Wang, Zhao

    2014-12-14

    Three optically transparent colorful (red, green, and blue) glasses were synthesized by the sol-gel method. Nano-sized precipitates were found in scanning electron microscopy images. The precipitates were analyzed by transmission electron microscopy (TEM) and high resolution TEM. The measured lattice parameters of these precipitates were found to fit the metallic copper in red glass but deviate from single valenced Cu oxides in green and blue glasses. The chemistry of these nano-sized particles was confirmed by electron energy loss spectroscopy (EELS). By fitting the EELS spectra obtained from the precipitates with the linear combination of reference spectra from Cu reference compounds, the oxidation states of Cu in the precipitates have been derived. First principle calculations suggested that the Cu nano-particles, which are in the similar oxidation states as our measurement, would show green color in the visible light range.

  18. Millimeter size single crystals of superconducting YBa.sub.2 Cu.sub.3 O.sub .

    DOE Patents [OSTI]

    Damento, Michael A. (Ames, IA); Gschneidner, Jr., Karl A. (Ames, IA)

    1989-04-25

    A method of growing large, up to 1 mm size single crystals of superconducting YBa.sub.2 Cu.sub.3 O.sub.x, wherein x equals from 6.5 to 7.2.

  19. Characterization and oxidation states of Cu and Pd in Pd?CuO/ZnO/ZrO[subscript 2] catalysts for hydrogen production by methanol partial oxidation

    SciTech Connect (OSTI)

    Schuyten, S.; Guerrero, S.; Miller, J.T.; Shibatae, T.; Wolf, E.E.

    2009-01-30

    Copper and zinc oxide based catalysts prepared by coprecipitation were promoted with palladium and ZrO{sub 2}, and their activity and selectivity for methanol oxidative reforming was measured and characterized by N{sub 2}O decomposition, X-ray absorption spectroscopy, BET, X-ray photoelectron spectroscopy, X-ray diffraction, and temperature programmed reduction. Addition of ZrO{sub 2} increased copper dispersion and surface area, with little effect on activity, while palladium promotion significantly enhanced activity with little change of the catalytic structure. A catalyst promoted with both ZrO{sub 2} and palladium yielded hydrogen below 150 C. EXAFS results under reaction conditions showed that the oxidation state of copper was influenced by palladium in the catalyst bulk. A palladium promoted catalyst contained 90% Cu{sup 0}, while the copper in an unpromoted catalyst was 100% Cu{sup 1+} at the same temperature. Palladium preferentially forms an unstable alloy with copper instead of zinc during reduction, which persists during reaction regardless of copper oxidation state. A 100-h time on stream activity measurement showed growth in copper crystallites and change in copper oxidation state resulting in decreasing activity and selectivity. A kinetic model of the reaction pathway showed that palladium and ZrO{sub 2} promoters lower the activation energy of methanol combustion and steam reforming reactions.

  20. Structural, elastic, electronic, magnetic and vibrational properties of CuCoMnGa under pressure

    SciTech Connect (OSTI)

    İyigör, Ahmet; Uğur, Şule

    2014-10-06

    First principles calculations for the structural, electronic, elastic and phonon properties of the cubic quaternary heusler alloy CuCoMnGa on pressure have been reported by density functional theory (DFT) within generalized gradient approximation (GGA). The calculated values of the elastic constants were used for estimations of the Debye temperatures, the bulk modulus, the shear modulus, the young modulus E, the poisson's ratio σ and the B/G ratio. The elastic constants satisfy all of the mechanical stability criteria. The electronic structures of the ferromagnetic configuration for CuCoMnGa have a metallic character. The estimated magnetic moment per formula unit is 3.76 μ{sub B}. The phonon dispersion is studied using the supercell approach, and the stable nature at 0.2 GPa pressure is observed.

  1. Deformation behavior of Nb nanowires in TiNiCu shape memory alloy matrix

    SciTech Connect (OSTI)

    Jiang, Daqiang; Liu, Yinong; Yu, Cun; Liu, Weilong; Yang, Hong; Jiang, Xiaohua; Ren, Yang; Cui, Lishan

    2015-08-18

    An in-situ nanowire Nb/TiNiCu composite is fabricated based on the concept of strain under-matching between a phase transforming matrix and high strength nanomaterials. The deformation behavior of the Nb nanowire was investigated by means of in-situ synchrotron X-ray diffraction when the TiNiCu matrix underwent different deformation modes. The maximum lattice strain of the Nb nanowires was about 5% when the matrix deformed via martensitic transformation or 1% when deforming plastically by dislocation slip. As a result, the Nb nanowires showed a lattice strain of 3.5% when the matrix deformed in the mixed mode of plastic deformation and martensitic transformation, which means that the occurrence of plastic deformation does not impede load transfer from the matrix to the nanowires.

  2. Crystallization from high temperature solutions of Si in Cu/Al solvent

    DOE Patents [OSTI]

    Ciszek, Theodore F.; Wang, Tihu

    1996-01-01

    A liquid phase epitaxy method for forming thin crystalline layers of device quality silicon having less than 3.times.10.sup.16 Cu atoms/cc impurity, comprising: preparing a saturated liquid solution of Si in a Cu/Al solvent at about 20 to about 40 at. % Si at a temperature range of about 850.degree. to about 1100.degree. C. in an inert gas; immersing or partially immersing a substrate in the saturated liquid solution; super saturating the solution by lowering the temperature of the saturated solution; holding the substrate in the saturated solution for a period of time sufficient to cause Si to precipitate out of solution and form a crystalline layer of Si on the substrate; and withdrawing the substrate from the solution.

  3. Crystallization from high temperature solutions of Si in Cu/Al solvent

    DOE Patents [OSTI]

    Ciszek, T.F.; Wang, T.

    1996-08-13

    A liquid phase epitaxy method is disclosed for forming thin crystalline layers of device quality silicon having less than 3{times}10{sup 16} Cu atoms/cc impurity, comprising: preparing a saturated liquid solution of Si in a Cu/Al solvent at about 20 to about 40 at. % Si at a temperature range of about 850 to about 1100 C in an inert gas; immersing or partially immersing a substrate in the saturated liquid solution; super saturating the solution by lowering the temperature of the saturated solution; holding the substrate in the saturated solution for a period of time sufficient to cause Si to precipitate out of solution and form a crystalline layer of Si on the substrate; and withdrawing the substrate from the solution. 3 figs.

  4. Effects of charge inhomogeneities on elementary excitations in La2-xSrxCuO₄

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Park, S. R.; Hamann, A.; Pintschovius, L.; Lamago, D.; Khaliullin, G.; Fujita, M.; Yamada, K.; Gu, G. D.; Tranquada, J. M.; Reznik, D.

    2011-12-12

    Purely local experimental probes of many copper oxide superconductors show that their electronic states are inhomogeneous in real space. For example, scanning tunneling spectroscopic imaging shows strong variations in real space, and according to nuclear quadrupole resonance (NQR) studies, the charge distribution in the bulk varies on the nanoscale. However, the analysis of the experimental results utilizing spatially averaged probes often ignores this fact. We have performed a detailed investigation of the doping dependence of the energy and linewidth of the zone-boundary Cu-O bond-stretching vibration in La2-xSrxCuO₄ by inelastic neutron scattering. Both our results as well as previously reported angle-dependentmore » momentum widths of the electronic spectral function detected by angle-resolved photoemission can be reproduced by including the same distribution of local environments extracted from the NQR analysis.« less

  5. Effective activation energy in the Bi-Sr-Ca-Cu-O systems

    SciTech Connect (OSTI)

    Sengupta, S.; Shi, D.; Wang, Z.; Smith, M.; McGinn, P.J.

    1992-08-01

    Magnetic relaxation in the Bi-Sr-Ca-Cu-O systems has been investigated in a wide temperature regime. Previously reported studies of the effective activation energy, U, have been controversial in terms of temperature and field dependence of the critical current density, j{sub c}. We have considered the temperature dependence of j{sub c} and constructed the U-j (or M) curves for the Bi-Sr-Ca-Cu-O system. We found that at a constant driving force and temperature, U is considerably higher for 2245 samples than for 2223 samples. This enhancement can be attributed to the flux pinning from finely dispersed calcium- and copper- rich precipitates.

  6. Solidification analysis of a centrifugal atomizer using the Al-32.7wt.% Cu alloy

    SciTech Connect (OSTI)

    Osborne, M.G.

    1998-02-23

    A centrifugal atomizer (spinning disk variety) was designed and constructed for the production of spherical metal powders, 100--1,000 microns in diameter in an inert atmosphere. Initial atomization experiments revealed the need for a better understanding of how the liquid metal was atomized and how the liquid droplets solidified. To investigate particle atomization, Ag was atomized in air and the process recorded on high-speed film. To investigate particle solidification, Al-32.7 wt.% Cu was atomized under inert atmosphere and the subsequent particles were examined microscopically to determine solidification structure and rate. This dissertation details the experimental procedures used in producing the Al-Cu eutectic alloy particles, examination of the particle microstructures, and determination of the solidification characteristics (e.g., solidification rate) of various phases. Finally, correlations are proposed between the operation of the centrifugal atomizer and the observed solidification spacings.

  7. Effective activation energy in the Bi-Sr-Ca-Cu-O systems

    SciTech Connect (OSTI)

    Sengupta, S.; Shi, D.; Wang, Z.; Smith, M. ); McGinn, P.J. . Dept. of Electrical Engineering)

    1992-08-01

    Magnetic relaxation in the Bi-Sr-Ca-Cu-O systems has been investigated in a wide temperature regime. Previously reported studies of the effective activation energy, U, have been controversial in terms of temperature and field dependence of the critical current density, j[sub c]. We have considered the temperature dependence of j[sub c] and constructed the U-j (or M) curves for the Bi-Sr-Ca-Cu-O system. We found that at a constant driving force and temperature, U is considerably higher for 2245 samples than for 2223 samples. This enhancement can be attributed to the flux pinning from finely dispersed calcium- and copper- rich precipitates.

  8. Synthesis, characterization and physical properties of Al-Cu-Fe quasicrystalline plasma sprayed coatings

    SciTech Connect (OSTI)

    Daniel, S.

    1995-11-09

    Our lab has been working with plasma spraying of both high pressure gas atomized (HPGA) and cast and crushed quasicrystal powders. A major component of this research includes comparative studies of PAS coatings formed with starting powders prepared by both techniques. In addition, a thorough investigation of the effects of starting powder particle size on coating microstructure is included. During the course of the overall research, an interest developed in forming Al-Cu-Fe materials with finer grain sizes. Therefore, a brief study was performed to characterize the effect of adding boron to Al-Cu-Fe materials prepared by different techniques. In addition to characterizing the microstructural features of the above materials, oxidation and wear behavior was also examined.

  9. Unique properties of CuZrAl bulk metallic glasses induced by microalloying

    SciTech Connect (OSTI)

    Huang, B.; Bai, H. Y.; Wang, W. H.

    2011-12-15

    We studied the glass forming abilities (GFA), mechanical, and physical properties of (CuZr){sub 92.5}Al{sub 7}X{sub 0.5} (X = La, Sm, Ce, Gd, Ho, Y, and Co) bulk metallic glasses (BMGs). We find that the GFA, mechanical, and physical properties can be markedly changed and modulated by the minor rare earth addition. The Kondo screening effect is found to exist in (CuZr){sub 92.5}Al{sub 7}Ce{sub 0.5} BMG at low temperatures and the Schottky effect exists in all the rare earth element doped BMGs. Our results indicate that the minor addition is an effective way for modulating and getting desirable properties of the BMGs. The mechanisms of the effects of the addition are discussed. The results have implications for the exploration of metallic glasses and for improving the mechanical and low temperature physical properties of BMGs.

  10. Single crystal growth and characterization of the large-unit-cell compound Cu13Ba

    SciTech Connect (OSTI)

    Jesche, Anton; Budko, Serguei L.; Canfield, Paul C.

    2013-10-31

    Single crystals of Cu13Ba were successfully grown out of BaCu self flux. Temperature dependent magnetization, M (T ), electrical resistivity, ?(T)?(T), and specific heat, Cp(T)Cp(T), data are reported. Isothermal magnetization measurements, M(H)M(H), show clear de Haas-van Alphen oscillations at T = 2 K for applied fields as low as View the MathML source?0H=1T. An anomalous behavior of the magnetic susceptibility is observed up to T ? 50 K reflecting the effect of de Haas-van Alphen oscillations at fairly high temperatures. The field- and temperature-dependencies of the magnetization indicate the presence of diluted magnetic impurities with a concentration of the order of 0.01 at.%. Accordingly, the minimum and lower temperature rise observed in the electrical resistivity at and below T = 15 K is attributed to the Kondo-impurity effect.

  11. Density-functional Monte-Carlo simulation of CuZn order-disorder transition

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Khan, Suffian N.; Eisenbach, Markus

    2016-01-25

    We perform a Wang-Landau Monte Carlo simulation of a Cu0.5Zn0.5 order-disorder transition using 250 atoms and pairwise atom swaps inside a 5 x 5 x 5 BCC supercell. Each time step uses energies calculated from density functional theory (DFT) via the all-electron Korringa-Kohn- Rostoker method and self-consistent potentials. Here we find CuZn undergoes a transition from a disordered A2 to an ordered B2 structure, as observed in experiment. Our calculated transition temperature is near 870 K, comparing favorably to the known experimental peak at 750 K. We also plot the entropy, temperature, specific-heat, and short-range order as a function ofmore » internal energy.« less

  12. The spin-dependent transport of Co-encapsulated Si nanotubes contacted with Cu electrodes

    SciTech Connect (OSTI)

    Guo, Yan-Dong; Yan, Xiao-Hong; Xiao, Yang

    2014-02-10

    Unlike carbon nanotubes, silicon ones are hard to form. However, they could be stabilized by metal-encapsulation. Using first-principles calculations, we investigate the spin-dependent electronic transport of Co-encapsulated Si nanotubes, which are contacted with Cu electrodes. For the finite tubes, as the tube-length increases, the transmission changes from spin-unpolarized to spin-polarized. Further analysis shows that, not only the screening of electrodes on Co's magnetism but also the spin-asymmetric Co-Co interactions are the physical mechanisms. As Cu and Si are the fundamental elements in semiconductor industry, our results may throw light on the development of silicon-based spintronic devices.

  13. Computer modeling of Y-Ba-Cu-O thin film deposition and growth

    SciTech Connect (OSTI)

    Burmester, C.; Gronsky, R. ); Wille, L. . Dept. of Physics)

    1991-07-01

    The deposition and growth of epitaxial thin films of YBa{sub 2}Cu{sub 3}O{sub 7} are modeled by means of Monte Carlo simulations of the deposition and diffusion of Y, Ba, and Cu oxide particles. This complements existing experimental characterization techniques to allow the study of kinetic phenomena expected to play a dominant role in the inherently non-equilibrium thin film deposition process. Surface morphologies and defect structures obtained in the simulated films are found to closely resemble those observed experimentally. A systematic study of the effects of deposition rate and substrate temperature during in-situ film fabrication reveals that the kinetics of film growth can readily dominate the structural formation of the thin film. 16 refs., 4 figs.

  14. Deformation behavior of Nb nanowires in TiNiCu shape memory alloy matrix

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Jiang, Daqiang; Liu, Yinong; Yu, Cun; Liu, Weilong; Yang, Hong; Jiang, Xiaohua; Ren, Yang; Cui, Lishan

    2015-08-18

    An in-situ nanowire Nb/TiNiCu composite is fabricated based on the concept of strain under-matching between a phase transforming matrix and high strength nanomaterials. The deformation behavior of the Nb nanowire was investigated by means of in-situ synchrotron X-ray diffraction when the TiNiCu matrix underwent different deformation modes. The maximum lattice strain of the Nb nanowires was about 5% when the matrix deformed via martensitic transformation or 1% when deforming plastically by dislocation slip. As a result, the Nb nanowires showed a lattice strain of 3.5% when the matrix deformed in the mixed mode of plastic deformation and martensitic transformation, whichmore » means that the occurrence of plastic deformation does not impede load transfer from the matrix to the nanowires.« less

  15. Microsoft Word - CU-ShEEP Information Exchange Webinar_Venayagamoorthy.docx

    Energy Savers [EERE]

    CSATCourseCatalog_02.doc Microsoft Word - CSATCourseCatalog_02.doc classroom-1008856_960_720.jpg PDF icon Microsoft Word - CSATCourseCatalog_02.doc More Documents & Publications CSAT Course Catalog Headquarters Facilities Master Security Plan - Chapter 17, Headquarters Security Officer Program Headquarters Facilities Master Security Plan - Chapter 8, Operations Security Program

    DE-OE0000660 Page 1 of 3 Project Title: CU-ShEEP Clemson University's Synchrophasor Engineering Education

  16. CU-CTVI-1-B Wholesale Power Rate Schedule | Department of Energy

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

    CTVI-1-B Wholesale Power Rate Schedule CU-CTVI-1-B Wholesale Power Rate Schedule Area: Former customers of TVA System: Cumberland This rate schedule shall be available to customers (hereinafter called the Customer) who are or were formerly in the Tennessee Valley Authority (hereinafter called TVA) service area. This rate schedule shall be applicable to electric capacity and energy generated at the Dale Hollow, Center Hill, Wolf Creek, Old Hickory, Cheatham, Barkley, J. Percy Priest, and Cordell

  17. Production of .sup.64 Cu and other radionuclides using a charged-particle accelerator

    DOE Patents [OSTI]

    Welch, Michael J.; McCarthy, Deborah W.; Shefer, Ruth E.; Klinkowstein, Robert E.

    2000-01-01

    Radionuclides are produced according to the present invention at commercially significant yields and at specific activities which are suitable for use in radiodiagnostic agents such as PET imaging agents and radiotherapeutic agents and/or compositions. In the method and system of the present invention, a solid target having an isotopically enriched target layer electroplated on an inert substrate is positioned in a specially designed target holder and irradiated with a charged-particle beam. The beam is preferably generated using an accelerator such as a biomedical cyclotron at energies ranging from about 5 MeV to about 25 MeV. The target is preferably directly irradiated, without an intervening attenuating foil, and with the charged particle beam impinging an area which substantially matches the target area. The irradiated target is remotely and automatically transferred from the target holder, preferably without transferring any target holder subassemblies, to a conveyance system which is preferably a pneumatic or hydraulic conveyance system, and then further transferred to an automated separation system. The system is effective for processing a single target or a plurality of targets. After separation, the unreacted target material can be recycled for preparation of other targets. In a preferred application of the invention, a biomedical cyclotron has been used to produce over 500 mCi of .sup.64 Cu having a specific activity of over 300 mCi/.mu.g Cu according to the reaction .sup.64 Ni(p,n).sup.64 Cu. These results indicate that accelerator-produced .sup.64 Cu is suitable for radiopharmaceutical diagnostic and therapeutic applications.

  18. Non-uniform Aging on Super Duty Diesel Truck Aged Urea Cu/Zeolite SCR

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

    Catalysts | Department of Energy Cu/Zeolite SCR catalysts aged for 50k miles on a Super Duty diesel truck PDF icon deer10_cheng.pdf More Documents & Publications Deactivation Mechanisms of Base Metal/Zeolite Urea Selective Catalytic Reduction Materials, and Development of Zeolite-Based Hydrocarbon Adsorber Materials Deactivation Mechanisms of Base Metal/Zeolite Urea Selective Catalytic Reduction Materials, and Development of Zeolite-Based Hydrocarbon Adsorber Materials Understanding the

  19. Incorporation of trace elements in Portland cement clinker: Thresholds limits for Cu, Ni, Sn or Zn

    SciTech Connect (OSTI)

    Gineys, N.; Aouad, G.; Sorrentino, F.; Damidot, D.

    2011-11-15

    This paper aims at defining precisely, the threshold limits for several trace elements (Cu, Ni, Sn or Zn) which correspond to the maximum amount that could be incorporated into a standard clinker whilst reaching the limit of solid solution of its four major phases (C{sub 3}S, C{sub 2}S, C{sub 3}A and C{sub 4}AF). These threshold limits were investigated through laboratory synthesised clinkers that were mainly studied by X-ray Diffraction and Scanning Electron Microscopy. The reference clinker was close to a typical Portland clinker (65% C{sub 3}S, 18% C{sub 2}S, 8% C{sub 3}A and 8% C{sub 4}AF). The threshold limits for Cu, Ni, Zn and Sn are quite high with respect to the current contents in clinker and were respectively equal to 0.35, 0.5, 0.7 and 1 wt.%. It appeared that beyond the defined threshold limits, trace elements had different behaviours. Ni was associated with Mg as a magnesium nickel oxide (MgNiO{sub 2}) and Sn reacted with lime to form a calcium stannate (Ca{sub 2}SnO{sub 4}). Cu changed the crystallisation process and affected therefore the formation of C{sub 3}S. Indeed a high content of Cu in clinker led to the decomposition of C{sub 3}S into C{sub 2}S and of free lime. Zn, in turn, affected the formation of C{sub 3}A. Ca{sub 6}Zn{sub 3}Al{sub 4}O{sub 15} was formed whilst a tremendous reduction of C{sub 3}A content was identified. The reactivity of cements made with the clinkers at the threshold limits was followed by calorimetry and compressive strength measurements on cement paste. The results revealed that the doped cements were at least as reactive as the reference cement.

  20. A high temperature diffraction-resistance study of chalcopyrite, CuFeS{sub 2}

    SciTech Connect (OSTI)

    Engin, T.E.; Powell, A.V.; Hull, S.

    2011-08-15

    The electrical, magnetic and structural properties of synthetic chalcopyrite, CuFeS{sub 2}, have been studied up to 873 K using DC resistance measurements performed in-situ during neutron powder diffraction experiments. Under ambient conditions the material adopts the accepted structural model for CuFeS{sub 2} in the space group I4-bar 2d, with the magnetic moment of the Fe{sup 3+} cations aligned along [001]. The electrical resistivity is around 0.3 {Omega} cm under ambient conditions, consistent with semiconductor character, and decreases slightly with increase in temperature until a more abrupt fall occurs in the region 750-800 K. This abrupt change in resistivity is accompanied by a structural transition to a cubic zinc blende structured phase (space group F4-bar 3m) in which Cu{sup +} and Fe{sup 3+} cations are disordered over the same tetrahedral crystallographic sites and by a simultaneous loss of long-range magnetic order. The implications of these results are discussed in the context of previous studies of the chalcopyrite system. - Graphical abstract: Structural, magnetic and electrical properties of CuFeS{sub 2} to 873 K have been investigated using DC resistance measurements, performed in-situ during the collection of powder neutron diffraction data. Highlights: > Structural, magnetic and electronic properties are probed simultaneously. > A fall in resistivity at high temperatures is associated with cation disorder. > The order-disorder transition is accompanied by the loss of magnetic order. > The structural and magnetic phase transition is preceded by a 2-phase region. > Sulphur loss at high temperatures causes the phase transitions to be irreversible.

  1. Pressure-driven orbital reorientations and coordination-sphere reconstructions in [CuF2(H2O)2(pyz)

    SciTech Connect (OSTI)

    Prescimone, A.; Morien, C.; Allan, D.; Schlueter, J.; Tozer, S.; Manson, J. L.; Parsons, S.; Brechin, E. K.; Hill, S.

    2012-07-23

    Successive reorientations of the Jahn-Teller axes associated with the Cu{sup II} ions accompany a series of pronounced structural transitions in the title compound, as is shown by X-ray crystallography and high-frequency EPR measurements. The second transition forces a dimerization involving two thirds of the Cu{sup II} sites due to ejection of one of the water molecules from the coordination sphere

  2. Current Understanding of Cu-Exchanged Chabazite Molecular Sieves for Use as Commercial Diesel Engine DeNOx Catalysts

    SciTech Connect (OSTI)

    Gao, Feng; Kwak, Ja Hun; Szanyi, Janos; Peden, Charles HF

    2013-11-03

    Selective catalytic reduction (SCR) of NOx with ammonia using metal-exchanged molecular sieves with a chabazite (CHA) structure has recently been commercialized on diesel vehicles. One of the commercialized catalysts, i.e., Cu-SSZ-13, has received much attention for both practical and fundamental studies. For the latter, the particularly well-defined structure of this zeolite is allowing long-standing issues of the catalytically active site for SCR in metal-exchanged zeolites to be addressed. In this review, recent progress is summarized with a focus on two areas. First, the technical significance of Cu-SSZ-13 as compared to other Cu-ion exchanged zeolites (e.g., Cu-ZSM-5 and Cu-beta) is highlighted. Specifically, the much enhanced hydrothermal stability for Cu-SSZ-13 compared to other zeolite catalysts is addressed via performance measurements and catalyst characterization using several techniques. The enhanced stability of Cu-SSZ-13 is rationalized in terms of the unique small pore structure of this zeolite catalyst. Second, the fundamentals of the catalytically active center; i.e., the chemical nature and locations within the SSZ-13 framework are presented with an emphasis on understanding structure-function relationships. For the SCR reaction, traditional kinetic studies are complicated by intra-particle diffusion limitations. However, a major side reaction, nonselective ammonia oxidation by oxygen, does not suffer from mass-transfer limitations at relatively low temperatures due to significantly lower reaction rates. This allows structure-function relationships that are rather well understood in terms of Cu ion locations and redox properties. Finally, some aspects of the SCR reaction mechanism are addressed on the basis of in-situ spectroscopic studies.

  3. Microstructure control of Al-Cu films for improved electromigration resistance

    DOE Patents [OSTI]

    Frear, Darrel R.; Michael, Joseph R.; Romig, Jr., Alton D.

    1994-01-01

    A process for the forming of Al-Cu conductive thin films with reduced electromigration failures is useful, for example, in the metallization of integrated circuits. An improved formation process includes the heat treatment or annealing of the thin film conductor at a temperature within the range of from 200.degree. C. to 300.degree. C. for a time period between 10 minutes and 24 hours under a reducing atmosphere such as 15% H.sub.2 in N.sub.2 by volume. Al-Cu thin films annealed in the single phase region of a phase diagram, to temperatures between 200.degree. C. and 300.degree. C. have .theta.-phase Al.sub.2 Cu precipitates at the grain boundaries continuously become enriched in copper, due, it is theorized, to the formation of a thin coating of .theta.-phase precipitate at the grain boundary. Electromigration behavior of the aluminum is, thus, improved because the .theta.-phase precipitates with copper hinder aluminum diffusion along the grain boundaries. Electromigration, then, occurs mainly within the aluminum grains, a much slower process.

  4. High critical currents in heavily doped (Gd,Y)Ba2Cu3Ox superconductor tapes

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Selvamanickam, V.; Gharahcheshmeh, M. Heydari; Xu, A.; Galstyan, E.; Delgado, L.; Cantoni, C.

    2015-01-20

    REBa2Cu3Ox superconductor tapes with moderate levels of dopants have been optimized for high critical current density in low magnetic fields at 77 K, but they do not exhibit exemplary performance in conditions of interest for practical applications, i.e., temperatures less than 50 K and fields of 2–30 T. Heavy doping of REBCO tapes has been avoided by researchers thus far due to deterioration in properties. Here, we report achievement of critical current densities (Jc) above 20 MA/cm2 at 30 K, 3 T in heavily doped (25 mol. % Zr-added) (Gd,Y)Ba2Cu3Ox superconductor tapes, which is more than three times higher thanmore » the Jc typically obtained in moderately doped tapes. Pinning force levels above 1000 GN/m3 have also been attained at 20 K. A composition map of lift factor in Jc (ratio of Jc at 30 K, 3 T to the Jc at 77 K, 0 T) has been developed which reveals the optimum film composition to obtain lift factors above six, which is thrice the typical value. A highly c-axis aligned BaZrO3 (BZO) nanocolumn defect density of nearly 7 × 1011 cm–2 as well as 2–3nm sized particles rich in Cu and Zr have been found in the high Jc films.« less

  5. 110K Bi-Sr-Ca-Cu-O superconductor oxide and method for making same

    DOE Patents [OSTI]

    Veal, B.W.; Downey, J.W.; Lam, D.J.; Paulikas, A.P.

    1992-12-22

    A superconductor is disclosed consisting of a sufficiently pure phase of the oxides of Bi, Sr, Ca, and Cu to exhibit a resistive zero near 110K resulting from the process of forming a mixture of Bi[sub 2]O[sub 3], SrCO[sub 3], CaCO[sub 3] and CuO into a particulate compact wherein the atom ratios are Bi[sub 2], Sr[sub 1.2-2.2], Ca[sub 1.8-2.4], Cu[sub 3]. Thereafter, heating the particulate compact rapidly in the presence of oxygen to an elevated temperature near the melting point of the oxides to form a sintered compact, and then maintaining the sintered compact at the elevated temperature for a prolonged period of time. The sintered compact is cooled and reground. Thereafter, the reground particulate material is compacted and heated in the presence of oxygen to an elevated temperature near the melting point of the oxide and maintained at the elevated temperature for a time sufficient to provide a sufficiently pure phase to exhibit a resistive zero near 110K. 7 figs.

  6. 110K Bi-Sr-Ca-Cu-O superconductor oxide and method for making same

    DOE Patents [OSTI]

    Veal, Boyd W.; Downey, John W.; Lam, Daniel J.; Paulikas, Arvydas P.

    1992-01-01

    A superconductor consisting of a sufficiently pure phase of the oxides of Bi, Sr, Ca, and Cu to exhibit a resistive zero near 110K resulting from the process of forming a mixture of Bi.sub.2 O.sub.3, SrCO.sub.3, CaCO.sub.3 and CuO into aparticulate compact wherein the atom ratios are Bi.sub.2, Sr.sub.1.2-2.2, Ca.sub.1.8-2.4, Cu.sub.3. Thereafter, heating the particulate compact rapidly in the presence of oxygen to an elevated temperature near the melting point of the oxides to form a sintered compact, and then maintaining the sintered compact at the elevated temperature for a prolonged period of time. The sintered compact is cooled and reground. Thereafter, the reground particulate material is compacted and heated in the presence of oxygen to an elevated temperature near the melting point of the oxide and maintained at the elevated temperature for a time sufficient to provide a sufficiently pure phase to exhibit a resistive zero near 110K.

  7. Cooperative Island Growth of Large Area Single-Crystal Graphene by Chemical Vapor Deposition on Cu

    SciTech Connect (OSTI)

    Regmi, Murari [Oak Ridge National Laboratory (ORNL); Rouleau, Christopher [Oak Ridge National Laboratory (ORNL); Puretzky, Alexander A [ORNL; Ivanov, Ilia N [ORNL; Geohegan, David B [ORNL; Chen, Jihua [ORNL; Eastman, Jeffrey [Argonne National Laboratory (ANL); Eres, Gyula [ORNL

    2014-01-01

    We describe a two-step approach for suppressing nucleation of graphene on Cu using chemical vapor deposition. In the first step, as received Cu foils are oxidized in air at temperatures up to 500 C to remove surface impurities and to induce the regrowth of Cu grains during subsequent annealing in H2 flow at 1040 C prior to graphene growth. In the second step, transient reactant cooling is performed by using a brief Ar pulse at the onset of growth to induce collisional deactivation of the carbon growth species. The combination of these two steps results in a three orders of magnitude reduction in the graphene nucleation density, enabling the growth of millimeter-size single crystal graphene grains. A kinetic model shows that suppressing nucleation promotes a cooperative island growth mode that favors the formation of large area single crystal graphene, and it is accompanied by a roughly 3 orders of magnitude increase in the reactive sticking probability of methane compared to that in random nucleation growth.

  8. Microstructure control of Al-Cu films for improved electromigration resistance

    DOE Patents [OSTI]

    Frear, D.R.; Michael, J.R.; Romig, A.D. Jr.

    1994-04-05

    A process for the forming of Al-Cu conductive thin films with reduced electromigration failures is useful, for example, in the metallization of integrated circuits. An improved formation process includes the heat treatment or annealing of the thin film conductor at a temperature within the range of from 200 C to 300 C for a time period between 10 minutes and 24 hours under a reducing atmosphere such as 15% H[sub 2] in N[sub 2] by volume. Al-Cu thin films annealed in the single phase region of a phase diagram, to temperatures between 200 C and 300 C have [theta]-phase Al[sub 2] Cu precipitates at the grain boundaries continuously become enriched in copper, due, it is theorized, to the formation of a thin coating of [theta]-phase precipitate at the grain boundary. Electromigration behavior of the aluminum is, thus, improved because the [theta]-phase precipitates with copper hinder aluminum diffusion along the grain boundaries. Electromigration, then, occurs mainly within the aluminum grains, a much slower process. 5 figures.

  9. Colloidal synthesis and characterization of carbon-supported Pd-Cu nanoparticle oxygen reduction electrocatalysts.

    SciTech Connect (OSTI)

    Kariuki, N. N.; Wang, X.; Mawdsley, J. R.; Ferrandon, M. S.; Niyogi, S. G.; Vaughey, J. T.; Myers, D. J.; Chemical Sciences and Engineering Division

    2010-07-27

    The ability to control the size and composition of metal or alloys nanoparticles is important in preparing catalysts. This paper reports a colloidal synthesis methodology for the preparation of monodisperse palladium-copper (Pd-Cu) alloy nanoparticles with an average diameter of 3 nm for the as-prepared particles and 5-10 nm upon removal of the capping agents. Our approach involves the use of metal precursors, capping agents, and reducing agents in controlled ratios for nanoparticle formation in a single organic phase, followed by deposition of the capped nanoparticles on high surface area carbon and removal of the capping agents via heat treatment in either oxidizing or reducing atmosphere. The results of characterizations using transmission electron microscopy-energy dispersive X-ray analysis (TEM-EDX), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), temperature programmed oxidation and reduction combined with mass spectrometry (TPO/TPR-MS), powder X-ray diffraction (XRD), and cyclic voltammetry (CV) are discussed. The resulting high-surface-area-carbon-supported Pd-Cu catalysts (PdCu/C) showed high activity for the oxygen reduction reaction (ORR) in acidic electrolyte. Our study revealed composition and heat-treatment dependent ORR activity.

  10. Electronic structure, irreversibility line and magnetoresistance of Cu0.3Bi2Se3 superconductor

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Hemian, Yi; Gu, Genda; Chen, Chao -Yu; Sun, Xuan; Xie, Zhuo -Jin; Feng, Ya; Liang, Ai -Ji; Peng, Ying -Ying; He, Shao -Long; Zhao, Lin; et al

    2015-06-01

    CuxBi2Se3 is a superconductor that is a potential candidate for topological superconductors. We report our laser-based angle-resolved photoemission measurement on the electronic structure of the CuxBi2Se3 superconductor, and a detailed magneto-resistance measurement in both normal and superconducting states. We find that the topological surface state of the pristine Bi2Se3 topological insulator remains robust after the Cu-intercalation, while the Dirac cone location moves downward due to electron doping. Detailed measurements on the magnetic field-dependence of the resistance in the superconducting state establishes an irreversibility line and gives a value of the upper critical field at zero temperature of ~4000 Oe formore » the Cu0.3Bi2Se3 superconductor with a middle point Tc of 1.9K. The relation between the upper critical field Hc2 and temperature T is different from the usual scaling relation found in cuprates and in other kinds of superconductors. Small positive magneto-resistance is observed in Cu0.3Bi2Se3 superconductors up to room temperature. As a result, these observations provide useful information for further study of this possible candidate for topological superconductors.« less

  11. Surface and grain boundary scattering in nanometric Cu thin films: A quantitative analysis including twin boundaries

    SciTech Connect (OSTI)

    Barmak, Katayun [Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027 and Department of Materials Science and Engineering and Materials Research Science and Engineering Center, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213 (United States); Darbal, Amith [Department of Materials Science and Engineering and Materials Research Science and Engineering Center, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213 (United States); Ganesh, Kameswaran J.; Ferreira, Paulo J. [Materials Science and Engineering, The University of Texas at Austin, 1 University Station, Austin, Texas 78712 (United States); Rickman, Jeffrey M. [Department of Materials Science and Engineering and Department of Physics, Lehigh University, Bethlehem, Pennsylvania 18015 (United States); Sun, Tik; Yao, Bo; Warren, Andrew P.; Coffey, Kevin R., E-mail: kb2612@columbia.edu [Department of Materials Science and Engineering, University of Central Florida, 4000 Central Florida Boulevard, Orlando, Florida 32816 (United States)

    2014-11-01

    The relative contributions of various defects to the measured resistivity in nanocrystalline Cu were investigated, including a quantitative account of twin-boundary scattering. It has been difficult to quantitatively assess the impact twin boundary scattering has on the classical size effect of electrical resistivity, due to limitations in characterizing twin boundaries in nanocrystalline Cu. In this study, crystal orientation maps of nanocrystalline Cu films were obtained via precession-assisted electron diffraction in the transmission electron microscope. These orientation images were used to characterize grain boundaries and to measure the average grain size of a microstructure, with and without considering twin boundaries. The results of these studies indicate that the contribution from grain-boundary scattering is the dominant factor (as compared to surface scattering) leading to enhanced resistivity. The resistivity data can be well-described by the combined FuchsSondheimer surface scattering model and MayadasShatzkes grain-boundary scattering model using Matthiessen's rule with a surface specularity coefficient of p?=?0.48 and a grain-boundary reflection coefficient of R?=?0.26.

  12. Comparative Density Functional Study of Methanol Decomposition on Cu4 and Co4 Clusters

    SciTech Connect (OSTI)

    Mehmood, Faisal; Greeley, Jeffrey P.; Zapol, Peter; Curtiss, Larry A.

    2010-11-18

    A density functional theory study of the decomposition of methanol on Cu4 and Co4 clusters is presented. The reaction intermediates and activation barriers have been determined for reaction steps to form H2 and CO. For both clusters, methanol decomposition initiated by C-H and O-H bond breaking was investigated. In the case of a Cu4 cluster, methanol dehydrogenation through hydroxymethyl (CH2OH), hydroxymethylene (CHOH), formyl (CHO), and carbon monoxide (CO) is found to be slightly more favorable. For a Co4 cluster, the dehydrogenation pathway through methoxy (CH3O) and formaldehyde (CH2O) is slightly more favorable. Each of these pathways results in formation of CO and H2. The Co cluster pathway is very favorable thermodynamically and kinetically for dehydrogenation. However, since CO binds strongly, it is likely to poison methanol decomposition to H2 and CO at low temperatures. In contrast, for the Cu cluster, CO poisoning is not likely to be a problem since it does not bind strongly, but the dehydrogenation steps are not energetically favorable. Pathways involving C-O bond cleavage are even less energetically favorable. The results are compared to our previous study of methanol decomposition on Pd4 and Pd8 clusters. Finally, all reaction energy changes and transition state energies, including those for the Pd clusters, are related in a linear, Broensted-Evans-Polanyi plot.

  13. Enhancement of spin-Seebeck effect by inserting ultra-thin Fe{sub 70}Cu{sub 30} interlayer

    SciTech Connect (OSTI)

    Kikuchi, D.; Ishida, M.; Murakami, T.; Uchida, K.; Qiu, Z.; Saitoh, E.

    2015-02-23

    We report the longitudinal spin-Seebeck effects (LSSEs) for Pt/Fe{sub 70}Cu{sub 30}/BiY{sub 2}Fe{sub 5}O{sub 12} (BiYIG) and Pt/BiYIG devices. The LSSE voltage was found to be enhanced by inserting an ultra-thin Fe{sub 70}Cu{sub 30} interlayer. This enhancement decays sharply with increasing the Fe{sub 70}Cu{sub 30} thickness, suggesting that it is not due to bulk phenomena, such as a superposition of conventional thermoelectric effects, but due to interface effects related to the Fe{sub 70}Cu{sub 30} interlayer. Combined with control experiments using Pt/Fe{sub 70}Cu{sub 30} devices, we conclude that the enhancement of the LSSE voltage in the Pt/Fe{sub 70}Cu{sub 30}/BiYIG devices is attributed to the improvement of the spin-mixing conductance at the Pt/BiYIG interfaces.

  14. Bacteriostatic and anti-collagenolytic dental materials through the incorporation of polyacrylic acid modified CuI nanoparticles

    DOE Patents [OSTI]

    Renne, Walter George; Mennito, Anthony Samuel; Schmidt, Michael Gerard; Vuthiganon, Jompobe; Chumanov, George

    2015-05-19

    Provided are antibacterial and antimicrobial surface coatings and dental materials by utilizing the antimicrobial properties of copper chalcogenide and/or copper halide (CuQ, where Q=chalcogens including oxygen, or halogens, or nothing). An antimicrobial barrier is created by incorporation of CuQ nanoparticles of an appropriate size and at a concentration necessary and sufficient to create a unique bioelectrical environment. The unique bioelectrical environment results in biocidal effectiveness through a multi-factorial mechanism comprising a combination of the intrinsic quantum flux of copper (Cu.sup.0, Cu.sup.1+, Cu.sup.2+) ions and the high surface-to-volume electron sink facilitated by the nanoparticle. The result is the constant quantum flux of copper which manifests and establishes the antimicrobial environment preventing or inhibiting the growth of bacteria. The presence of CuQ results in inhibiting or delaying bacterial destruction and endogenous enzymatic breakdown of the zone of resin inter-diffusion, the integrity of which is essential for dental restoration longevity.

  15. An In-Situ XAS Study of the Structural Changes in a CuO-CeO2/Al2O3 Catalyst during Total Oxidation of Propane

    SciTech Connect (OSTI)

    Silversmith, Geert; Poelman, Hilde; Poelman, Dirk; Gryse, Roger de; Olea, Maria; Balcaen, Veerle; Heynderickx, Philippe; Marin, Guy B.

    2007-02-02

    A CuOx-CeOx/Al2O3 catalyst was studied with in-situ transmission Cu K XAS for the total oxidation of propane as model reaction for the catalytic elimination of volatile organic compounds. The local Cu structure was determined for the catalyst as such, after pre-oxidation and after reduction with propane. The catalyst as such has a local CuO structure. No structural effect was observed upon heating in He up to 600 deg. C or after pre-oxidation at 150 deg. C. A full reduction of the Cu2+ towards metallic Cu0 occurred, when propane was fed to the catalyst. The change in local Cu structure during propane reduction was followed with a time resolution of 1 min. The {chi}(k) scans appeared as linear combinations of start and end spectra, CuO and Cu structure, respectively. However, careful examination of the XANES edge spectra indicates the presence of a small amount of additional Cu1+ species.

  16. Copper doping of ZnO crystals by transmutation of {sup 64}Zn to {sup 65}Cu: An electron paramagnetic resonance and gamma spectroscopy study

    SciTech Connect (OSTI)

    Recker, M. C.; McClory, J. W. Holston, M. S.; Golden, E. M.; Giles, N. C.; Halliburton, L. E.

    2014-06-28

    Transmutation of {sup 64}Zn to {sup 65}Cu has been observed in a ZnO crystal irradiated with neutrons. The crystal was characterized with electron paramagnetic resonance (EPR) before and after the irradiation and with gamma spectroscopy after the irradiation. Major features in the gamma spectrum of the neutron-irradiated crystal included the primary 1115.5 keV gamma ray from the {sup 65}Zn decay and the positron annihilation peak at 511 keV. Their presence confirmed the successful transmutation of {sup 64}Zn nuclei to {sup 65}Cu. Additional direct evidence for transmutation was obtained from the EPR of Cu{sup 2+} ions (where {sup 63}Cu and {sup 65}Cu hyperfine lines are easily resolved). A spectrum from isolated Cu{sup 2+} (3d{sup 9}) ions acquired after the neutron irradiation showed only hyperfine lines from {sup 65}Cu nuclei. The absence of {sup 63}Cu lines in this Cu{sup 2+} spectrum left no doubt that the observed {sup 65}Cu signals were due to transmuted {sup 65}Cu nuclei created as a result of the neutron irradiation. Small concentrations of copper, in the form of Cu{sup +}-H complexes, were inadvertently present in our as-grown ZnO crystal. These Cu{sup +}-H complexes are not affected by the neutron irradiation, but they dissociate when a crystal is heated to 900 °C. This behavior allowed EPR to distinguish between the copper initially in the crystal and the copper subsequently produced by the neutron irradiation. In addition to transmutation, a second major effect of the neutron irradiation was the formation of zinc and oxygen vacancies by displacement. These vacancies were observed with EPR.

  17. The effect of Cu/Zn molar ratio on CO{sub 2} hydrogenation over Cu/ZnO/ZrO{sub 2}/Al{sub 2}O{sub 3} catalyst

    SciTech Connect (OSTI)

    Shaharun, Salina E-mail: maizats@petronas.com.my; Shaharun, Maizatul S. E-mail: maizats@petronas.com.my; Taha, Mohd F.; Mohamad, Dasmawati

    2014-10-24

    Catalytic hydrogenation of carbon dioxide (CO{sub 2}) to methanol is an attractive way to recycle and utilize CO{sub 2}. A series of Cu/ZnO/Al{sub 2}O{sub 3}/ZrO{sub 2} catalysts (CZAZ) containing different molar ratios of Cu/Zn were prepared by the co-precipitation method and investigated in a stirred slurry autoclave system. The catalysts were characterized by temperature-programmed reduction (TPR), field emission scanning electron microscopy-energy dispersive analysis (FESEM-EDX), X-ray diffraction (XRD) and N{sub 2} adsorption-desorption. Higher surface area, SA{sub BET} values (42.659.9 m{sup 2}/g) are recorded at low (1) and high (5) Cu/Zn ratios with the minimum value of 35.71 m{sup 2}/g found for a Cu/Zn of 3. The reducibility of the metal oxides formed after calcination of catalyst samples was also affected due to change in metal-support interaction. At a low reaction temperature of 443 K, total gas pressure of 3.0 MPa and 0.1 g/mL of the CZAZ catalyst, the selectivity to methanol decreased as the Cu/Zn molar ratio increased, and the maximum selectivity of 67.73 was achieved at Cu/Zn molar ratio of 1. With a reaction time of 3h, the best performing catalyst was CZAZ75 with Cu/Zn molar ratio of 5 giving methanol yield of 79.30%.

  18. Manufacturable CuIn(Ga)Se{sub 2}-based solar cells via development of co-sputtered CuInSe{sub 2} absorber layers

    SciTech Connect (OSTI)

    Dr. Ingrid Eisgruber

    1999-03-20

    Yield and reproducibility remain issues in CuIn(Ga)Se{sub 2} (CIGS) photovoltaic module fabrication. While small-area cells (<1 cm{sup 2}) over 18% efficient have been reported, the best large-area manufactured devices (>1 ft{sup 2}) are 11% efficient with about 60% yield. If improvements in large-area manufacturing can accomplish 15% efficiency and 90% yield, the result is a doubling in throughput leading to a reduction in cost per watt of over 50%. The challenge now facing the photovoltaics industry is to bring the efficiencies of small-area cells and large-area industrial modules closer together and to raise manufacturing yields.

  19. Synthesis and Evaluation of Cu-SAPO-34 Catalysts for Ammonia Selective Catalytic Reduction. 1. Aqueous Solution Ion Exchange

    SciTech Connect (OSTI)

    Gao, Feng; Walter, Eric D.; Washton, Nancy M.; Szanyi, Janos; Peden, Charles HF

    2013-09-06

    SAPO-34 molecular sieves are synthesized using various structure directing agents (SDAs). Cu-SAPO-34 catalysts are prepared via aqueous solution ion exchange. Catalysts are characterized with surface area/pore volume measurements, temperature programmed reduction (TPR), electron paramagnetic resonance (EPR) and nuclear magnetic resonance (NMR) spectroscopies. Catalytic properties are examined using standard ammonia selective catalytic reduction (NH3-SCR) and ammonia oxidation reactions. During solution ion exchange, different SAPO-34 samples undergo different extent of structural damage via irreversible hydrolysis. Si content within the samples (i.e., Al-O-Si bond density) and framework stress are key factors that affect irreversible hydrolysis. Even using very dilute Cu acetate solutions, it is not possible to generate Cu-SAPO-34 samples with only isolated Cu2+ ions. Small amounts of CuOx species always coexist with isolated Cu2+ ions. Highly active and selective Cu-SAPO-34 catalysts for NH3-SCR are readily generated using this synthesis protocol, even for SAPO-34 samples that degrade substantially during solution ion exchange. High-temperature aging is found to improve the catalytic performance. This is likely due to reduction of intracrystalline mass-transfer limitations via formation of additional porosity in the highly defective SAPO-34 particles formed after ion exchange. The authors gratefully acknowledge the US Department of Energy (DOE), Office of Energy Efficiency and Renewable Energy, Office of Vehicle Technologies for the support of this work. The research described in this paper was performed at the Environmental Molecular Sciences Laboratory (EMSL), a national scientific user facility sponsored by the DOEs Office of Biological and Environmental Research and located at Pacific Northwest National Laboratory (PNNL). PNNL is operated for the US DOE by Battelle Memorial Institute under contract number DE-AC05-76RL01830.

  20. Electron scattering mechanisms in Cu-Mn films for interconnect applications

    SciTech Connect (OSTI)

    Misjk, F.; Nagy, K. H.; Radnczi, G.; Lobotka, P.

    2014-08-28

    Electrical properties and corresponding structural features of Cu-Mn alloy films with potential application as barrier and interconnect layers were studied. Cu-Mn films were deposited by DC magnetron sputtering at room temperature on SiO{sub 2} substrates. Electrical resistivity measurements were made as a function of film composition and temperature. The specific resistivity varies linearly with the Mn content showing a maximum of 205???cm at 80 at. % Mn. The temperature coefficient of resistance (TCR) of all alloy films is low, showing non-metallic conductivity for most compositions. Also a minimum TCR has been observed in the 4080 at. % Mn range which was attributed to a magnetic transformation around 200300?K. Electrical resistivity measurements are correlated with the film structure revealed by transmission electron microscopy to clarify the phase regions throughout the composition range. In the 2040 at. % and 7080 at. % Mn ranges, two-phase structures were identified, where Cu- or Mn-rich solid solution grains were surrounded by a thin amorphous covering layer. Based on the revealed phase regions and morphologies electron scattering mechanisms in the system were evaluated by combining the Matthiessen's rule and the Mayadas-Schatzkes theory. Grain boundary reflectivity coefficients (r?=?0.60.8) were calculated from fitting the model to the measurements. The proposed model indicates that, in a binary system, the special arrangement of the two phases results in new scattering mechanisms. The results are of value in optimizing the various parameters needed to produce a suitable barrier layer.

  1. Shape memory properties and microstructural evolution of rapidly solidified CuAlBe alloys

    SciTech Connect (OSTI)

    Ergen, Semra; Uzun, Orhan; Yilmaz, Fikret; Kiliaslan, M. Fatih

    2013-06-15

    In this work, the effects of Be addition on the microstructure and phase transformation temperatures of Cu12AlxBe (x = 0.4, 0.5 and 0.6 wt.%) shape memory alloys fabricated by using the arc-melting and melt-spinning techniques have been investigated. X-ray diffraction analysis revealed that the arc-melted alloys consisted of austenitic ?{sub 1}, martensitic ?{sub 1}? and ?{sub 2} precipitate phases, whereas melt-spun ribbons were composed of a fully martensitic phase. The average grain size of martensitic phases in melt-spun ribbons was determined by electron microscopy images, showing a decrease with increasing Beryllium (Be) amount. Moreover, it was found that the Be addition in the arc-melted alloys had a distinct effect on the morphology of the ?{sub 2} precipitate phase. Transmission electron microscopy analysis showed that the thickness of martensitic plates in the melt-spun ribbons reduced with increasing Be addition. In a differential scanning calorimeter analysis, no martensitic transformation (M{sub s}) peak was observed in arc-melted alloys, but it was clearly detected in melt-spun ribbons, in which M{sub s} decreased dramatically with increasing Be addition. The improvement in the shape memory ability of melt-spun ribbons was explained in terms of the refinement in grain size and martensitic plates. - Highlights: The CuAlBe SMAs were produced by means of arc-melter and melt-spinner techniques. MT was directly obtained in melt-spuns without any intermediate process. The transformation temperatures decreased with increasing Be amount. The thickness of martensitic plates in the ribbons reduced with increasing Be. SMP of CuAl was improved by the addition of Be together with rapid solidification.

  2. X-ray-absorption study of CuBr at high pressure

    SciTech Connect (OSTI)

    Tranquada, J.M.; Ingalls, R.

    1986-09-15

    The x-ray-absorption spectrum of cuprous bromide has been measured as a function of pressure. The x-ray-absorption near-edge structure proved to be an excellent indicator of high-pressure phase transitions in this material. The normalized ''white-line'' peak heights at both the Cu and Br K-italic edges decreased on entering the tetragonal phase and increased in going to the NaCl structure. The zinc-blende to tetragonal phase transition took place over a very narrow pressure range centered at 46 +- 5 kbar. The transformation from the tetragonal to the NaCl structure, on the other hand, showed a broad mixed-phase region, suggesting a nucleation-and-growth mechanism for the transition. The mixed-phase region was centered at 75 +- 6 kbar. No evidence of a phase between the zinc-blende and tetragonal phases was observed, presumably because it does not exist. Analysis of the extended x-ray-absorption fine-structure (EXAFS) clearly showed that there is no change in coordination in going from the zinc-blende to the tetragonal phase although the nearest-neighbor distance increases slightly. A much larger increase in R-italic/sub 1/ occurs at the transition to the NaCl structure, where the coordination increases from 4 to 6. The mean-square deviation in the nearest-neighbor bond length, sigma/sub 1//sup 2/, appears to be a fairly smooth function of nearest-neighbor distance, decreasing (or increasing) as R-italic/sub 1/ decreases (or increases) more or less independent of structure. Evidence from the literature was presented to suggest that the zinc-blende to tetragonal transition in CuBr (and also CuCl) should occur by shear deformation.

  3. Magnetic order in RBa/sub 2/Cu/sub 2/O/sub 6+//sub x/ (invited)

    SciTech Connect (OSTI)

    Lynn, J.W.; Li, W.

    1988-11-15

    Neutron scattering results on the RBa/sub 2/ Cu/sub 3/ O/sub 6+//sub x/ (R = rare earth) class of systems are reviewed. For the oxygen-deficient systems (x<0.5), which are semiconducting, the Cu ions are observed to order with Neel temperatures as high as 500 K. The magnetic structure consists of strong nearest-neighbor antiferromagnetic couplings of the Cu spins within the Cu-O/sub 2/ layers, while nearest-neighbor spins in adjacent layers are also aligned antiferromagnetically. The moments are constrained in the tetragonal plane. At lower temperatures the Cu moments in the oxygen-deficient ''chain'' layers also order antiferromagnetically, with a moment that can be quite substantial (approx. 1/2 ..mu../sub B/). Both transition temperatures are very sensitive to the oxygen concentration. The magnetic heavy rare-earth compounds, on the other hand, order antiferromagnetically at very low temperatures, analogous to the ''conventional'' magnetic-superconductor systems such as RMo/sub 6/ S/sub 8/ and RRh/sub 4/ B/sub 4/. The ordering is not very sensitive to the oxygen concentration, and the antiferromagnetic state coexists with superconductivity. Differences in the ordering behavior are ascribed to crystal-field effects, which are briefly discussed. Finally, small-angle neutron scattering results in the vicinity of the superconducting transition temperature are also discussed.

  4. Shape controlled synthesis of Cu{sub 2}O and its catalytic application to synthesize amorphous carbon nanofibers

    SciTech Connect (OSTI)

    Du Fanglin Liu Jungang; Guo Zhiyan

    2009-01-08

    Octahedral Cu{sub 2}O particles and Cu{sub 2}O nanowires were synthesized by a simple solution-phase route using N{sub 2}H{sub 4}.H{sub 2}O as reducing agent at room temperature. Amorphous carbon nanofibers were synthesized using octahedral Cu{sub 2}O particles and an acetylene gas source at atmospheric pressure. The samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy and thermogravimetric (TG) analysis. SEM and TEM images indicated that most of the obtained octahedral Cu{sub 2}O particles had an edge length of 400-700 nm. The obtained nanowires had uniform diameters of about 15 nm, and the length of the nanowires ranged from 5 to 10 {mu}m. The XRD result revealed the amorphous feature of the nanofibers. IR spectrum revealed that the nanofibers consist of -CH, -CH{sub 2,} -C=C- and -CH{sub 3} groups. The concentrations of N{sub 2}H{sub 4}.H{sub 2}O and NaOH played important roles in controlling the geometric shape of the Cu{sub 2}O.

  5. Impact of sulfation and desulfation on NOx reduction using Cu-chabazite SCR catalysts

    SciTech Connect (OSTI)

    Brookshear, Daniel William; Nam, Jeong -Gil; Nguyen, Ke; Toops, Todd J.; Binder, Andrew J.

    2015-06-05

    This bench reactor study investigates the impact of gaseous sulfur on the NOx reduction activity of Cu-chabazite SCR (Cu-CHA) catalysts at SO2 concentrations representative of marine diesel engine exhaust. After two hours of 500 ppm SO2 exposure at 250 and 400 °C in the simulated diesel exhaust gases, the NOx reduction activity of the sulfated Cu-CHA SCR catalysts is severely degraded at evaluation temperatures below 250 °C; however, above 250 °C the impact of sulfur exposure is minimal. EPMA shows that sulfur is located throughout the washcoat and along the entire length of the sulfated samples. Interestingly, BET measurements reveal that the sulfated samples have a 20% decrease in surface area. Moreover, the sulfated samples show a decrease in NOx/nitrate absorption during NO exposure in a DRIFTS reactor which suggests that Cu sites in the catalyst are blocked by the presence of sulfur. SO2 exposure also results in an increase in NH3 storage capacity, possibly due to the formation of ammonium sulfate species in the sulfated samples. In all cases, lean thermal treatments as low as 500 °C reverse the effects of sulfur exposure and restore the NOx reduction activity of the Cu-CHA catalyst to that of the fresh condition.

  6. Nanostructured Cu-Cr alloy with high strength and electrical conductivity

    SciTech Connect (OSTI)

    Islamgaliev, R. K. Nesterov, K. M.; Bourgon, J.; Champion, Y.; Valiev, R. Z.

    2014-05-21

    The influence of nanostructuring by high pressure torsion (HPT) on strength and electrical conductivity in the Cu-Cr alloy has been investigated. Microstructure of HPT samples was studied by transmission electron microscopy with special attention on precipitation of small chromium particles after various treatments. Effect of dynamic precipitation leading to enhancement of strength and electrical conductivity was observed. It is shown that nanostructuring leads to combination of high ultimate tensile strength of 790–840 MPa, enhanced electrical conductivity of 81%–85% IACS and thermal stability up to 500 °C. The contributions of grain refinement and precipitation to enhanced properties of nanostructured alloy are discussed.

  7. La2-xSrxCuO4 superconductor nanowire devices

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Litombe, N. E.; Bollinger, A. T.; Hoffman, J. E.; Božović, I.

    2014-07-02

    La2-xSrxCuO₄ nanowire devices have been fabricated and characterized using electrical transport measurements. In addition, nanowires with widths down to 80 nm are patterned using high-resolution electron beam lithography. However, the narrowest nanowires show incomplete superconducting transitions with some residual resistance at T = 4 K. Here, we report on refinement of the fabrication process to achieve narrower nanowire devices with complete superconducting transitions, opening the path to the study of novel physics arising from dimension-limited superconductivity on the nanoscale.

  8. Flux pinning by precipitates in the Bi-Sr-Ca-Cu-O system

    DOE Patents [OSTI]

    Shi, Donglu

    1992-01-01

    A fundamental pinning mechanism has been identified in the Bi-Sr-Ca-Cu-O system. The pinning strength has been greatly increased by the introduction of calcium- and copper-rich precipitates into the sample matrix. The calcium and copper are supersaturated in the system by complete melting, and the fine calcium and copper particles precipitated during subsequent crystallization anneal to obtain the superconducting phases. The intragrain critical current density has been increased from the order of 10.sup.5 A/cm.sup.2 to 10.sup.7 A/cm.sup.2 at 5 T.

  9. La??xSrxCuO? superconductor nanowire devices

    SciTech Connect (OSTI)

    Litombe, N. E.; Bollinger, A. T.; Hoffman, J. E.; Bozovic, I.

    2014-07-02

    La??xSrxCuO? nanowire devices have been fabricated and characterized using electrical transport measurements. Nanowires with widths down to 80 nm are patterned using high-resolution electron beam lithography. However, the narrowest nanowires show incomplete superconducting transitions with some residual resistance at T = 4 K. Here, we report on refinement of the fabrication process to achieve narrower nanowire devices with complete superconducting transitions, opening the path to the study of novel physics arising from dimension-limited superconductivity on the nanoscale.

  10. Shell Model Description of the Odd-Odd Co and Cu Nuclei

    SciTech Connect (OSTI)

    Medina, N. H.; Allegro, P. R. P.; Oliveira, J. R. B. de; Ribas, R. V.; Seale, W. A.; Toufen, D. L.; Silveira, M. A. G.

    2007-10-26

    The known excited states of the odd-odd nuclei {sup 54,56,58,60}Co and 60,62,64,66Cu were interpreted in the framework of the large scale shell model (LSSM), using several effective interactions and configuration spaces. For the description of the negative parity states, we have allowed one particle excitation to the g{sub 9/2} orbital. The LSSM using the GXPF1 effective interaction reproduces well the first excited states in all of these nuclei.

  11. Bi-Sr-Ca-Cu-O surface studied by means of scanning tunnelling microscope

    SciTech Connect (OSTI)

    Witek, A.; Dabkowski, A.; Rauluszkiewicz, J.

    1989-03-10

    Surface topography of the high-T/sub c/ superconductor BiSrCaCu/sub 2/O/sub x/ has been investigated by means of scanning tunnelling microscope. The measurements were performed on the natural surface of ceramics material in air at room temperature. It can be deduced from the surface images, that bulk orthorhombic crystal structure extends to the surface. The surface seems to be uniform metallic in character and not drastically contaminated. Regular steps observed on the surface correspond to the dimension of the unit cell in z direction or its multiples.

  12. Surface relief produced by diffusion induced boundary migration in Cu-Zn

    SciTech Connect (OSTI)

    Tsai, Y.S.; Meyrick, G.; Shewmon, P.G.

    1984-03-01

    Experimental observations are presented that demonstrate that diffusion induced grain boundary migration in copper foils exposed to zinc vapor, from a Cu-15 pct Zn alloy, can be studied directl after treatment without etching. The general characteristics of migration are in accord with previous investigations, but novel changes in the surface topography are described. Pits were formed on the surface of areas swept by boundary migration; also, the surface was often converted into a series of corrugations. The formation of pits suggests that the grain boundary diffusivity of zinc exceeds that of copper. The corrugations are believed to indicate that boundaries sometimes move in an intermittent manner.

  13. ScanningTunneling Luminescence of Grain Boundaries in Cu(In,Ga)Se2

    SciTech Connect (OSTI)

    Romero, M. J.; Jiang, C.-S.; Al-Jassim, M. M.; Noufi, R.

    2005-01-01

    At the Laboratory, photon emission in semiconductors has been mapped in the nanoscale using scanning tunneling microscopy (STM). In this Solar Program Review Meeting, we report on the latest results obtained in Cu(In,Ga)Se2 (CIGS) thin films by this adapted STM. Scanning tunneling luminescence (STL) spectroscopy suggests that photons are emitted near the surface of CIGS. STL is excited either by (1) diffusion of tunneling electrons and subsequent recombination with available holes in CIGS or (2) impact ionization by hot electrons. Which process becomes predominant depends on the voltage applied to the STM tip. Photon mapping shows electronically active, extended defects near the surface of CIGS thin films.

  14. ESR of Gd{sup 3+} in the Kondo-lattice compound YbAgCu{sub 4} and its reference compounds RAgCu{sub 4} (R=Y,Lu)

    SciTech Connect (OSTI)

    Pagliuso, P.G.; Rettori, C.; Oseroff, S.B.; Sarrao, J.; Fisk, Z.; Cornelius, A.; Hundley, M.F.

    1997-10-01

    Low-temperature (T{lt}30thinspK) electron-spin-resonance (ESR) experiments of Gd{sup 3+} diluted in the Kondo-lattice compound YbAgCu{sub 4} and its reference compounds YAgCu{sub 4} and LuAgCu{sub 4} are interpreted in terms of an enhanced density of states at the Fermi level for the Yb-based compound. The results of susceptibility and ESR (Korringa rate and g-shift) measurements show negligible electron-electron exchange enhancement for all the studied compounds. The exchange interaction between the Gd{sup 3+} local moment and the conduction electrons (c-e) is c-e wave vector dependent in all three compounds. {copyright} {ital 1997} {ital The American Physical Society}

  15. Optical properties of La{sub 2}CuO{sub 4} and La{sub 2-x}Ca{sub x}CuO{sub 4} crystallites in UV-vis-NIR region synthesized by sol-gel process

    SciTech Connect (OSTI)

    Li Yifeng; Huang Jianfeng Cao Liyun; Wu Jianpeng; Fei Jie

    2012-02-15

    La{sub 2}CuO{sub 4} and La{sub 2-x}Ca{sub x}CuO{sub 4} crystallites were prepared via a simple sol-gel process. The as-prepared La{sub 2}CuO{sub 4} and La{sub 2} {sub -x}Ca{sub x}CuO{sub 4} crystallites were characterized by X-ray diffraction, transmission electron microscope and UV-vis-NIR spectra. Results show that the grain size of La{sub 2}CuO{sub 4} crystallites increases with the increase of heat treatment temperature from 600 Degree-Sign C to 800 Degree-Sign C. Optical properties show that La{sub 2}CuO{sub 4} crystallites have broad absorption both in the UV-vis region and in the NIR region. The band gap of the as-prepared crystallites decreases from 1.367 eV to 1.284 eV with the increase of calcination temperature from 600 Degree-Sign C to 800 Degree-Sign C. In the series of La{sub 2-x}Ca{sub x}CuO{sub 4} compounds (x = 0.05, 0.08, 0.10, 0.12, 0.15 and 0.20), all of the samples exhibit an orthogonal crystal structure and the solubility limit of Ca{sup 2+} in La{sub 2}CuO{sub 4} is within the range of x = 0.12-0.15. In the whole UV-vis-NIR region, La{sub 2-x}Ca{sub x}CuO{sub 4} crystallites exhibit a broad absorption and the corresponding band gap first increases and then decreases with increasing of Ca{sup 2+} content. - Highlights: Black-Right-Pointing-Pointer The optical band gap can be tuned by adjusting the grain size and Ca{sup 2+} content. Black-Right-Pointing-Pointer La{sub 2}CuO{sub 4} crystallites exhibit a broad absorption band both in the UV-vis region and in the NIR region. Black-Right-Pointing-Pointer The band gap increases from 1.284 eV to 1.319 eV with the decrease of heat treatment temperature. Black-Right-Pointing-Pointer In the whole UV-vis-NIR region, the La{sub 2-x}Ca{sub x}CuO{sub 4} crystallites displayed a broad absorption. Black-Right-Pointing-Pointer The band gap of La{sub 2-x}Ca{sub x}CuO{sub 4} increases linearly with doping level when 0 {<=} x {<=} 0.12.

  16. System size dependence of cluster properties from two-particle angular correlations in Cu+Cu and Au+Au collisions at sq root(s{sub NN})=200 GeV

    SciTech Connect (OSTI)

    Alver, B.; Ballintijn, M.; Busza, W.; Gulbrandsen, K.; Henderson, C.; Kane, J. L.; Kulinich, P.; Li, W.; Loizides, C.; Reed, C.; Roland, C.; Roland, G.; Stephans, G. S. F.; Nieuwenhuizen, G. J. van; Vaurynovich, S. S.; Verdier, R.; Veres, G. I.; Wenger, E.; Wyslouch, B.; Back, B. B.

    2010-02-15

    We present results on two-particle angular correlations in Cu+Cu and Au+Au collisions at a center-of-mass energy per nucleon pair of 200 GeV over a broad range of pseudorapidity (eta) and azimuthal angle (phi) values as a function of collision centrality. The PHOBOS detector at the Relativistic Heavy Ion Collider has a uniquely large angular coverage for inclusive charged particles, which allows for the study of correlations on both long- and short-range scales. A complex two-dimensional correlation structure in {Delta}{eta} and {Delta}{phi} emerges, which is interpreted in the context of a cluster model. The effective cluster size and decay width are extracted from the two-particle pseudorapidity correlation functions. The effective cluster size found in semicentral Cu+Cu and Au+Au collisions is comparable to that found in proton-proton collisions but a nontrivial decrease in size with increasing centrality is observed. Moreover, a comparison of results from Cu+Cu versus Au+Au collisions shows an interesting scaling of the effective cluster size with the measured fraction of total cross section (which is related to the ratio of the impact parameter to the nuclear radius, b/2R), suggesting a geometric origin. Further analysis for pairs from restricted azimuthal regions shows that the effective cluster size at {Delta}{phi}{approx}180 deg. drops more rapidly toward central collisions than the size at {Delta}{phi}{approx}0 deg. The effect of limited {eta} acceptance on the cluster parameters is also addressed, and a correction is applied to present cluster parameters for full {eta} coverage, leading to much larger effective cluster sizes and widths than previously noted in the literature. These results should provide insight into the hot and dense medium created in heavy ion collisions.

  17. Measurement of K0S and K*0 in p+p, d+Au, and Cu+Cu collisions at sqrt SNN = 200 GeV

    SciTech Connect (OSTI)

    Adare, A.; Aidala, C.

    2014-11-01

    The PHENIX experiment at the Relativistic Heavy Ion Collider has performed a systematic study of K0S and K*0 meson production at midrapidity in p+p, d+Au, and Cu+Cu collisions at sqrt SNN = 200 GeV. The K0S and K*0 mesons are reconstructed via their K0S and ?0(???)?0 (???) and K*0 ? K #25;? decay modes, respectively. The measured transverse-momentum spectra are used to determine the nuclear modification factor of K0S and K*0 mesons in d+Au and Cu+Cu collisions at different centralities. In the d+Au collisions, the nuclear modification factor of K0S and K*0 mesons is almost constant as a function of transverse momentum and is consistent with unity showing that cold-nuclear-matter effects do not play a significant role in the measured kinematic range. In Cu+Cu collisions, within the uncertainties no nuclear modification is registered in peripheral collisions. In central collisions, both mesons show suppression relative to the expectations from the p+p yield scaled by the number of binary nucleon-nucleon collisions in the Cu+Cu system. In the pT range 25 GeV/c, the strange mesons ( K0S, K*0) similarly to the #30;? meson with hidden strangeness, show an intermediate suppression between the more suppressed light quark mesons (?0) and the nonsuppressed baryons (p, p-bar). At higher transverse momentum, pT > 5 GeV/c, production of all particles is similarly suppressed by a factor of ?2. (auth)

  18. Multi-functional ultrathin PdxCu1-x and Pt~PdxCu1-x one-dimensional nanowire motifs for various small molecule oxidation reactions

    SciTech Connect (OSTI)

    Liu, Haiqing; Wong, Stanislaus S.; Adzic, Radoslav R.

    2015-11-18

    Developing novel electrocatalysts for small molecule oxidation processes, including formic acid oxidation (FAOR), methanol oxidation reaction (MOR), and ethanol oxidation reaction (EOR), denoting the key anodic reactions for their respective fuel cell configurations, is a significant and relevant theme of recent efforts in the field. Herein, in this report, we demonstrated a concerted effort to couple and combine the benefits of small size, anisotropic morphology, and tunable chemical composition in order to devise a novel “family” of functional architectures. In particular, we have fabricated not only ultrathin 1-D Pd1–xCux alloys but also Pt-coated Pd1–xCux (i.e., Pt~Pd1–xCux; herein the ~ indicates an intimate association, but not necessarily actual bond formation, between the inner bimetallic core and the Pt outer shell) core–shell hierarchical nanostructures with readily tunable chemical compositions by utilizing a facile, surfactant-based, wet chemical synthesis coupled with a Cu underpotential deposition technique. Our main finding is that our series of as-prepared nanowires are functionally flexible. More precisely, we demonstrate that various examples within this “family” of structural motifs can be tailored for exceptional activity with all 3 of these important electrocatalytic reactions. In particular, we note that our series of Pd1–xCux nanowires all exhibit enhanced FAOR activities as compared with not only analogous Pd ultrathin nanowires but also commercial Pt and Pd standards, with Pd9Cu representing the “optimal” composition. Moreover, our group of Pt~Pd1–xCux nanowires consistently outperformed not only commercial Pt NPs but also ultrathin Pt nanowires by several fold orders of magnitude for both the MOR and EOR reactions in alkaline media. As a result, the variation of the MOR and EOR performance with the chemical composition of our ultrathin Pt~Pd1–xCux nanowires was also discussed.

  19. Location of gap nodes in the organic superconductors {kappa}-(ET){sub 2}Cu(NCS){sub 2} and {kappa}-(ET){sub 2}Cu[N(CN){sub 2}Br determined by magnetocalorimetry.

    SciTech Connect (OSTI)

    Malone, L.; Taylor, O. J.; Schlueter, J. A.; Carrington, A.; Materials Science Division; Univ. Bristol

    2010-07-16

    We report specific-heat measurements of the organic superconductors {kappa}-(ET){sub 2}Cu(NCS){sub 2} and {kappa}-(ET){sub 2}Cu[N(CN){sub 2}]Br. When the magnetic field is rotated in the highly conducting planes at low temperature (T = 0.4 K), we observe clear oscillations of specific heat which have a strong fourfold component. The observed strong field and temperature dependence of this fourfold component identifies it as originating from nodes in the superconducting energy gap which point along the in-plane crystal axes (d{sub xy} symmetry).

  20. Microwave-assisted synthesis and photovoltaic measurements of CuInS{sub 2} nanoparticles prepared by using metalorganic precursors

    SciTech Connect (OSTI)

    Hosseinpour-Mashkani, S. Mostafa; Mohandes, Fatemeh; Salavati-Niasari, Masoud; Institute of Nano Science and Nano Technology, University of Kashan, Kashan, P.O. Box 87317-51167, Islamic Republic of Iran ; Venkateswara-Rao, K.

    2012-11-15

    Highlights: ? CuInS{sub 2} nanoparticles were prepared using complexes via a microwave-assisted method. ? The effect of preparation parameters on the morphology of CuInS{sub 2} was investigated. ? The as-deposited CdS/CuInS{sub 2} films were used for the photovoltaic measurements. -- Abstract: In this work, CuInS{sub 2} (CIS) nanoparticles have been synthesized with the aid of (1,8-diamino-3,6-dioxaoctan)copper(II) sulfate ([Cu(DADO)]SO{sub 4}) and bis(propylenediamine)copper(II) sulfate ([Cu(pn){sub 2}]SO{sub 4}) complexes as copper precursor in the presence of microwave irradiation. Besides, L-cystine, InCl{sub 3}, and sodium dodecyl sulfate (SDS) were applied as sulfur source, indium precursor, and capping agent, respectively. To investigate the effect of preparation parameters like microwave power and irradiation time on the morphology and particle size of CuInS{sub 2}, the experiment was carried out at different conditions. The as-synthesized CuInS{sub 2} nanoparticles were characterized by XRD, FT-IR, PL, SEM, TEM, and EDS. The XRD results showed that pure tetragonal CuInS{sub 2} could be only obtained after annealing at 400 C for 2 h. The SEM images indicated that with decreasing the microwave power and irradiation time, particle size of CuInS{sub 2} nanoparticles decreased. To fabricate a solar cell, CdS film was directly deposited on top of the CIS film prepared by Doctor's blade method through chemical bath deposition. The as-deposited CdS/CuInS{sub 2} films were used for the photovoltaic measurements.

  1. Modification of carbon nanotubes by CuO-doped NiO nanocomposite for use as an anode material for lithium-ion batteries

    SciTech Connect (OSTI)

    Mustansar Abbas, Syed; Tajammul Hussain, Syed; Ali, Saqib; Ahmad, Nisar; Ali, Nisar; Abbas, Saghir; Ali, Zulfiqar

    2013-06-15

    CuO-doped NiO (CuNiO) with porous hexagonal morphology is fabricated via a modified in-situ co-precipitation method and its nanocomposite is prepared with carbon nanotubes (CNTs). The electrochemical properties of CuNiO/CNT nanocomposite are investigated by cyclic voltammetry (CV), galvanostatic chargedischarge tests and electrochemical impedance spectroscopy (EIS). Since Cu can both act as conductor and a catalyst, the CuNiO/CNT nanocomposite exhibits higher initial coulombic efficiency (82.7% of the 2nd cycle) and better capacity retention (78.6% on 50th cycle) than bare CuNiO (78.9% of the 2nd cycle), CuO/CNT (76.8% of the 2nd cycle) and NiO/CNT (77.7% of the 2nd cycle) at the current density of 100 mA /g. This high capacity and good cycling ability is attributed to the partial substitution of Cu{sup +2} for Ni{sup +2}, resulting in an increase of holes concentration, and therefore improved p-type conductivity along with an intimate interaction with CNTs providing large surface area, excellent conduction, mechanical strength and chemical stability. - Graphical abstract: The porous CuNiO/CNT nanocomposite synthesized via a modified co-precipitation method in combination with subsequent calcination was applied in the negative electrode materials for lithium-ion batteries and exhibited high electrochemical performance. - Highlights: CuO doped NiO/CNTs nano composite is achieved via a simple co-precipitation method. Monodispersity, shape and sizes of sample particles is specifically controlled. Good quality adhesion between CNTs and CuNiO is visible from TEM image. High electrochemical performance is achieved. Discharge capacity of 686 mA h/g after 50 cycles with coulombic efficiency (82.5%)

  2. 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.

    2005-03-21

    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.

  3. Synthesis and characterization of CuInS{sub 2} nanostructure by ultrasonic-assisted method and different precursors

    SciTech Connect (OSTI)

    Mousavi-Kamazani, Mehdi; Salavati-Niasari, Masoud; Department of Inorganic Chemistry, Faculty of Chemistry, University of Kashan, Kashan, P.O. Box 87317-51167 ; Emadi, Hamid

    2012-12-15

    Graphical abstract: Display Omitted Highlights: ? CuInS{sub 2} nanoparticles were synthesized by ultrasonic assisted method. ? CuInS{sub 2} nanoparticles obtained after annealing at 350 C for 1 h. ? The effect of some parameters including ultrasonic was investigated. -- Abstract: This paper reports on the synthesis of CuInS{sub 2} nanostructure via an ultrasonic assisted method by employing different sulfur source. Morphology, structure and composition of the obtained products were characterized by X-ray diffraction (XRD), energy dispersive X-ray analysis (EDX), scanning electron microscope (SEM), infrared (IR) spectrum, and photoluminescence (PL) spectroscopy. The effects of ultrasonic irradiation, power and time of irradiation, surfactant, and type of copper source were investigated.

  4. Effect of electronic structures on catalytic properties of CuNi alloy and Pd in MeOH-related reactions

    SciTech Connect (OSTI)

    Tsai, An-Pang; Kimura, Tomofumi; Suzuki, Yukinori; Kameoka, Satoshi; Shimoda, Masahiko; Ishii, Yasushi

    2013-04-14

    We investigated the catalytic properties of a CuNi solid solution and Pd for methanol-related reactions and associated valence electronic structures. Calculations and X-ray photoelectron spectroscopy measurements revealed that the CuNi alloy has a similar valence electronic structure to Pd and hence they exhibited similar CO selectivities in steam reforming of methanol and decomposition of methanol. Samples prepared by various processes were found to have similar CO selectivities. We conjecture that alloying of Cu and Ni dramatically alters the valence electronic structures, making it similar to that of Pd so that the alloy exhibits similar catalytic properties to Pd. First-principles slab calculations of surface electronic structures support this conjecture.

  5. Enhanced hydrogenation and reduced lattice distortion in size selected Pd-Ag and Pd-Cu alloy nanoparticles

    SciTech Connect (OSTI)

    Sengar, Saurabh K.; Mehta, B. R.; Kulriya, P. K.; Khan, S. A.

    2013-10-21

    Important correlation between valence band spectra and hydrogenation properties in Pd alloy nanoparticles is established by studying the properties of size selected and monocrystalline Pd, Ag, Cu, Pd-Ag, and Pd-Cu nanoparticles. The X-ray photoelectron spectroscopy and elastic recoil detection analysis show that size induced Pd4d centroid shift is related to enhanced hydrogenation with H/Pd ratio of 0.57 and 0.49 in Pd-Ag and Pd-Cu nanoparticles in comparison to reported bulk values of 0.2 and 0.1, respectively. Pd-alloy nanoparticles show lower hydrogen induced lattice distortion. The reduced distortion and higher hydrogen reactivity of Pd-alloy nanoparticles is important for numerous hydrogen related applications.

  6. First-principles study of direct and narrow band gap semiconducting β -CuGaO2

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Nguyen, Manh Cuong; Zhao, Xin; Wang, Cai-Zhuang; Ho, Kai-Ming

    2015-04-16

    Semiconducting oxides have attracted much attention due to their great stability in air or water and the abundance of oxygen. Recent success in synthesizing a metastable phase of CuGaO2 with direct narrow band gap opens up new applications of semiconducting oxides as absorber layer for photovoltaics. Using first-principles density functional theory calculations, we investigate the thermodynamic and mechanical stabilities as well as the structural and electronic properties of the β-CuGaO2 phase. Our calculations show that the β-CuGaO2 structure is dynamically and mechanically stable. The energy band gap is confirmed to be direct at the Γ point of Brillouin zone. Inmore » conclusion, the optical absorption occurs right at the band gap edge and the density of states near the valance band maximum is large, inducing an intense absorption of light as observed in experiment.« less

  7. 15.4% CuIn1-XGaXSe2-Based Photovoltaic Cells from Solution-Based Precursor Films

    SciTech Connect (OSTI)

    Bhattacharya, R. N.; Batchelor, W.; Contreras, M. A.; Noufi, R. N.; Hiltner, J. F.; Sites, J. R.

    1999-05-25

    We have fabricated 15.4%- and 12.4%-efficient CuIn1-XGaXSe2 (CIGS)-based photovoltaic devices from solution-based electrodeposition (ED) and electroless-deposition (EL) precursors. As-deposited precursors are Cu-rich CIGS. Additional In, Ga, and Se are added to the ED and EL precursor films by physical vapor deposition (PVD) to adjust the final film composition to CuIn1-XGaXSe2. The ED and EL device parameters are compared with those of a recent world record, an 18.8%-efficient PVD device. The tools used for comparison are current voltage, capacitance voltage, and spectral response characteristics.

  8. Low voltage tunneling magnetoresistance in CuCrO{sub 2}-based semiconductor heterojunctions at room temperature

    SciTech Connect (OSTI)

    Li, X. R.; Han, M. J.; Shan, C.; Hu, Z. G. Zhu, Z. Q.; Chu, J. H.; Wu, J. D.

    2014-12-14

    CuCrO{sub 2}-based heterojunction diodes with rectifying characteristics have been fabricated by combining p-type Mg-doped CuCrO{sub 2} and n-type Al-doped ZnO. It was found that the current for the heterojunction in low bias voltage region is dominated by the trap-assisted tunneling mechanism. Positive magnetoresistance (MR) effect for the heterojunction can be observed at room temperature due to the tunneling-induced antiparallel spin polarization near the heterostructure interface. The MR effect becomes enhanced with the magnetic field, and shows the maximum at a bias voltage around 0.5 V. The phenomena indicate that the CuCrO{sub 2}-based heterojunction is a promising candidate for low-power semiconductor spintronic devices.

  9. Film Deposition, Cryogenic RF Testing and Materials Analysis of a Nb/Cu Single Cell SRF Cavity

    SciTech Connect (OSTI)

    Zhao, Xin; Geng, Rongli; Palczerski, Ari; Li, Yongming

    2013-09-01

    In this study, we present preliminary results on using a cathodic-arc-discharge Nb plasma ion source to establish a Nb film-coated single-cell Cu cavity for SRF research. The polycrystalline Cu cavity was fabricated and mirror-surface-finished by a centrifugal barrel polishing (CBP) process at Jefferson Lab. Special pre-coating processes were conducted, in order to create a template-layer for follow-on Nb grain thickening. A sequence of cryogenic RF testing demonstrated that the Nb film does show superconductivity. But the quality factor of this Nb/Cu cavity is low as a result of high residual surface resistance. We are conducting a thorough materials characterization to explore if some microstructural defects or hydrogen impurities, led to such a low quality factor.

  10. Tuned sensitivity towards H{sub 2}S and NH{sub 3} with Cu doped barium strontium titanate materials

    SciTech Connect (OSTI)

    Simion, C. E. Teodorescu, V. S.; Stănoiu, A.; Sackmann, A.; Ruşti, C. F.; Piticescu, R. M.

    2014-11-05

    The different amount of Cu-doped Barium Strontium Titanate (BST) thick film materials have been tested for their gas-sensing performances towards NH{sub 3} and H{sub 2}S under dry and 50% relative humidity (RH) background conditions. The optimum NH{sub 3} sensitivity was attained with 0.1mol% Cu-doped BST whereas the selective detection of H{sub 2}S was highlighted using 5mol% Cu-doped BST material. No cross-sensitivity effects to CO, NO{sub 2}, CH{sub 4} and SO{sub 2} were observed for all tested materials operated at their optimum temperature (200°C) under humid conditions (50% RH). The presence of humidity clearly enhances the gas sensitivity to NH{sub 3} and H{sub 2}S detection.

  11. Effect of filler metal composition on the strength of yttria stabilized zirconia joints brazed with Pd-Ag-CuOx

    SciTech Connect (OSTI)

    Darsell, Jens T.; Weil, K. Scott

    2008-09-08

    The Ag-CuOx system is of interest to be used to be used as an air braze filler metal for joining high temperature electrochemical devices. Previous work has shown that the melting temperatures can be increased by adding palladium to Ag-CuOx and it is expected that this may aid high temperature stability. This work compares the room temperature bend strength of joints made between yttria-stabilized zirconia (YSZ) air brazed using Ag-CuOx without palladium and with 5 and 15mol% palladium additions. It has been found that in general palladium decreases joint strength, especially in low copper oxide compositions filler metals. At high copper oxide contents, brittle fracture through both copper oxide rich phases and the YSZ limits joint strength.

  12. Multi-functional ultrathin PdxCu1-x and Pt~PdxCu1-x one-dimensional nanowire motifs for various small molecule oxidation reactions

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Liu, Haiqing; Wong, Stanislaus S.; Adzic, Radoslav R.

    2015-11-18

    Developing novel electrocatalysts for small molecule oxidation processes, including formic acid oxidation (FAOR), methanol oxidation reaction (MOR), and ethanol oxidation reaction (EOR), denoting the key anodic reactions for their respective fuel cell configurations, is a significant and relevant theme of recent efforts in the field. Herein, in this report, we demonstrated a concerted effort to couple and combine the benefits of small size, anisotropic morphology, and tunable chemical composition in order to devise a novel “family” of functional architectures. In particular, we have fabricated not only ultrathin 1-D Pd1–xCux alloys but also Pt-coated Pd1–xCux (i.e., Pt~Pd1–xCux; herein the ~ indicatesmore » an intimate association, but not necessarily actual bond formation, between the inner bimetallic core and the Pt outer shell) core–shell hierarchical nanostructures with readily tunable chemical compositions by utilizing a facile, surfactant-based, wet chemical synthesis coupled with a Cu underpotential deposition technique. Our main finding is that our series of as-prepared nanowires are functionally flexible. More precisely, we demonstrate that various examples within this “family” of structural motifs can be tailored for exceptional activity with all 3 of these important electrocatalytic reactions. In particular, we note that our series of Pd1–xCux nanowires all exhibit enhanced FAOR activities as compared with not only analogous Pd ultrathin nanowires but also commercial Pt and Pd standards, with Pd9Cu representing the “optimal” composition. Moreover, our group of Pt~Pd1–xCux nanowires consistently outperformed not only commercial Pt NPs but also ultrathin Pt nanowires by several fold orders of magnitude for both the MOR and EOR reactions in alkaline media. As a result, the variation of the MOR and EOR performance with the chemical composition of our ultrathin Pt~Pd1–xCux nanowires was also discussed.« less

  13. Direct production of nanostructured copper-nickel (Cu-Ni) alloy particles

    SciTech Connect (OSTI)

    Apaydin, Ramazan Oguzhan; Ebin, Burcak; Gurmen, Sebahattin

    2013-12-16

    Copper-Nickel (CuNi) nanostructured alloy particles were produced by Ultrasonic Spray Pyrolysis and Hydrogen Reduction Method (USP-HR) from high purity copper and nickel nitrate aqueous solutions. The effect of the precursor solution in the range of 0.1 and 0.5 mol/L on the morphology and crystallite size of CuNi nanoparticles were investigated under 2 h running time, 700 °C operating temperature and 0.5 L/min H{sub 2} flow rate. Particle size, morphology, composition and crystallite structure were characterized by Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS) and X-Ray Diffraction (XRD). Particle characterization studies show that nanostructured alloy particles have cubic crystal structure and they are in submicron size range with spherical morphology. The crystallite sizes of the particles calculated with Scherrer formula are 40 and 34 nm and average particles sizes observed from the SEM images are 300 and 510 nm for each experiment respectively.

  14. Advanced Precursor Reaction Processing for Cu(InGa)(SeS)2 Solar Cells

    SciTech Connect (OSTI)

    Shafarman, William N.

    2015-10-12

    This project “Advanced Precursor Reaction Processing for Cu(InGa)(SeS)2 Solar Cells”, completed by the Institute of Energy Conversion (IEC) at the University of Delaware in collaboration with the Department of Chemical Engineering at the University of Florida, developed the fundamental understanding and technology to increase module efficiency and improve the manufacturability of Cu(InGa)(SeS)2 films using the precursor reaction approach currently being developed by a number of companies. Key results included: (1) development of a three-step H2Se/Ar/H2S reaction process to control Ga distribution through the film and minimizes back contact MoSe2 formation; (2) Ag-alloying to improve precursor homogeneity by avoiding In phase agglomeration, faster reaction and improved adhesion to allow wider reaction process window; (3) addition of Sb, Bi, and Te interlayers at the Mo/precursor junction to produce more uniform precursor morphology and improve adhesion with reduced void formation in reacted films; (4) a precursor structure containing Se and a reaction process to reduce processing time to 5 minutes and eliminate H2Se usage, thereby increasing throughput and reducing costs. All these results were supported by detailed characterization of the film growth, reaction pathways, thermodynamic assessment and device behavior.

  15. Complex conductance of ultrathin La2-xSrxCuO4 films and heterostructures

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    V. A. Gasparov; Bozovic, I.

    2015-10-23

    We used atomic-layer molecular beam epitaxy to synthesize bilayers of a cuprate metal (La1.55Sr0.45CuO4) and a cuprate insulator (La2CuO4), in which each layer is just one unit cells thick. We have studied the magnetic field and temperature dependence of the complex sheet conductance, σ(ω), of these films. Experiments have been carried out at frequencies between 2 and 50 MHz using the single-spiral coil technique. We found that: (i) the inductive response starts at ΔT = 3 K lower temperatures than Re σ(T), which in turn is characterized by a peak close to the transition, (ii) this shift is almost constantmore » with magnetic field up to 14 mT; (iii) ΔT increases sharply up to 4 K at larger fields and becomes constant up to 8 T; (iv) the vortexdiffusion constant D(T) is not linear with T at low temperatures as in the case of free vortices, but is rather exponential due to pinning of vortex cores, and (v) the dynamic Berezinski–Kosterlitz–Thouless (BKT) transition temperature occurs at the point where Y=(lω/ξ+)2 = 1. As a result, our experimental results can be described well by the extended dynamic theory of the BKT transition and dynamics of bound vortex–antivortex pairs with short separation lengths.« less

  16. Enhanced O2 selectivity versus N2 by partial metal substitution in Cu-BTC

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Sava Gallis, Dorina F.; Parkes, Marie V.; Greathouse, Jeffery A.; Zhang, Xiaoyi; Nenoff, Tina M.

    2015-03-05

    Here we describe the homogeneous substitution of Mn, Fe and Co at various levels into a prototypical metal-organic framework (MOF), namely Cu-BTC (HKUST-1), and the effect of that substitution on preferential gas sorption. Using a combination of density functional theory (DFT) calculations, postsynthetic metal substitutions, materials characterization, and gas sorption testing, we demonstrate that the identity of the metal ion has a quantifiable effect on their oxygen and nitrogen sorption properties at cryogenic temperatures. An excellent correlation is found between O2/N2 selectivities determined experimentally at 77 K and the difference in O2 and N2 binding energies calculated from DFT modelingmore » data: Mn > Fe > Co > Cu. Room temperature gas sorption studies were also performed and correlated with metal substitution. The Fe-exchanged sample shows a significantly higher nitrogen isosteric heat of adsorption at temperatures close to ambient conditions (273 K - 298 K) as compared to all other metals studied, indicative of favorable interactions between N2 and coordinatively unsaturated Fe metal centers. Furthermore, differences in gas adsorption results at cryogenic and room temperatures are evident; they are explained by comparing experimental results with DFT binding energies (0 K) and room temperature Grand Canonical Monte Carlo simulations.« less

  17. Novel thin-film CuInSe sub 2 fabrication

    SciTech Connect (OSTI)

    Mooney, G.D.; Hermann, A.M. )

    1992-03-01

    This report describes research in Rapid Thermal Processing (RTP), a process that allows the formation of CuInSe{sub 2} without the use of H{sub 2}Se. RTP is a well-established method of rapidly achieving temperatures necessary to melt and recrystallize materials such as Si and and silicides. RTP processes can rapidly and uniformly heat large surface areas to hundreds of degrees Celsius. RTP is the most promising method of rapid recrystallization studied to date, being readily scalable from the research to the production level. The approach to the experiment was divided into two sections: (1) fabricating the precursor film and (2) processing the precursor film. The objective of the first phase of the work was to fabricate the thin films by RTP, then fully characterize them, to demonstrate the viability of the process as a method by which to make device-quality CuInSe{sub 2}. The second phase was to demonstrate that material made by this method could be used to make an active photovoltaic device. 24 refs.

  18. Remarkably robust and correlated coherence and antiferromagnetism in (Ce1-x Lax)Cu?Ge?

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Hodovanets, H.; Budko, S.? L.; Straszheim, W.? E.; Taufour, V.; Mun, E.? D.; Kim, H.; Flint, R.; Canfield, P.? C.

    2015-06-08

    We present magnetic susceptibility, resistivity, specific heat, and thermoelectric power measurements on (Ce1-x Lax)Cu?Ge? single crystals (0 ? x ? 1). With La substitution, the antiferromagnetic temperature TN is suppressed in an almost linear fashion and moves below 0.36 K, the base temperature of our measurements for x > 0.8. Surprisingly, in addition to robust antiferromagnetism, the system also shows low temperature coherent scattering below Tcoh up to ~ 0.9 of La, indicating a small percolation limit ~ 9% of Ce. Tcoh as a function of magnetic field was found to have different behavior for x more> 0.9. Remarkably, (Tcoh) at H = 0 was found to be linearly proportional to TN. The jump in the magnetic specific heat ?Cm at TN as a function of TK/TN for (Ce1-x Lax)Cu?Ge? follows the theoretical prediction based on the molecular field calculation for the S = 1/2 resonant level model.less

  19. Manufacturing technology development for CuInGaSe sub 2 solar cell modules

    SciTech Connect (OSTI)

    Stanbery, B.J. )

    1991-11-01

    The report describes research performed by Boeing Aerospace and Electronics under the Photovoltaic Manufacturing Technology project. We anticipate that implementing advanced semiconductor device fabrication techniques to the production of large-area CuIn{sub 1-x}Ga{sub x}Se{sub 2} (CIGS)/Cd{sub 1-y}Zn{sub y}S/ZnO monolithically integrated thin-film solar cell modules will enable 15% median efficiencies to be achieved in high-volume manufacturing. We do not believe that CuInSe{sub 2} (CIS) can achieve this efficiency in production without sufficient gallium to significantly increase the band gap, thereby matching it better to the solar spectrum (i.e., x{ge}0.2). Competing techniques for CIS film formation have not been successfully extended to CIGS devices with such high band gaps. The SERI-confirmed intrinsic stability of CIS-based photovoltaics renders them far superior to a-Si:H-based devices, making a 30-year module lifetime feasible. The minimal amounts of cadmium used in the structure we propose, compared to CdTe-based devices, makes them environmentally safer and more acceptable to both consumers and relevant regulatory agencies. Large-area integrated thin-film CIGS modules are the product most likely to supplant silicon modules by the end of this decade and enable the cost improvements which will lead to rapid market expansion.

  20. Properties of Cu(In,Ga,Al)Se{sub 2} thin films fabricated by magnetron sputtering

    SciTech Connect (OSTI)

    Hameed, Talaat A.; Cao, Wei; Mansour, Bahiga A.; Elzawaway, Inas K.; Abdelrazek, El-Metwally M.; Elsayed-Ali, Hani E.

    2015-05-15

    Cu(In,Ga,Al)Se{sub 2} (CIGAS) thin films were studied as an alternative absorber layer material to Cu(In{sub x}Ga{sub 1?x})Se{sub 2}. CIGAS thin films with varying Al content were prepared by magnetron sputtering on Si(100) and soda-lime glass substrates at 350?C, followed by postdeposition annealing at 520?C for 5 h in vacuum. The film composition was measured by an electron probe microanalyzer while the elemental depth profiles were determined by secondary ion mass spectrometry. X-ray diffraction studies indicated that CIGAS films are single phase with chalcopyrite structure and that the (112) peak clearly shifts to higher 2? values with increasing Al content. Scanning electron microscopy images revealed dense and well-defined grains, as well as sharp CIGAS/Si(100) interfaces for all films. Atomic force microscopy analysis indicated that the roughness of CIGAS films decreases with increasing Al content. The bandgap of CIGAS films was determined from the optical transmittance and reflectance spectra and was found to increase as Al content increased.

  1. CuYb{sub 2}Ge{sub 4}O{sub 12}, a new bidimensionally tunneled structure

    SciTech Connect (OSTI)

    Campa, J.A.; Cascales, C.; Gueierrez-Puebla, E.; Monge, M.A.; Rasines, I.; Ruiz Valero, C.

    1996-06-01

    Employing CuO as self flux crystals of CuYb{sub 2}Ge{sub 4}O{sub 12} have been grown for the first time. The crystal structure of CuYb{sub 2}Ge{sub 4}O{sub 12} has been determined by single-crystal X-ray diffraction in the triclinic P1 (No. 2) space group to an R value of 6.1%, with (a) = 7.156(2) {Angstrom}, (b) = 7.937(3) {Angstrom}, (c) = 4.905(3) {Angstrom}, {alpha} = 86.63(3){degrees}, {Beta} = 102.41(4){degrees}, {gamma}=1114.12(3){degrees}, V = 248.2(2) {Angstrom}{sup 3}, Z = 1, and D{sub c} = 5.97 gcm{sup {minus}3}. The novel tridimensional CuYb{sub 2}Ge{sub 4}O{sub 12} structure type can be conceived as formed by layers of (GeO{sub 4}){sub 4} units of vertex-sharing GeO{sub 4} squares connecting (GeO{sub 4}){sub 4} units, with channels or tunnels of size up to 4.08 {Angstrom} in the a and c directions. A comparison is made between the structure types of the title germanate and recently reported CuNd{sub 2}Ge{sub 2}O{sub 8}. The temperature dependence from 350 to 1.8 K of the reciprocal dc magnetic susceptibility for CuYb{sub 2}Ge{sub 4}O{sub 12} is shown and presents a deviation from linearity over the whole temperature range. The infrared spectrum between 1000 and 100 cm{sup {minus}1} is given and related with those of comparable species.

  2. Electronic and Magnetic Properties of Li1.5Mn0.5As Alloys in the Cu2Sb

    Office of Scientific and Technical Information (OSTI)

    Structure (Conference) | SciTech Connect Conference: Electronic and Magnetic Properties of Li1.5Mn0.5As Alloys in the Cu2Sb Structure Citation Details In-Document Search Title: Electronic and Magnetic Properties of Li1.5Mn0.5As Alloys in the Cu2Sb Structure Authors: Fong, C Y ; Damewood, L ; Yang, L H ; Felser, C Publication Date: 2012-12-03 OSTI Identifier: 1072409 Report Number(s): LLNL-PROC-606953 DOE Contract Number: W-7405-ENG-48 Resource Type: Conference Resource Relation: Conference:

  3. Electronic and Magnetic Properties of Li1.5Mn0.5As Alloys in the Cu2Sb

    Office of Scientific and Technical Information (OSTI)

    Structure (Conference) | SciTech Connect Conference: Electronic and Magnetic Properties of Li1.5Mn0.5As Alloys in the Cu2Sb Structure Citation Details In-Document Search Title: Electronic and Magnetic Properties of Li1.5Mn0.5As Alloys in the Cu2Sb Structure × You are accessing a document from the Department of Energy's (DOE) SciTech Connect. This site is a product of DOE's Office of Scientific and Technical Information (OSTI) and is provided as a public service. Visit OSTI to utilize

  4. Novel instabilities in the oxidation of a nimonic alloy when YBaCuO is deposited upon it

    SciTech Connect (OSTI)

    Newcomb, S.B.; Soylu, B.; Stobbs, W.M. )

    1990-10-01

    When an YBaCuO film is deposited onto a Nimonic 80A alloy substrate using a plasma technique there is extensive inter-reaction. The microstructural and compositional relationships between the layered products in this interfacial scaling process are described using data obtained by conventional edge-on TEM techniques. Results demonstrate the way in which the segregation of chromium to the YBaCuO overlayer dominates the scaling behavior that is seen, despite the formation of intermediate layers which would normally have been expected to act as diffusion barriers, and highlight the potential difficulties in making well behaved electrical contacts for this superconductor.

  5. Method of producing superconducting fibers of YBa[sub 2]Cu[sub 3]O[sub x

    DOE Patents [OSTI]

    Schwartzkopf, L.A.; Ostenson, J.E.; Finnemore, D.K.

    1990-11-13

    Fibers of YBa[sub 2]Cu[sub 3]O[sub x] have been produce by pendant drop melt extraction. This technique involves the end of a rod of YBa[sub 2]Cu[sub 3]O[sub x] melted with a hydrogen-oxygen torch, followed by lowering onto the edge of a spinning wheel. The fibers are up to 10 cm in length with the usual lateral dimensions, ranging from 20 [mu]m to 125 [mu]m. The fibers require a heat treatment to make them superconducting.

  6. Long-term superelastic cycling at nano-scale in Cu-Al-Ni shape memory alloy micropillars

    SciTech Connect (OSTI)

    San Juan, J. Gómez-Cortés, J. F.

    2014-01-06

    Superelastic behavior at nano-scale has been studied along cycling in Cu-Al-Ni shape memory alloy micropillars. Arrays of square micropillars were produced by focused ion beam milling, on slides of [001] oriented Cu-Al-Ni single crystals. Superelastic behavior of micropillars, due to the stress-induced martensitic transformation, has been studied by nano-compression tests during thousand cycles, and its evolution has been followed along cycling. Each pillar has undergone more than thousand cycles without any detrimental evolution. Moreover, we demonstrate that after thousand cycles they exhibit a perfectly reproducible and completely recoverable superelastic behavior.

  7. Thin-film transistors based on p-type Cu{sub 2}O thin films produced at room temperature

    SciTech Connect (OSTI)

    Fortunato, Elvira; Figueiredo, Vitor; Barquinha, Pedro; Elamurugu, Elangovan; Goncalves, Goncalo; Martins, Rodrigo; Park, Sang-Hee Ko; Hwang, Chi-Sun

    2010-05-10

    Copper oxide (Cu{sub 2}O) thin films were used to produce bottom gate p-type transparent thin-film transistors (TFTs). Cu{sub 2}O was deposited by reactive rf magnetron sputtering at room temperature and the films exhibit a polycrystalline structure with a strongest orientation along (111) plane. The TFTs exhibit improved electrical performance such as a field-effect mobility of 3.9 cm{sup 2}/V s and an on/off ratio of 2x10{sup 2}.

  8. Quasiparticle dynamics across the full Brillouin zone of Bi2Sr2CaCu2O8+δ

    Office of Scientific and Technical Information (OSTI)

    traced with ultrafast time and angle-resolved photoemission spectroscopy (Journal Article) | SciTech Connect Quasiparticle dynamics across the full Brillouin zone of Bi2Sr2CaCu2O8+δ traced with ultrafast time and angle-resolved photoemission spectroscopy Citation Details In-Document Search Title: Quasiparticle dynamics across the full Brillouin zone of Bi2Sr2CaCu2O8+δ traced with ultrafast time and angle-resolved photoemission spectroscopy A hallmark in the cuprate family of

  9. Quadruple-layered perovskite (CuCl)Ca{sub 2}NaNb{sub 4}O{sub 13}

    SciTech Connect (OSTI)

    Kitada, A.; Tsujimoto, Y.; Yamamoto, T. [Department of Energy and Hydrocarbon Chemistry, Faculty of Engineering, Kyoto University, Nishikyo, Kyoto 615-8510 (Japan); Department of Chemistry, Graduate School of Science, Kyoto University, Kyoto 606-8502 (Japan); Kobayashi, Y. [Department of Energy and Hydrocarbon Chemistry, Faculty of Engineering, Kyoto University, Nishikyo, Kyoto 615-8510 (Japan); Narumi, Y. [Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581 (Japan); Institute for Materials Research, Tohoku University, Katahira 2-1-1, Sendai 980-8577 (Japan); Kindo, K. [Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581 (Japan); Aczel, A.A.; Luke, G.M. [Department of Physics and Astronomy, McMaster University, Hamilton, Ontario, L8S 4M1 (Canada); Uemura, Y.J. [Department of Physics, Columbia University, New York, NY 10027 (United States); Kiuchi, Y.; Ueda, Y. [Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581 (Japan); Yoshimura, K. [Department of Chemistry, Graduate School of Science, Kyoto University, Kyoto 606-8502 (Japan); Ajiro, Y. [Department of Energy and Hydrocarbon Chemistry, Faculty of Engineering, Kyoto University, Nishikyo, Kyoto 615-8510 (Japan); Kageyama, H., E-mail: kage@scl.kyoto-u.ac.jp [Department of Energy and Hydrocarbon Chemistry, Faculty of Engineering, Kyoto University, Nishikyo, Kyoto 615-8510 (Japan); Department of Chemistry, Graduate School of Science, Kyoto University, Kyoto 606-8502 (Japan); Institute for Integrated Cell-Material Sciences, Kyoto University, Sakyo, Kyoto 606-8501 (Japan); CREST, Japan Science and Technology Agency, Kawaguchi 332-0012 (Japan)

    2012-01-15

    We will present the synthesis, structure and magnetic properties of a new quadruple-layered perovskite (CuCl)Ca{sub 2}NaNb{sub 4}O{sub 13}. Through a topotactic ion-exchange reaction with CuCl{sub 2}, the precursor RbCa{sub 2}NaNb{sub 4}O{sub 13} presumably having an incoherent octahederal tliting changes into (CuCl)Ca{sub 2}NaNb{sub 4}O{sub 13} with a 2a{sub p} Multiplication-Sign 2a{sub p} Multiplication-Sign 2c{sub p} superstructure (tetragonal; a=7.73232(5) A, c=39.2156(4) A). The well-defined superstructure for the ion-exchanged product should be stabilized by the inserted CuCl{sub 4}O{sub 2} octahedral layers that firmly connect with neighboring perovskite layers. Magnetic studies show the absence of long-range magnetic ordering down to 2 K despite strong in-plane interactions. Aleksandrov Prime s group theory and Rietveld refinement of synchrotron X-ray diffraction data suggest the structure to be of I4/mmm space group with in-phase tilting along the a and b axes, a two-tilt system (++0). - Graphical Abstract: We present a quadruple-layered copper oxyhalide (CuCl)Ca{sub 2}NaNb{sub 4}O{sub 13} synthesized through a topotactic ion-exchange reaction of RbCa{sub 2}NaNb{sub 4}O{sub 13} with CuCl{sub 2}. The compound has a well-defined superstructure. Magnetic studies suggest the absence of magnetic order even at 2 K. Highlights: Black-Right-Pointing-Pointer (CuCl)Ca{sub 2}NaNb{sub 4}O{sub 13} was prepared by ion-exchange reaction of RbCa{sub 2}NaNb{sub 4}O{sub 13} with CuCl{sub 2}. Black-Right-Pointing-Pointer Compound has a 2a{sub p} Multiplication-Sign 2a{sub p} Multiplication-Sign 2c{sub p} superstructure (tetragonal; a=7.73 A, c=39.21 A). Black-Right-Pointing-Pointer Such a well-defined superstructure was not observed in the precursor compound. Black-Right-Pointing-Pointer Aleksandrov Prime s theory and Rietveld study suggest a (++0) octahedral tilting (I4/mmm). Black-Right-Pointing-Pointer Magnetic studies revealed the absence of magnetic order down to 2 K.

  10. Direct observation of Fermi surface in YBa sub 2 Cu sub 3 O sub 7 minus. delta

    SciTech Connect (OSTI)

    Haghighi, H.; Kaiser, J.H.; Rayner, S.; West, R.N.; Liu, J.Z.; Shelton, R.; Howell, R.H.; Solal, F.; Fluss, M.J. University of California at Davis, Davis, California 95616 Lawrence Livermore National Laboratory, Livermore, California 94550 )

    1991-07-15

    We have performed a high-precision measurement (5{times}10{sup 8} coincidence counts) of the basal-plane electron-positron momentum density in well oxygenated, twin-free, single crystals of YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}}. The raw, processed, and {bold K}-space reduced spectra unambiguously show a clear image of a major Fermi surface sheet. The form and profile of that image are in substantial quantitative agreement with theoretical predictions of a {Gamma}-{ital X} electron ridge section associated with states in the CuO chains.

  11. Temperature dependence of the sublattice spontaneous magnetization of YBa[sub 2]Cu[sub 3]O[sub 6

    SciTech Connect (OSTI)

    Bucci, C.; Carretta, P.; De Renzi, R.; Guidi, G.; Jang, S.; Rastelli, E.; Tassi, A.; Varotto, M. )

    1993-12-01

    Zero-field copper NMR measurements on YBa[sub 2]Cu[sub 3]O[sub 6] up to 380 K are reported. The temperature dependence of the local magnetic moment at the Cu(2) plane site is compared with the predictions of spin-wave theory, based on the exchange coupling constants obtained from inelastic neutron scattering. The agreement is satisfactory, within the limits of the theoretical approximations, but discrepancies with elastic neutron-scattering results are pointed out and justified in terms of three-dimensional stacking defects.

  12. X-ray absorption near-edge spectra of overdoped La 2 - x Sr x CuO 4 high-

    Office of Scientific and Technical Information (OSTI)

    T c superconductors (Journal Article) | SciTech Connect X-ray absorption near-edge spectra of overdoped La 2 - x Sr x CuO 4 high- T c superconductors Citation Details In-Document Search Title: X-ray absorption near-edge spectra of overdoped La 2 - x Sr x CuO 4 high- T c superconductors Authors: Ahmed, Towfiq ; Das, Tanmoy ; Kas, J. J. ; Lin, Hsin ; Barbiellini, B. ; Vila, Fernando D. ; Markiewicz, R. S. ; Bansil, A. ; Rehr, J. J. Publication Date: 2011-03-11 OSTI Identifier: 1100031 Type:

  13. In-situ energy dispersive x-ray diffraction study of the growth of CuO nanowires by annealing method

    SciTech Connect (OSTI)

    Srivastava, Himanshu; Ganguli, Tapas; Deb, S. K.; Sant, Tushar; Poswal, H. K.; Sharma, Surinder M.

    2013-10-14

    The in-situ growth of CuO nanowires was studied by Energy Dispersive X-ray Diffraction (EDXRD) to observe the mechanism of growth. The study was carried out for comparison at two temperaturesat 500 C, the optimum temperature of the nanowires growth, and at 300 C just below the temperature range of the growth. The in situ observation revealed the successive oxidation of Cu foil to Cu{sub 2}O layer and finally to CuO layer. Further analysis showed the presence of a compressive stress in CuO layer due to interface at CuO and Cu{sub 2}O layers. The compressive stress was found to increase with the growth of the nanowires at 500 C while it relaxed with the growth of CuO layer at 300 C. The present results do not support the existing model of stress relaxation induced growth of nanowires. Based on the detailed Transmission Electron Microscope, Scanning Electron Microscope, and EDXRD results, a microstructure based growth model has been suggested.

  14. In Situ Time-Resolved Characterization of Novel Cu-MoO2 Catalysts During the Water-Gas Shift Reaction

    SciTech Connect (OSTI)

    Wen ,W.; Liu, J.; White, M.; Marinkovic, N.; Hanson, J.; Rodriguez, J.

    2007-01-01

    A novel and active Cu-MoO{sub 2} catalyst was synthesized by partial reduction of a precursor CuMoO{sub 4} mixed-metal oxide with CO or H{sub 2} at 200-250 C. The phase transformations of Cu-MoO{sub 2} during H{sub 2} reduction and the water-gas shift reaction could be followed by In situ time resolved XRD techniques. During the reduction process the diffraction pattern of the CuMoO{sub 4} collapsed and the copper metal lines were observed on an amorphous material background that was assigned to molybdenum oxides. During the first pass of water-gas shift (WGS) reaction, diffraction lines for Cu{sub 6}Mo{sub 5}O{sub 18} and MoO{sub 2} appeared around 350 C and Cu{sub 6}Mo{sub 5}O{sub 18} was further transformed to Cu/MoO{sub 2} at higher temperature. During subsequent passes, significant WGS catalytic activity was observed with relatively stable plateaus in product formation around 350, 400 and 500 C. The interfacial interactions between Cu clusters and MoO{sub 2} increased the water-gas shift catalytic activities at 350 and 400 C.

  15. High-Tc superconductivity at the interface between the CaCuO2 and SrTiO3 insulating oxides

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Di Castro, D.; Cantoni, C.; Ridolfi, F.; Aruta, C.; Tebano, A.; Yang, N.; Balestrino, G.

    2015-09-28

    At interfaces between complex oxides it is possible to generate electronic systems with unusual electronic properties, which are not present in the isolated oxides. One important example is the appearance of superconductivity at the interface between insulating oxides, although, until now, with very low Tc. We report the occurrence of high Tc superconductivity in the bilayer CaCuO2/SrTiO3, where both the constituent oxides are insulating. In order to obtain a superconducting state, the CaCuO2/SrTiO3 interface must be realized between the Ca plane of CaCuO2 and the TiO2 plane of SrTiO3. Only in this case can oxygen ions be incorporated in themore » interface Ca plane, acting as apical oxygen for Cu and providing holes to the CuO2 planes. In addition, a detailed hole doping spatial profile can be obtained by scanning transmission electron microscopy and electron-energy-loss spectroscopy at the O K edge, clearly showing that the (super)conductivity is confined to about 1–2 CaCuO2 unit cells close to the interface with SrTiO3. The results obtained for the CaCuO2/SrTiO3 interface can be extended to multilayered high Tc cuprates, contributing to explaining the dependence of Tc on the number of CuO2 planes in these systems.« less

  16. Selective interlayer ferromagnetic coupling between the Cu spins in YBa2Cu3O7–x grown on top of La0.7Ca0.3MnO3

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Huang, S. W.; Wray, L. Andrew; Jeng, Horng -Tay; Tra, V. T.; Lee, J. M.; Langner, M. C.; Chen, J. M.; Roy, S.; Chu, Y. H.; Schoenlein, R. W.; et al

    2015-11-17

    Studies to date on ferromagnet/d-wave superconductor heterostructures focus mainly on the effects at or near the interfaces while the response of bulk properties to heterostructuring is overlooked. Here we use resonant soft x-ray scattering spectroscopy to reveal a novel c-axis ferromagnetic coupling between the in-plane Cu spins in YBa2Cu3O7–x (YBCO) superconductor when it is grown on top of ferromagnetic La0.7Ca0.3MnO3 (LCMO) manganite layer. This coupling, present in both normal and superconducting states of YBCO, is sensitive to the interfacial termination such that it is only observed in bilayers with MnO2 but not with La0.7Ca0.3O interfacial termination. Thus, such contrasting behaviors,more » we propose, are due to distinct energetic of CuO chain and CuO2 plane at the La0.7Ca0.3O and MnO2 terminated interfaces respectively, therefore influencing the transfer of spin-polarized electrons from manganite to cuprate differently. Our findings suggest that the superconducting/ferromagnetic bilayers with proper interfacial engineering can be good candidates for searching the theorized Fulde-Ferrel-Larkin-Ovchinnikov (FFLO) state in cuprates and studying the competing quantum orders in highly correlated electron systems.« less

  17. Structure and magnetic properties of RE{sub 2}CuIn{sub 3} (RE=Ce, Pr, Nd, Sm and Gd)

    SciTech Connect (OSTI)

    Tyvanchuk, Yuriy B. Szytula, Andrzej; Zarzycki, Arkadiusz; Rodewald, Ute Ch.; Kalychak, Yaroslav M.; Poettgen, Rainer

    2008-12-15

    The ternary copper indides RE{sub 2}CuIn{sub 3}{identical_to}RECu{sub 0.5}In{sub 1.5} (RE=Ce, Pr, Nd, Sm and Gd) were synthesized from the elements in sealed tantalum tubes in an induction furnace. They crystallize with the CaIn{sub 2}-type structure, space group P6{sub 3}/mmc, with a statistical occupancy of copper and indium on the tetrahedral substructure. These indides show homogeneity ranges RECu{sub x}In{sub 2-x}. Single crystal structure refinements were performed for five crystals: CeCu{sub 0.66}In{sub 1.34} (a=479.90(7) pm, c=768.12(15) pm), PrCu{sub 0.52}In{sub 1.48} (a=480.23(7) pm, c=759.23(15) pm), NdCu{sub 0.53}In{sub 1.47} (a=477.51(7) pm, c=756.37(15) pm), SmCu{sub 0.46}In{sub 1.54} (a=475.31(7) pm, c=744.77(15) pm), and GdCu{sub 0.33}In{sub 1.67} (a=474.19(7), c=737.67(15) pm). Temperature-dependent susceptibility measurements show antiferromagnetic ordering at T{sub N}=4.7 K for Pr{sub 2}CuIn{sub 3} and Nd{sub 2}CuIn{sub 3} and 15 K for Sm{sub 2}CuIn{sub 3}. Fitting of the susceptibility data of the samarium compound revealed an energy gap {delta}E=39.7(7) K between the ground and the first excited levels. - Graphical abstract: The CaIn{sub 2}-type structure of Sm{sub 2}CuIn{sub 3}.

  18. Polarization-dependent infrared reflectivity study of Sr???Ca????Cu??O?? under pressure: Charge dynamics, charge distribution, and anisotropy

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Frank, S.; Huecker, M.; Huber, A.; Ammerahl, U.; Kuntscher, C. A.

    2014-12-18

    We present a polarization-dependent infrared reflectivity study of the spin-ladder compound Sr???Ca????Cu??O?? under pressure. The optical response is strongly anisotropic, with the highest reflectivity along the ladders/chains (E?c) revealing a metallic character. For the polarization direction perpendicular to the ladder plane, an insulating behavior is observed. With increasing pressure the optical conductivity for E?c shows a strong increase, which is most pronounced below 2000cm?. According to the spectral weight analysis of the E?c optical conductivity the hole concentration in the ladders increases with increasing pressure and tends to saturate at high pressure. At ~7.5 GPa the number of holes permoreCu atom in the ladders has increased by ??=0.09(0.01), and the Cu valence in the ladders has reached the value +2.33. The optical data suggest that Sr???Ca????Cu??O?? remains electronically highly anisotropic up to high pressure, also at low temperatures.less

  19. Polarization-dependent infrared reflectivity study of Sr???Ca????Cu??O?? under pressure: Charge dynamics, charge distribution, and anisotropy

    SciTech Connect (OSTI)

    Frank, S.; Huecker, M.; Huber, A.; Ammerahl, U.; Kuntscher, C. A.

    2014-12-18

    We present a polarization-dependent infrared reflectivity study of the spin-ladder compound Sr???Ca????Cu??O?? under pressure. The optical response is strongly anisotropic, with the highest reflectivity along the ladders/chains (E?c) revealing a metallic character. For the polarization direction perpendicular to the ladder plane, an insulating behavior is observed. With increasing pressure the optical conductivity for E?c shows a strong increase, which is most pronounced below 2000cm?. According to the spectral weight analysis of the E?c optical conductivity the hole concentration in the ladders increases with increasing pressure and tends to saturate at high pressure. At ~7.5 GPa the number of holes per Cu atom in the ladders has increased by ??=0.09(0.01), and the Cu valence in the ladders has reached the value +2.33. The optical data suggest that Sr???Ca????Cu??O?? remains electronically highly anisotropic up to high pressure, also at low temperatures.

  20. Structural, optical, and magnetic properties of (Co, Cu)-codoped ZnO films with different Co concentrations

    SciTech Connect (OSTI)

    Xu, M. Yuan, H. Zhou, P. F.; Dong, C. J.; You, B.; Duan, M. Y.

    2014-03-07

    Zn{sub 0.99-x}Co{sub x}Cu{sub 0.01}O films with different Co concentrations from 0% to 20% were fabricated by a sol-gel method. Moderate Co doping is found to improve the surface uniformity and crystal quality of the films, and causes a redshift of the band edge of Zn(Co,Cu) films. X-ray photoelectron spectroscopy reveals that the introduction of Co ions causes the valence state of Cu to change from +2 to +1; while at Co concentrations lower than 10%, the Co exists in the +2 valence state. Strong blue emission at ∼420 and 440 nm are observed, decreasing with increasing Co concentration, but becoming strong again as the concentration is increased to 20%. Enhanced room-temperature ferromagnetism is observed for the (Co, Cu)-codoped ZnO films at Co concentrations lower than 10%. These interesting magnetic properties are explained based on charge transfer, together with the defect-related model for ferromagnetism.

  1. Adsorption and Deactivation Characteristics of Cu/ZnO-Based Catalysts for Methanol Synthesis from Carbon Dioxide

    SciTech Connect (OSTI)

    Natesakhawat, Sittichai; Ohodnicki, Paul R., Jr.; Howard, Bret H.; Lekse, Jonathan W.; Baltrus, John P.; Matranga, Christopher

    2013-12-01

    The adsorption and deactivation characteristics of coprecipitated Cu/ZnO-based catalysts were examined and correlated to their performance in methanol synthesis from CO{sub 2} hydrogenation. The addition of Ga{sub 2}O{sub 3} and Y{sub 2}O{sub 3} promoters is shown to increase the Cu surface area and CO{sub 2}/H{sub 2} adsorption capacities of the catalysts and enhance methanol synthesis activity. Infrared studies showed that CO{sub 2} adsorbs spontaneously on these catalysts at room temperature as both monoand bi-dentate carbonate species. These weakly bound species desorb completely from the catalyst surface by 200 C while other carbonate species persist up to 500 C. Characterization using N{sub 2}O decomposition, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM) with energy-dispersive X-ray spectroscopy (EDX) analysis clearly indicated that Cu sintering is the main cause of catalyst deactivation. Ga and Y promotion improves the catalyst stability by suppressing the agglomeration of Cu and ZnO particles under pretreatment and reaction conditions.

  2. Laser-induced fluorescence-cued, laser-induced breakdown spectroscopy biological-agent detection

    SciTech Connect (OSTI)

    Hybl, John D.; Tysk, Shane M.; Berry, Shaun R.; Jordan, Michael P

    2006-12-01

    Methods for accurately characterizing aerosols are required for detecting biological warfare agents. Currently, fluorescence-based biological agent sensors provide adequate detection sensitivity but suffer from high false-alarm rates. Combining single-particle fluorescence analysis with laser-induced breakdown spectroscopy (LIBS) provides additional discrimination and potentially reduces false-alarm rates. A transportable UV laser-induced fluorescence-cued LIBS test bed has been developed and used to evaluate the utility of LIBS for biological-agent detection. Analysis of these data indicates that LIBS adds discrimination capability to fluorescence-based biological-agent detectors.However, the data also show that LIBS signatures of biological agent simulants are affected by washing. This may limit the specificity of LIBS and narrow the scope of its applicability in biological-agent detection.

  3. Properties and features of structure formation CuCr-contact alloys in electron beam cladding

    SciTech Connect (OSTI)

    Durakov, Vasiliy G.; Dampilon, Bair V. E-mail: gnusov@rambler.ru; Gnyusov, Sergey F. E-mail: gnusov@rambler.ru

    2014-11-14

    The microstructure and properties of the contact CuCr alloy produced by electron-beam cladding have been investigated. The effect of the electron beam cladding parameters and preheating temperature of the base metal on the structure and the properties of the coatings has been determined. The bimodal structure of the cladding coating has been established. The short circuit currents tests have been carried out according to the Weil-Dobke synthetic circuit simulating procedure developed for vacuum circuit breakers (VCB) test in real electric circuits. Test results have shown that the electron beam cladding (EBC) contact material has better breaking capacity than that of commercially fabricated sintered contact material. The application of the technology of electron beam cladding for production of contact material would significantly improve specific characteristics and reliability of vacuum switching equipment.

  4. Apparent critical phenomena in the superionic phase transition of Cu2-xSe

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Kang, Stephen Dongmin; Danilkin, Sergey A.; Aydemir, Umut; Avdeev, Maxim; Studer, Andrew; Snyder, G. Jeffrey

    2016-01-11

    The superionic phase transition ofmore » $${\\mathrm{Cu}}_{2-x}\\mathrm{Se}$$ accompanies drastic changes in transport properties. The Seebeck coefficient increases sharply while the electrical conductivity and thermal diffusivity drops. Such behavior has previously been attributed to critical phenomena under the assumption of a continuous phase transition. However, applying Landau's criteria suggests that the transition should be first order. Using the phase diagram that is consistent with a first order transition, we show that the observed transport properties and heat capacity curves can be accounted for and modeled with good agreement. The apparent critical phenomena is shown to be a result of compositional degree-of-freedom. In conclusion, understanding of the phase transition allows to explain the enhancement in the thermoelectric figure-of-merit that is accompanied with the transition.« less

  5. Cu--Ni--Fe anode for use in aluminum producing electrolytic cell

    DOE Patents [OSTI]

    Bergsma, S. Craig; Brown, Craig W.; Bradford, Donald R; Barnett, Robert J.; Mezner, Michael B.

    2006-07-18

    A method of producing aluminum in an electrolytic cell containing alumina dissolved in an electrolyte, the method comprising the steps of providing a molten salt electrolyte at a temperature of less than 900.degree. C. having alumina dissolved therein in an electrolytic cell having a liner for containing the electrolyte, the liner having a bottom and walls extending upwardly from said bottom. A plurality of non-consumable Cu--Ni--Fe anodes and cathodes are disposed in a vertical direction in the electrolyte, the cathodes having a plate configuration and the anodes having a flat configuration to compliment the cathodes. The anodes contain apertures therethrough to permit flow of electrolyte through the apertures to provide alumina-enriched electrolyte between the anodes and the cathodes. Electrical current is passed through the anodes and through the electrolyte to the cathodes, depositing aluminum at the cathodes and producing gas at the anodes.

  6. Surface Segregation in a PdCu Alloy Hydrogen Separation Membrane

    SciTech Connect (OSTI)

    Miller, J.B.; Matranga, C.S.; Gellman, A.J.

    2007-06-01

    Separation of hydrogen from mixed gas streams is an important step for hydrogen generation technologies, including hydrocarbon reforming and coal/biomass gasification. Dense palladium-based membranes have received significant attention for this application because of palladiums ability to dissociatively adsorb molecular hydrogen at its surface for subsequent transport of hydrogen atoms through its bulk. Alloying palladium with minor components, like copper, has been shown to improve both the membranes structural characteristics and resistance to poisoning of its catalytic surface [1]. Surface segregationa composition difference between the bulk material and its surfaceis common in alloys and can affect important surface processes. Rational design of alloy membranes requires that surface segregation be understood, and possibly controlled. In this work, we examine surface segregation in a polycrystalline Pd70Cu30 hydrogen separation membrane as a function of thermal treatment and adsorption of hydrogen sulfide.

  7. Surface nanostructuring of Ni/Cu foils by femtosecond laser pulses

    SciTech Connect (OSTI)

    Korol'kov, V P; Ionin, Andrei A; Kudryashov, Sergei I; Seleznev, L V; Sinitsyn, D V; Samsonov, R V; Maslii, A I; Medvedev, A Zh; Gol'denberg, B G

    2011-04-30

    This work examines the effect of high-power femtosecond laser pulses on Ni/Cu bilayer foils produced by electrodeposition. We consider nanostructures formed at different laser beam parameters and under different ambient conditions. The surface nanostructures obtained in air and water have mostly the form of quasi-periodic ripples with a characteristic period of 400 - 450 and 370 - 390 nm, respectively, at a laser wavelength of 744 nm, whereas the nanostructures produced in ethanol and benzine have the form of spikes, typically spaced 400 - 700 nm apart. Femtosecond laser nanostructuring of metals is for the first time proposed, and experimentally tested, as a viable approach to producing anti-reflective coatings on the surface of polymer replicas. (laser nanotechnologies)

  8. Co-Evaporated Cu2ZnSnSe4 Films and Devices

    SciTech Connect (OSTI)

    Repins, I.; Beall, C.; Vora, N.; DeHart, C.; Kuciauskas, D.; Dippo, P.; To, B.; Mann, J.; Hsu, W. C.; Goodrich, A.; Noufi, R.

    2012-06-01

    The use of vacuum co-evaporation to produce Cu2ZnSnSe4 photovoltaic devices with 9.15% total-area efficiency is described. These new results suggest that the early success of the atmospheric techniques for kesterite photovoltaics may be related to the ease with which one can control film composition and volatile phases, rather than a fundamental benefit of atmospheric conditions for film properties. The co-evaporation growth recipe is documented, as is the motivation for various features of the recipe. Characteristics of the resulting kesterite films and devices are shown in scanning electron micrographs, including photoluminescence, current-voltage, and quantum efficiency. Current-voltage curves demonstrate low series resistance without the light-dark cross-over seen in many devices in the literature. Band gap indicated by quantum efficiency and photoluminescence is roughly consistent with that expected from first principles calculation.

  9. Diffusion-Reaction Modeling of Cu Migration in CdTe Solar Devices

    SciTech Connect (OSTI)

    Guo, Da; Brinkman, Daniel; Fang, Tian; Akis, Richard; Sankin, Igor; Vasileska, Dragica; Ringhofer, Christian

    2015-09-04

    In this work, we report on development of one-dimensional (1D) finite-difference and two-dimensional (2D) finite-element diffusion-reaction simulators to investigate mechanisms behind Cu-related metastabilities observed in CdTe solar cells [1]. The evolution of CdTe solar cells performance has been studied as a function of stress time in response to the evolution of associated acceptor and donor states. To achieve such capability, the simu-lators solve reaction-diffusion equations for the defect states in time-space domain self-consistently with the free carrier transport. Re-sults of 1-D and 2-D simulations have been compared to verify the accuracy of solutions.

  10. Factors affecting initial permeability of Co-substituted Ni-Zn-Cu ferrites

    SciTech Connect (OSTI)

    Byun, T.Y.; Byeon, S.C.; Hong, K.S.; Kim, C.K.

    1999-09-01

    Iron deficient compositions of (Ni{sub 0.2}Cu{sub 0.2}Zn{sub 0.6}){sub 1.02{minus}x}Co{sub x}Fe{sub 1.98}O{sub 4} (0 {le} x {le} 0.05) were prepared to investigate their initial permeability dependence on cobalt contents. Extrinsic factors such as grain size and sintered density change little in samples sintered at 900 C, so their effects on permeability can be neglected. Intrinsic factors such as saturation magnetization, magnetocrystalline anisotropy (K{sub 1}) and magnetoelastic anisotropy (K{sub {sigma}}) can not account for the variation of initial permeability with Co content. Measurement of thermoelectric power shows that the concentration of cation vacancies increases with Co content. Therefore, the local induced anisotropy increases by the ordering of Co ions cia increased cation vacancy concentration. This increase in induced anisotropy results in the decrease of initial permeability.

  11. Three-dimensional Dendritic Needle Network model with application to Al-Cu directional solidification experiments

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Tourret, D.; Karma, A.; Clarke, A. J.; Gibbs, P. J.; Imhoff, S. D.

    2015-06-11

    We present a three-dimensional (3D) extension of a previously proposed multi-scale Dendritic Needle Network (DNN) approach for the growth of complex dendritic microstructures. Using a new formulation of the DNN dynamics equations for dendritic paraboloid-branches of a given thickness, one can directly extend the DNN approach to 3D modeling. We validate this new formulation against known scaling laws and analytical solutions that describe the early transient and steady-state growth regimes, respectively. Finally, we compare the predictions of the model to in situ X-ray imaging of Al-Cu alloy solidification experiments. The comparison shows a very good quantitative agreement between 3D simulationsmore » and thin sample experiments. It also highlights the importance of full 3D modeling to accurately predict the primary dendrite arm spacing that is significantly over-estimated by 2D simulations.« less

  12. Physicochemical investigations of carbon nanofiber supported Cu/ZrO{sub 2} catalyst

    SciTech Connect (OSTI)

    Din, Israf Ud E-mail: maizats@petronas.com.my; Shaharun, Maizatul S. E-mail: maizats@petronas.com.my; Subbarao, Duvvuri; Naeem, A.

    2014-10-24

    Zirconia-promoted copper/carbon nanofiber catalysts (Cu?ZrO{sub 2}/CNF) were prepared by the sequential deposition precipitation method. The Herringbone type of carbon nanofiber GNF-100 (Graphite nanofiber) was used as a catalyst support. Carbon nanofiber was oxidized to (CNF-O) with 5% and 65 % concentration of nitric acid (HNO{sub 3}). The CNF activated with 5% HNO{sub 3} produced higher surface area which is 155 m{sup 2}/g. The catalyst was characterized by X-ray Diffraction (XRD), Fourier Transform Infra-Red (FTIR) and N{sub 2} adsorption-desorption. The results showed that increase of HNO{sub 3} concentration reduced the surface area and porosity of the catalyst.

  13. Reduced Cu(InGa)Se2 Thickness in Solar Cells Using a Superstrate Configuration

    SciTech Connect (OSTI)

    Shafarman, William N.

    2015-03-30

    This project by the Institute of Energy Conversion (IEC) and the Department of Electrical and Computer Engineering at the University of Delaware sought to develop the technology and underlying science to enable reduced cost of Cu(InGa)Se2 manufacturing by reducing the thickness of the Cu(InGa)Se2 absorber layer by half compared to typical production. The approach to achieve this was to use the superstrate cell configuration in which light is incident on the cell through the glass. This structure facilitates optical enhancement approaches needed to achieve high efficiency with Cu(InGa)Se2 thicknesses less than 1 µm. The primary objective was to demonstrate a Cu(InGa)Se2 cell with absorber thickness 0.5 - 0.7 µm and 17% efficiency, along with a quantitative loss analysis to define a pathway to 20% efficiency. Additional objectives were the development of stable TCO and buffer layers or contact layers to withstand the Cu(InGa)Se2 deposition temperature and of advanced optical enhancement methods. The underlying fundamental science needed to effectively transition these outcomes to large scale was addressed by extensive materials and device characterization and by development of comprehensive optical models. Two different superstrate configurations have been investigated. A frontwall cell is illuminated through the glass to the primary front junction of the device. This configuration has been used for previous efforts on superstrate Cu(InGa)Se2 but performance has been limited by interdiffusion or reaction with CdS or other buffer layers. In this project, several approaches to overcome these limitations were explored using CdS, ZnO and ZnSe buffer layers. In each case, mechanisms that limit device performance were identified using detailed characterization of the materials and junctions. Due to the junction formation difficulties, efforts were concentrated on a new backwall configuration in which light is incident through the substrate into the back of the absorber layer. The primary junction is then formed after Cu(InGa)Se2 deposition. This allows the potential benefits of superstrate cells for optical enhancement while maintaining processing advantages of the substrate configuration and avoiding the harmful effects of high temperature deposition on p-n junction formation. Backwall devices have outperformed substrate cells at absorber thicknesses of 0.1-0.5 µm through enhanced JSC due to easy incorporation of a Ag reflector and, with light incident on the absorber, the elimination of parasitic absorption in the CdS buffer. An efficiency of 9.7% has been achieved for a backwall Cu(InGa)Se2 device with absorber thickness ~0.4 μm. A critical achievement that enabled implementation of the backwall cell was the development of a transparent back contact using MoO3 or WO3. Processes for controlled deposition of each material by reactive rf sputtering from metal targets were developed. These contacts have wide bandgaps making them well-suited for application as contacts for backwall devices as well as potential use in bifacial cells and as the top cell of tandem CuInSe2-based devices. Optical enhancement will be critical for further improvements. Wet chemical texturing of ZnO films has been developed for a simple, low cost light-trapping scheme for backwall superstrate devices to enhance long wavelength quantum efficiency. An aqueous oxalic acid etch was developed and found to strongly texture sputtered ZnO with high haze ≈ 0.9 observed across the whole spectrum. And finally, advanced optical models have been developed to assist the characterization and optimization of Cu(InGa)Se2 cells with thin absorbers

  14. Ag-Pd-Cu alloy inserted transparent indium tin oxide electrodes for organic solar cells

    SciTech Connect (OSTI)

    Kim, Hyo-Joong; Seo, Ki-Won; Kim, Han-Ki; Noh, Yong-Jin; Na, Seok-In

    2014-09-01

    The authors report on the characteristics of Ag-Pd-Cu (APC) alloy-inserted indium tin oxide (ITO) films sputtered on a glass substrate at room temperature for application as transparent anodes in organic solar cells (OSCs). The effect of the APC interlayer thickness on the electrical, optical, structural, and morphological properties of the ITO/APC/ITO multilayer were investigated and compared to those of ITO/Ag/ITO multilayer electrodes. At the optimized APC thickness of 8 nm, the ITO/APC/ITO multilayer exhibited a resistivity of 8.55 × 10{sup −5} Ω cm, an optical transmittance of 82.63%, and a figure-of-merit value of 13.54 × 10{sup −3} Ω{sup −1}, comparable to those of the ITO/Ag/ITO multilayer. Unlike the ITO/Ag/ITO multilayer, agglomeration of the metal interlayer was effectively relieved with APC interlayer due to existence of Pd and Cu elements in the thin region of the APC interlayer. The OSCs fabricated on the ITO/APC/ITO multilayer showed higher power conversion efficiency than that of OSCs prepared on the ITO/Ag/ITO multilayer below 10 nm due to the flatness of the APC layer. The improved performance of the OSCs with ITO/APC/ITO multilayer electrodes indicates that the APC alloy interlayer prevents the agglomeration of the Ag-based metal interlayer and can decrease the thickness of the metal interlayer in the oxide-metal-oxide multilayer of high-performance OSCs.

  15. From nGy to MGy - New dosimetry with LiF:Mg,Cu,P thermoluminescence detectors

    SciTech Connect (OSTI)

    Obryk, Barbara

    2013-05-06

    One of the well known advantages of thermoluminescence (TL) detectors made of lithium fluoride doped with magnesium, copper and phosphorus (LiF:Mg,Cu,P) is their very high sensitivity to ionizing radiation. LiF:Mg,Cu,P detectors enable measurements of radiation doses from tens of nanograys up to a few kilograys, when the total saturation of the signal of the so-called main dosimetric peak occurs. Only recently, unprecedented high-temperature emission of LiF detectors heated to temperatures up to 600 Degree-Sign C, was observed after exposures to radiation doses ranging from 1 kGy to 1 MGy. For quantification of the glow-curve shape changes of LiF:Mg,Cu,P detectors in this range of doses and determination of the absorbed dose, the Ultra-High Temperature Ratio coefficient (UHTR) was defined. This newly established dosimetric method was tested in a range of radiation qualities, such as gamma radiation, electron and proton beams, thermal neutron fields and high-energy mixed fields around the SPS and PS accelerators at CERN. The new method for ultra-high dose range monitoring with a single LiF:Mg,Cu,P detector, which is capable of covering at least twelve orders of magnitude of doses, can be used for dosimetry at high energy accelerators, thermonuclear fusion technology facilities and has great potential for accident dosimetry in particular. A number of dosimetric sets with LiF:Mg,Cu,P detectors are currently installed around the LHC at CERN.

  16. Cu{sup II} coordination polymers based on 5-methoxyisophthalate and flexible N-donor ligands: Structures and magnetic properties

    SciTech Connect (OSTI)

    Chang, Xin-Hong; Qin, Jian-Hua; Ma, Lu-Fang; Wang, Li-Ya

    2014-04-01

    Three Cu{sup II} coordination polymers, ([Cu{sub 2}(CH{sub 3}O-ip){sub 2}(bmib)]){sub n} (1), ([Cu{sub 2}(CH{sub 3}O-ip){sub 2}(bmib){sub 2}]){sub n} (2) and ([Cu(CH{sub 3}O-ip)(bbip)]?2H{sub 2}O){sub n} (3) (CH{sub 3}O-H{sub 2}ip is 5-methoxyisophthalic acid, bmib is 1,4-bis(2-methylimidazol-1-yl)butane and bbip is 1,3-bis(1H-benzimidazolyl)propane), have been synthesized by hydrothermal methods. Complexes 13 were structurally characterized by elemental analysis, infrared (IR) spectra and X-ray single-crystal diffraction. Complex 1 shows a 3D six-connected self-penetrating network based on paddlewheel secondary building units. Complex 2 has a 3-fold interpenetrating 3D diamond framework. Complex 3 possesses a 1D tube-like chain. Thermo-gravimetric and magnetic properties of 13 were also investigated. - Graphical abstract: Structures and magnetic properties of copper(II) coordination polymers constructed from 5-methoxyisophthalate linker and two flexible N-donor ancillary ligands. Three copper(II) coordination polymers with 5-methoxyisophthalate and two related flexible N-donor ancillary ligands have been synthesized and structurally characterized. Moreover, thermal behaviors and magnetic properties of these complexes have also been investigated. - Highlights: Three Cu(II) coordination polymers were synthesized. The conformations of N-donor ligands and pH value have an effect on the final structures. The magnetic properties of 13 have been investigated.

  17. Conductance and spin-filter effects of oxygen-incorporated Au, Cu, and Fe single-atom chains

    SciTech Connect (OSTI)

    Zheng, Xiaolong; Xie, Yi-Qun Ye, Xiang; Ke, San-Huang

    2015-01-28

    We studied the spin-polarized electron transport in oxygen-incorporated Au, Cu, and Fe single-atom chains (SACs) by first-principles calculations. We first investigated the mechanism responsible for the low conductance (<1G{sub 0}) of the Au and Cu SACs in an oxygen environment reported in recent experiments. We found that for the Au SACs, the low conductance plateau around 0.6G{sub 0} can be attributed to a distorted chain doped with a single oxygen atom, while the 0.1G{sub 0} conductance comes from a linear chain incorporated with an oxygen molecule and is caused by an antibonding state formed by oxygen's occupied frontier orbital with d{sub z} orbitals of adjacent Au atoms. For the Cu SACs, the conductance about 0.3G{sub 0} is ascribed to a special configuration that contains Cu and O atoms in an alternating sequence. This exhibits an even-odd conductance oscillation with an amplitude of ∼0.1G{sub 0}. In contrast, for the alternating Fe-O SACs, conductance overall decreases with an increase in O atoms and it approaches nearly zero for the chain with more than four O atoms. While the Cu-O SACs behave as perfect spin filters for one spin channel due to the half metallic nature, the Fe-O SACs can serve as perfect spin filters for two spin channels depending on the polarity of the applied gate voltage.

  18. Transformation behavior and shape memory characteristics of thermo-mechanically treated Ti(45?x)Ni5CuxV (at%) alloys

    SciTech Connect (OSTI)

    Jang, Jae-young; Chun, Su-jin; Choi, Eunsoo; Liu, Yinong; Yang, Hong; Nam, Tae-hyun

    2012-10-15

    Transformation behavior, shape memory characteristics and superelasticity of thermo-mechanically treated Ti(45?x)Ni5CuxV (at%) (x = 0.52.0) alloys were investigated by means of differential scanning calorimetry, transmission electron microscopy, X-ray diffractions, thermal cycling tests under constant load and tensile tests. The B2B19? transformation occurred when V content was 0.5 at%, above which the B2B19B19? transformation occurred. The B2B19 transformation was not separated clearly from the B19B19? transformation. Thermo-mechanically treated Ti(45?x)Ni5CuxV alloys showed perfect shape memory effect and transformation hysteresis(?T) of Ti43.5Ni5.0Cu1.5V and Ti43.0Ni5.0Cu2.0V alloys was about 9 K which was much smaller than that of a Ti44.5Ni5.0Cu0.5V alloy(23.3 K). More than 90% of superelastic recovery ratio was observed in all specimens and transformation hysteresis (??) of a Ti44.5Ni5.0Cu0.5V alloy was about 70 MPa, which was much larger than that of a Ti43.0Ni5.0Cu2.0V alloy (35 MPa).

  19. Electronic structure of antifluorite Cu{sub 2}X (X = S, Se, Te) within the modified Becke-Johnson potential plus an on-site Coulomb U

    SciTech Connect (OSTI)

    Zhang, Yubo; Wang, Youwei; Xi, Lili; Qiu, Ruihao; Shi, Xun; Zhang, Peihong E-mail: pzhang3@buffalo.edu; Beijing Computational Science Research Center, Beijing 100084 ; Zhang, Wenqing E-mail: pzhang3@buffalo.edu; School of Chemistry and Chemical Engineering, and Sate Key Laboratory of Coordination Chemistry, Nanjing University, Jiangsu 210093

    2014-02-21

    The traditional photon absorbers Cu{sub 2?x}X (X = S, Se, and Te) have regained significant research attention in the search of earth-abundant photovoltaic materials. These moderate- and narrow-gap materials have also been shown to exhibit excellent thermoelectric properties recently. However, semimetallic band structures with inverted band orderings are predicted for antifluorite structure Cu{sub 2}X using density functional theory with the local density approximation or the generalized gradient approximation. We find that semiconducting band structures and normal band orderings can be obtained using the modified Becke-Johnson potential plus an on-site Coulomb U (the mBJ+U approach), which is consistent with our earlier finding for diamond-like Cu-based multinary semiconductors [Y. Zhang, J. Zhang, W. Gao, T. A. Abtew, Y. Wang, P. Zhang, and W. Zhang, J. Chem. Phys. 139, 184706 (2013)]. The trend of the chemical bonding of Cu{sub 2}X is analyzed, which shows that the positions of the valence band maximum and conduction band minimum are strongly affected by the inter-site pd and intra-site sp hybridizations, respectively. The calculated gaps of Cu{sub 2}S and Cu{sub 2}Se still seem to be underestimated compared with experimental results. We also discuss the effects of different structural phases and Cu disordering and deficiency on the bandgaps of these materials.

  20. CuCo2O4 ORR/OER Bi-functional catalyst: Influence of synthetic approach on performance

    SciTech Connect (OSTI)

    Serov, Alexey; Andersen, Nalin I.; Roy, Aaron J.; Matanovic, Ivana; Artyushkova, Kateryna; Atanassov, Plamen

    2015-02-07

    A series of CuCo2O4 catalysts were synthesized by pore forming, sol-gel, spray pyrolysis and sacrificial support methods. Catalysts were characterized by XRD, SEM, XPS and BET techniques. The electrochemical activity for the oxygen reduction and oxygen evolution reactions (ORR and OER) was evaluated in alkaline media by RRDE. Density Functional Theory was used to identify two different types of active sites responsible for ORR/OER activity of CuCo2O4 and it was found that CuCo2O4 can activate the O-O bond by binding molecular oxygen in bridging positions between Co or Co and Cu atoms. It was found that the sacrificial support method (SSM) catalyst has the highest performance in both ORR and OER and has the highest content of phase-pure CuCo2O4. It was shown that the presence of CuO significantly decreases the activity in oxygen reduction and oxygen evolution reactions. As a result, the half-wave potential (E1/2) of CuCo2O4-SSM was found as 0.8 V, making this material a state-of-the-art, unsupported oxide catalyst.

  1. Hybrid CuO/SnO{sub 2} nanocomposites: Towards cost-effective and high performance binder free lithium ion batteries anode materials

    SciTech Connect (OSTI)

    Xing, G. Z.; Wang, Y.; Wong, J. I.; Shi, Y. M.; Huang, Z. X.; Yang, H. Y.; Li, S.

    2014-10-06

    Hybrid CuO/SnO{sub 2} nanocomposites are synthesized by a facile thermal annealing method on Cu foils. Compared to pristine CuO and SnO{sub 2} nanostructures, hybrid CuO/SnO{sub 2} nanocomposites exhibit the enhanced electrochemical performances as the anode material of lithium ion batteries (LIBs) with high specific capacity and excellent rate capability. The binder free CuO/SnO{sub 2} nanocomposites deliver a specific capacity of 718 mA h g{sup ?1} at a current density of 500?mA g{sup ?1} even after 200 cycles. The enhanced electrochemical performances are attributed to the synergistic effect between SnO{sub 2} nanoparticles and CuO nanoarchitectures. Such hybrid CuO/SnO{sub 2} nanocomposites could open up a new route for the development of next-generation high-performance and cost-effective binder free anode material of LIBs for mass production.

  2. Oxidation of elemental mercury vapor over gamma-Al2O3 supported CuCl2 catalyst for mercury emissions control

    SciTech Connect (OSTI)

    Liu, Zhouyang; Liu, Xin; Lee, Joo-Youp; Bolin, Trudy B.

    2015-09-01

    In our previous studies, CuCl2 demonstrated excellent Hg(0) oxidation capability and holds potential for Hg(0) oxidation in coal-fired power plants. In this study, the properties and performances of CuCl2 supported onto gamma-Al2O3 with high surface area were investigated. From various characterization techniques using XPS, XAFS, XRD, TPR, SEM and TGA, the existence of multiple copper species was identified. At low CuCl2 loadings, CuCl2 forms copper aluminate species with gamma-Al2O3 and is inactive for Hg(0) oxidation. At high loadings, amorphous CuCl2 forms onto the gamma-Al2O3 surface, working as a redox catalyst for Hg(0) oxidation by consuming Cl to be converted into CuCl and then being regenerated back into CuCl2 in the presence of O-2 and HCl gases. The 10%(wt) CuCl2/gamma-Al2O3 catalyst showed excellent Hg(0) oxidation performance and SO2 resistance at 140 degrees C under simulated flue gas conditions containing 6%(v) O-2 and 10 ppmv HCl. The oxidized Hg(0) in the form of HgCl2 has a high solubility in water and can be easily captured by other air pollution control systems such as wet scrubbers in coal-fired power plants. The CuCl2/gamma-Al2O3 catalyst can be used as a low temperature Hg(0) oxidation catalyst. (C) 2015 Elsevier B.V. All rights reserved.

  3. Effect of argon gas flow rate on properties of film electrodes prepared by thermal vacuum evaporation from synthesized Cu{sub 2}SnSe{sub 3} source

    SciTech Connect (OSTI)

    Sabli, Nordin; Talib, Zainal Abidin; Yunus, Wan Mahmood Mat; Zainal, Zulkarnain; Hilal, Hikmat S.; Fujii, Masatoshi

    2014-03-05

    This work describes a new technique to enhance photoresponse of metal chalcogenide-based semiconductor film electrodes deposited by thermal vacuum evaporation under argon gas flow from synthesized Cu{sub 2}SnSe{sub 3} sources. SnSe formation with Cu-doped was obtained under higher argon gas flow rate (V{sub A} = 25 cm{sup 3}/min). Higher value of photoresponse was observed for films deposited under V{sub A} = 25 cm{sup 3}/min which was 9.1%. This finding indicates that Cu atoms inside the SnSe film were important to increase carrier concentrations that promote higher photoresponse.

  4. Neutron-scattering evidence for a periodically modulated superconducting phase in the underdoped cuprate La1.905Ba0.095CuO4

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Xu, Zhijun; Stock, C.; Chi, Songxue; Kolesnikov, A. I.; Xu, Guangyong I.; Gu, Genda; Tranquada, J. M.

    2014-10-01

    The role of antiferromagnetic spin correlations in high-temperature superconductors remains a matter of debate. We present inelastic neutron-scattering evidence that gapless spin fluctuations coexist with superconductivity in La1.905Ba0.095CuO4. Furthermore, we observe that both the low-energy magnetic spectral weight and the spin incommensurability are enhanced with the onset of superconducting correlations. We propose that the coexistence occurs through intertwining of spatial modulations of the pair wave function and the antiferromagnetic correlations. This proposal is also directly relevant to sufficiently underdoped La2-xSrxCuO4 and YBa2Cu3O6+x.

  5. High field magnetotransport and point contact Andreev reflection measurements on CuCr{sub 2}Se{sub 4} and CuCr{sub 2}Se{sub 3}BrDegenerate magnetic semiconductor single crystals

    SciTech Connect (OSTI)

    Borisov, K. Coey, J. M. D.; Stamenov, P.; Alaria, J.

    2014-05-07

    Single crystals of the metallically degenerate fully magnetic semiconductors CuCr{sub 2}Se{sub 4} and CuCr{sub 2}Se{sub 3}Br have been prepared by the Chemical Vapour Transport method, using either Se or Br as transport agents. The high-quality, millimetre-sized, octahedrally faceted, needle- and platelet-shaped crystals are characterised by means of high field magnetotransport (?{sub 0}H? 14?T) and Point Contact Andreev Reflection. The relatively high spin polarisation observed |P|>0.56, together with the relatively low minority carrier effective mass of 0.25 m{sub e}, and long scattering time 10{sup ?13}?s, could poise these materials for integration in low- and close-to-room temperature minority injection bipolar heterojunction transistor demonstrations.

  6. Systematic investigation of electronic structure in BEDT-TTF based organic superconductors with Tc above 10 K; [kappa]-(BEDT-TTF)[sub 2]X (X = Cu(NCS)[sub 2], Cu[N(CN)[sub 2

    SciTech Connect (OSTI)

    Nakamura, Toshikazu; Nobutoki, Tomoko; Miyamoto, Masao; Tsubokura, Yuichi; Tsuchiya, Ryota; Takahashi, Toshihiro ); Kanoda, Kazushi ); Saito, Gunzi )

    1994-06-01

    The electronic structure of the title superconductors has been investigated by electrical resistivity, complex susceptibility, and electron paramagnetic resonance (EPR) measurements. The superconducting properties (pressure dependence of Tc, magnetic penetration depth, upper critical field, and so on) of these three salts are similar to each other, while transport properties in the normal state have shown a large variety in the temperature dependence. In order to clarify the electronic structure in the normal state, the EPR parameters, the spin susceptibility ([Chi][sub spin]), and the linewidth ([Delta]H[sub pp]), are compared. An anomalous temperature dependence of the g-value has been observed below 150 K in the Cu(NCS)[sub 2] and Cu(CN)[N(CN)[sub 2

  7. Alternative fabrication techniques for high-efficiency CuInSe{sub 2} and CuInSe{sub 2}-alloy films and cells. Final subcontract report, 1 March 1990--31 August 1992

    SciTech Connect (OSTI)

    Rockett, A.; Yang, L.C.; Kenshole, G.; Banda, E.; Feen, A.

    1994-07-01

    Work performed during the course of this subcontract has led to improved CuInSe{sub 2} (CIS) processing techniques and materials resulting in improved solar cell performance (up to 10% active area efficiency) based on a thick conductive evaporated CdS window layer and an indium-tin-oxide transparent conductor. Modeling of the device performance has indicated that an optimal CdS thickness should exist if pinholes occur in the CIS layer (for example, due to adhesion failures) leading to shunts between the CdS and the back contact. Pinholes in the CIS layer have been dramatically reduced by the use of a Cu-Mo two-phase back contact metallization resulting from significant increases in adhesion between the CIS and the back contact. Controlled leaching of the Cu from the back contact apparently contributes to this improvement without degradation of the solar cells. Finally, CIS has been grown epitaxially on GaAs. Preliminary results suggest explanations for the morphology and defect structures of polycrystalline layers used in devices as well as indicating the general mechanism for growth of CIS by vapor phase methods.

  8. Magnetic Nature of the 500 meV peak in La2−xSrxCuO4 Observed with Resonant Inelastic X-ray Scattering at the Cu K-edge

    SciTech Connect (OSTI)

    Hill, J.P.; Ellis, D.S.; Kim, J.; Wakimoto, S.; Birgeneau, R.J.; Shvyd’ko, Y.; Casa, D.; Gog, T.; Ishii, K.; Ikeuchi, K.; Paramekanti, A.; Kim, Y.-J.

    2010-02-15

    We present a comprehensive study of the temperature and doping dependence of the 500 meV peak observed at q = ({pi},0) in resonant inelastic x-ray scattering (RIXS) experiments on La{sub 2}CuO{sub 4}. The intensity of this peak persists above the Neel temperature (T{sub N} = 320 K), but decreases gradually with increasing temperature, reaching zero at around T = 500 K. The peak energy decreases with temperature in close quantitative accord with the behavior of the two-magnon B{sub 1g} Raman peak in La{sub 2}CuO{sub 4} and, with suitable rescaling, agrees with the Raman peak shifts in EuBa{sub 2}Cu{sub 3}O{sub 6} and K{sub 2}NiF{sub 4}. The overall dispersion of this excitation in the Brillouin zone is found to be in agreement with theoretical calculations for a two-magnon excitation. Upon doping, the peak intensity decreases analogous to the Raman mode intensity and appears to track the doping dependence of the spin-correlation length. Taken together, these observations strongly suggest that the 500 meV mode is magnetic in character and is likely a two-magnon excitation.

  9. Lattice instabilities in heavy fermion superconductors. [CeCu/sub 2/Si/sub 2/; CeAl/sub 3/; CeCu/sub 6/; UBe/sub 13/; UPt/sub 3/

    SciTech Connect (OSTI)

    Wohlleben, D.

    1987-01-01

    This paper shows that while in nonsuperconducting HF systems such as CeCu/sub 6/, CeAl/sub 3/ and stoichiometric CeCu/sub 2/Si/sub 2/, the large electronic ..gamma.. is due to a very narrow f band, in the three HF superconductors UBe/sub 13/, UPt/sub 3/ and nonstochiometric CeCu/sub 2/Si/sub 2/, it is not. The f band of these systems, as measured by their response to magnetic fields in three different ways, is much wider than suggested by the large ..gamma... According to their actual f band width, the HF superconductors belong into the Bantam Fermion class. It is argued that most of the large ..gamma.. of the HF superconductors is not of electronic origin and that it is instead caused by the precursor of a martensitic phase transition of the lattice or by a crystallographic phase mixture, i.e., that it is due to the displacive degrees of freedom. This suggests that the superconductivity of all three HF superconductors is caused by some special, low energy phonons rather than by a narrow f band. 52 refs., 4 figs., 3 tabs.

  10. Magnetization reversal of a Nd-Cu-infiltrated Nd-Fe-B nanocrystalline magnet observed with small-angle neutron scattering

    SciTech Connect (OSTI)

    Saito, Kotaro Ono, Kanta; Ueno, Tetsuro; Yano, Masao; Shoji, Tetsuya; Sakuma, Noritsugu; Manabe, Akira; Kato, Akira; Harada, Masashi; Keiderling, Uwe

    2015-05-07

    The magnetization reversal process of Nd-Fe-B nanocrystalline magnets infiltrated with Nd-Cu alloy was examined using small-angle neutron scattering (SANS). The magnetic-field dependence of SANS intensity revealed a qualitative difference between Nd-Cu-infiltrated samples and as-deformed samples. Insufficient magnetic isolation along the direction perpendicular to the nominal c-axis is expected from comparable SANS intensities for different ranges of q values along this direction. For small q values near the coercivity field, Nd-Cu-infiltrated samples show a noticeable reduction in SANS intensity along the nominal c-axis, which is parallel to the external magnetic field. This indicates less spatial fluctuation of magnetic moments in Nd-Cu-infiltrated samples, owing to magnetically isolated Nd{sub 2}Fe{sub 14}B grains.

  11. Generation of spin currents in the skyrmion phase of a helimagnetic insulator Cu{sub 2}OSeO{sub 3}

    SciTech Connect (OSTI)

    Hirobe, Daichi Shiomi, Yuki; Shimada, Yuhki; Ohe, Jun-ichiro; Saitoh, Eiji

    2015-02-07

    We report spin-current generation related to skyrmion dynamics resonantly excited by a microwave in a helimagnetic insulator Cu{sub 2}OSeO{sub 3}. A Pt layer was fabricated on Cu{sub 2}OSeO{sub 3} and voltage in the Pt layer was measured upon magnetic upon magnetic resonance of Cu{sub 2}OSeO{sub 3} to electrically detect injected spin currents via the inverse spin Hall effect (ISHE) in Pt. We found that ISHE-induced electromotive forces appear in the skyrmion phase of Cu{sub 2}OSeO{sub 3} as well as in the ferrimagnetic phase, which shows that magnetic skyrmions can contribute to the spin pumping effect.

  12. Effect of internal noise on the oscillation of N{sub 2}O decomposition over Cu-ZSM-5 zeolites using a stochastic description

    SciTech Connect (OSTI)

    Liu, Fuliang; Li, Yaping Sun, Xiaoming

    2014-01-28

    When considering stochastic oscillations of heterogeneous catalyst systems, most researches have focused on the surface of a metal or its oxide catalysts, but there have been few studies on porous catalysts. In this work, the effects of internal noise on oscillations of N{sub 2}O decomposition over Cu-ZSM-5 zeolites are investigated, using the chemical Langevin equation and a mesoscopic stochastic model. Considering that Cu-ZSM-5 particles are finely divided particles, the number of Cu ions (N{sub s}) is proportional to the particle size at a certain Cu/Al, and the internal noise is inversely proportional to N{sub s}. Stochastic oscillations can be observed outside the deterministic oscillatory region. Furthermore, the performance of the oscillation characterized by the signal-to-noise ratio has a maximum within the optimal size range of 48 nm. This suggests that a nanometer-sized zeolite may be best for oscillations.

  13. Efficient enhancement of hydrogen production by Ag/Cu{sub 2}O/ZnO tandem triple-junction photoelectrochemical cell

    SciTech Connect (OSTI)

    Liu, Ying; Ren, Feng Chen, Chao; Liu, Chang; Xing, Zhuo; Liu, Dan; Xiao, Xiangheng; Wu, Wei; Zheng, Xudong; Liu, Yichao; Jiang, Changzhong; Shen, Shaohua; Fu, Yanming

    2015-03-23

    Highly efficient semiconductor photoelectrodes for solar hydrogen production through photocatalytic water splitting are a promising and challenge solution to solve the energy problems. In this work, Ag/Cu{sub 2}O/ZnO tandem triple-junction photoelectrode was designed and prepared. An increase of 11 times of photocurrent is achieved in the Ag/Cu{sub 2}O/ZnO photoelectrode comparing to that of the Cu{sub 2}O film. The high performance of the Ag/Cu{sub 2}O/ZnO film is due to the optimized design of the tandem triple-junction structure, where the localized surface Plasmon resonance of Ag and the hetero-junctions efficiently absorb solar energy, produce, and separate electron-hole pairs in the photocathode.

  14. Nuclear matter effects on J/ψ production in asymmetric Cu + Au collisions at \\(\\sqrt{s_{\\mathrm{NN}}} = 200\\) GeV

    SciTech Connect (OSTI)

    Adare, A.; Aidala, C.; Ajitanand, N. N.; Akiba, Y.; Akimoto, R.; Alexander, J.; Alfred, M.; Aoki, K.; Apadula, N.; Aramaki, Y.; Asano, H.; Atomssa, E. T.; Awes, T. C.; Azmoun, B.; Babintsev, V.; Bai, M.; Bai, X.; Bandara, N. S.; Bannier, B.; Barish, K. N.; Bathe, S.; Baublis, V.; Baumann, C.; Baumgart, S.; Bazilevsky, A.; Beaumier, M.; Beckman, S.; Belmont, R.; Berdnikov, A.; Berdnikov, Y.; Bing, X.; Black, D.; Blau, D. S.; Bok, J. S.; Boyle, K.; Brooks, M. L.; Bryslawskyj, J.; Buesching, H.; Bumazhnov, V.; Butsyk, S.; Campbell, S.; Chen, C. -H.; Chi, C. Y.; Chiu, M.; Choi, I. J.; Choi, J. B.; Choi, S.; Christiansen, P.; Chujo, T.; Cianciolo, V.; Citron, Z.; Cole, B. A.; Cronin, N.; Crossette, N.; Csanád, M.; Csörgő, T.; Datta, A.; Daugherity, M. S.; David, G.; DeBlasio, K.; Dehmelt, K.; Denisov, A.; Deshpande, A.; Desmond, E. J.; Ding, L.; Dion, A.; Do, J. H.; Drapier, O.; Drees, A.; Drees, K. A.; Durham, J. M.; Durum, A.; D'Orazio, L.; Engelmore, T.; Enokizono, A.; En'yo, H.; Esumi, S.; Eyser, K. O.; Fadem, B.; Feege, N.; Fields, D. E.; Finger, M.; Finger, M.; Fleuret, F.; Fokin, S. L.; Frantz, J. E.; Franz, A.; Frawley, A. D.; Fukao, Y.; Gainey, K.; Gal, C.; Gallus, P.; Garg, P.; Garishvili, A.; Garishvili, I.; Ge, H.; Giordano, F.; Glenn, A.; Gong, X.; Gonin, M.; Goto, Y.; Granier de Cassagnac, R.; Grau, N.; Greene, S. V.; Grosse Perdekamp, M.; Gu, Y.; Gunji, T.; Guragain, H.; Hachiya, T.; Haggerty, J. S.; Hahn, K. I.; Hamagaki, H.; Han, S. Y.; Hanks, J.; Hasegawa, S.; Hashimoto, K.; Hayano, R.; He, X.; Hemmick, T. K.; Hester, T.; Hill, J. C.; Hollis, R. S.; Homma, K.; Hong, B.; Hoshino, T.; Huang, J.; Huang, S.; Ichihara, T.; Ikeda, Y.; Imai, K.; Imazu, Y.; Inaba, M.; Iordanova, A.; Isenhower, D.; Isinhue, A.; Ivanishchev, D.; Jacak, B. V.; Jeon, S. J.; Jezghani, M.; Jia, J.; Jiang, X.; Johnson, B. M.; Joo, E.; Joo, K. S.; Jouan, D.; Jumper, D. S.; Kamin, J.; Kanda, S.; Kang, B. H.; Kang, J. H.; Kang, J. S.; Kapustinsky, J.; Kawall, D.; Kazantsev, A. V.; Key, J. A.; Khachatryan, V.; Khandai, P. K.; Khanzadeev, A.; Kihara, K.; Kijima, K. M.; Kim, C.; Kim, D. H.; Kim, D. J.; Kim, E. -J.; Kim, H. -J.; Kim, M.; Kim, Y. -J.; Kim, Y. K.; Kistenev, E.; Klatsky, J.; Kleinjan, D.; Kline, P.; Koblesky, T.; Kofarago, M.; Komkov, B.; Koster, J.; Kotchetkov, D.; Kotov, D.; Krizek, F.; Kurita, K.; Kurosawa, M.; Kwon, Y.; Lacey, R.; Lai, Y. S.; Lajoie, J. G.; Lebedev, A.; Lee, D. M.; Lee, G. H.; Lee, J.; Lee, K. B.; Lee, K. S.; Lee, S. H.; Leitch, M. J.; Leitgab, M.; Lewis, B.; Li, X.; Lim, S. H.; Liu, M. X.; Lynch, D.; Maguire, C. F.; Makdisi, Y. I.; Makek, M.; Manion, A.; Manko, V. I.; Mannel, E.; Maruyama, T.; McCumber, M.; McGaughey, P. L.; McGlinchey, D.; McKinney, C.; Meles, A.; Mendoza, M.; Meredith, B.; Miake, Y.; Mibe, T.; Mignerey, A. C.; Miller, A. J.; Milov, A.; Mishra, D. K.; Mitchell, J. T.; Miyasaka, S.; Mizuno, S.; Mohanty, A. K.; Montuenga, P.; Moon, T.; Morrison, D. P.; Moskowitz, M.; Moukhanova, T. V.; Murakami, T.; Murata, J.; Mwai, A.; Nagae, T.; Nagamiya, S.; Nagle, J. L.; Nagy, M. I.; Nakagawa, I.; Nakagomi, H.; Nakamiya, Y.; Nakamura, K. R.; Nakamura, T.; Nakano, K.; Nattrass, C.; Netrakanti, P. K.; Nihashi, M.; Niida, T.; Nouicer, R.; Novak, T.; Novitzky, N.; Nyanin, A. S.; O'Brien, E.; Ogilvie, C. A.; Oide, H.; Okada, K.; Orjuela Koop, J. D.; Oskarsson, A.; Ozaki, H.; Ozawa, K.; Pak, R.; Pantuev, V.; Papavassiliou, V.; Park, I. H.; Park, S.; Park, S. K.; Pate, S. F.; Patel, L.; Patel, M.; Peng, J. -C.; Perepelitsa, D. V.; Perera, G. D. N.; Peressounko, D. Yu.; Perry, J.; Petti, R.; Pinkenburg, C.; Pinson, R.; Pisani, R. P.; Purschke, M. L.; Qu, H.; Rak, J.; Ravinovich, I.; Read, K. F.; Reynolds, D.; Riabov, V.; Riabov, Y.; Richardson, E.; Riveli, N.; Roach, D.; Rolnick, S. D.; Rosati, M.; Rowan, Z.; Rubin, J. G.; Ryu, M. S.; Sahlmueller, B.; Saito, N.; Sakaguchi, T.; Sako, H.; Samsonov, V.; Sarsour, M.; Sato, S.; Sawada, S.; Schaefer, B.; Schmoll, B. K.; Sedgwick, K.; Seele, J.; Seidl, R.; Sekiguchi, Y.; Sen, A.; Seto, R.; Sett, P.; Sexton, A.; Sharma, D.; Shaver, A.; Shein, I.; Shibata, T. -A.; Shigaki, K.; Shimomura, M.; Shoji, K.; Shukla, P.; Sickles, A.; Silva, C. L.; Silvermyr, D.; Singh, B. K.; Singh, C. P.; Singh, V.; Skolnik, M.; Slunečka, M.; Solano, S.; Soltz, R. A.; Sondheim, W. E.; Sorensen, S. P.; Soumya, M.; Sourikova, I. V.; Stankus, P. W.; Steinberg, P.; Stenlund, E.; Stepanov, M.; Ster, A.; Stoll, S. P.; Stone, M. R.; Sugitate, T.; Sukhanov, A.; Sumita, T.; Sun, J.; Sziklai, J.; Takahara, A.; Taketani, A.; Tanida, K.; Tannenbaum, M. J.; Tarafdar, S.; Taranenko, A.; Tennant, E.; Timilsina, A.; Todoroki, T.; Tomášek, M.; Torii, H.; Towell, M.; Towell, R.; Towell, R. S.; Tserruya, I.; van Hecke, H. W.; Vargyas, M.; Vazquez-Zambrano, E.; Veicht, A.; Velkovska, J.; Vértesi, R.; Virius, M.; Vrba, V.; Vznuzdaev, E.; Wang, X. R.; Watanabe, D.; Watanabe, K.; Watanabe, Y.; Watanabe, Y. S.; Wei, F.; Whitaker, S.; Wolin, S.; Woody, C. L.; Wysocki, M.; Xia, B.; Xue, L.; Yalcin, S.; Yamaguchi, Y. L.; Yanovich, A.; Yokkaichi, S.; Yoon, I.; You, Z.; Younus, I.; Yushmanov, I. E.; Zajc, W. A.; Zelenski, A.; Zhou, S.

    2014-12-18

    We report on J/ψ production from asymmetric Cu+Au heavy-ion collisions at \\(\\sqrt{s_{\\mathrm{NN}}} = 200\\) GeV at the Relativistic Heavy Ion Collider at both forward (Cu-going direction) and backward (Au-going direction) rapidities. The nuclear modification of J/ψ yields in Cu+Au collisions in the Au-going direction is found to be comparable to that in Au+Au collisions when plotted as a function of the number of participating nucleons. In the Cu-going direction, J/ψ production shows a stronger suppression. This difference is comparable in magnitude and has the same sign as the difference expected from shadowing effects due to stronger low-x gluon suppression in the larger Au nucleus. Thus, the relative suppression is opposite to that expected from hot nuclear matter dissociation, since a higher energy density is expected in the Au-going direction.

  15. Contribution of ion beam analysis to study the mechanisms of YBaCuO thin films growth and of their oxidation kinetics

    SciTech Connect (OSTI)

    Siejka, J.; Garcia-Lopez, J.

    1996-12-31

    At first a short review of ion beam analysis (IBA) techniques such as Rutherford Backscattering Analysis, Nuclear Reaction Analysis and of their contribution to the determination of composition and structure of YBaCuO thin films is presented. In the second part, IBA contribution to the measurements of oxygen content and mobility in YBaCuO and to elucidate the mechanisms of high temperature in situ growth of thin films are discussed. The emphasis is on the complementarity of IBA, Raman spectroscopy, TEM and XRD techniques to characterize the YBaCuO thin films in correlation with their physical properties. The results show that fully oxygenated YBaCuO thin films are formed in situ during high temperature T {le} 750 C, reactive sputtering. Their room temperature oxygen content and order is determined by oxygen loss and or uptake during the sample cooling conditions. The physical implications of these findings are analyzed.

  16. In situ resonant Raman scattering and reversible photoinduced structural change in YBa{sub 2}Cu{sub 3}O{sub 6+x}

    SciTech Connect (OSTI)

    Osada, Minoru; Kaell, Mikael; Baeckstroem, Joakim; Kakihana, Masato; Andersen, Niels Hessel; Boerjesson, Lars

    2005-06-01

    We report on bidirectional photoswitching associated with the CuO chains in oxygen-deficient YBa{sub 2}Cu{sub 3}O{sub 6+x} single crystals. By varying the wavelength of light polarized along the CuO chains, the material can be reversibly switched between two metastable states characterized by the existence or absence of a specific Raman scattering resonance. A comparison of the spectral efficiencies for this photoswitching with analogous data for the persistent photoconductivity and photoconductivity quenching effects suggests that the two phenomena have the same microscopic origin. We argue that the effects are due to photoinduced Cu-O charge-transfer excitations, which destabilize chains of different length depending on wavelength, and promote the growth of thermally inaccessible oxygen ordering configurations.

  17. Nuclear matter effects on J/? production in asymmetric Cu + Au collisions at \\(\\sqrt{s_{\\mathrm{NN}}} = 200\\) GeV

    SciTech Connect (OSTI)

    Adare, A.; Aidala, C.; Ajitanand, N. N.; Akiba, Y.; Akimoto, R.; Alexander, J.; Alfred, M.; Aoki, K.; Apadula, N.; Aramaki, Y.; Asano, H.; Atomssa, E. T.; Awes, T. C.; Azmoun, B.; Babintsev, V.; Bai, M.; Bai, X.; Bandara, N. S.; Bannier, B.; Barish, K. N.; Bathe, S.; Baublis, V.; Baumann, C.; Baumgart, S.; Bazilevsky, A.; Beaumier, M.; Beckman, S.; Belmont, R.; Berdnikov, A.; Berdnikov, Y.; Bing, X.; Black, D.; Blau, D. S.; Bok, J. S.; Boyle, K.; Brooks, M. L.; Bryslawskyj, J.; Buesching, H.; Bumazhnov, V.; Butsyk, S.; Campbell, S.; Chen, C. -H.; Chi, C. Y.; Chiu, M.; Choi, I. J.; Choi, J. B.; Choi, S.; Christiansen, P.; Chujo, T.; Cianciolo, V.; Citron, Z.; Cole, B. A.; Cronin, N.; Crossette, N.; Csand, M.; Csrg?, T.; Datta, A.; Daugherity, M. S.; David, G.; DeBlasio, K.; Dehmelt, K.; Denisov, A.; Deshpande, A.; Desmond, E. J.; Ding, L.; Dion, A.; Do, J. H.; Drapier, O.; Drees, A.; Drees, K. A.; Durham, J. M.; Durum, A.; D'Orazio, L.; Engelmore, T.; Enokizono, A.; En'yo, H.; Esumi, S.; Eyser, K. O.; Fadem, B.; Feege, N.; Fields, D. E.; Finger, M.; Finger, M.; Fleuret, F.; Fokin, S. L.; Frantz, J. E.; Franz, A.; Frawley, A. D.; Fukao, Y.; Gainey, K.; Gal, C.; Gallus, P.; Garg, P.; Garishvili, A.; Garishvili, I.; Ge, H.; Giordano, F.; Glenn, A.; Gong, X.; Gonin, M.; Goto, Y.; Granier de Cassagnac, R.; Grau, N.; Greene, S. V.; Grosse Perdekamp, M.; Gu, Y.; Gunji, T.; Guragain, H.; Hachiya, T.; Haggerty, J. S.; Hahn, K. I.; Hamagaki, H.; Han, S. Y.; Hanks, J.; Hasegawa, S.; Hashimoto, K.; Hayano, R.; He, X.; Hemmick, T. K.; Hester, T.; Hill, J. C.; Hollis, R. S.; Homma, K.; Hong, B.; Hoshino, T.; Huang, J.; Huang, S.; Ichihara, T.; Ikeda, Y.; Imai, K.; Imazu, Y.; Inaba, M.; Iordanova, A.; Isenhower, D.; Isinhue, A.; Ivanishchev, D.; Jacak, B. V.; Jeon, S. J.; Jezghani, M.; Jia, J.; Jiang, X.; Johnson, B. M.; Joo, E.; Joo, K. S.; Jouan, D.; Jumper, D. S.; Kamin, J.; Kanda, S.; Kang, B. H.; Kang, J. H.; Kang, J. S.; Kapustinsky, J.; Kawall, D.; Kazantsev, A. V.; Key, J. A.; Khachatryan, V.; Khandai, P. K.; Khanzadeev, A.; Kihara, K.; Kijima, K. M.; Kim, C.; Kim, D. H.; Kim, D. J.; Kim, E. -J.; Kim, H. -J.; Kim, M.; Kim, Y. -J.; Kim, Y. K.; Kistenev, E.; Klatsky, J.; Kleinjan, D.; Kline, P.; Koblesky, T.; Kofarago, M.; Komkov, B.; Koster, J.; Kotchetkov, D.; Kotov, D.; Krizek, F.; Kurita, K.; Kurosawa, M.; Kwon, Y.; Lacey, R.; Lai, Y. S.; Lajoie, J. G.; Lebedev, A.; Lee, D. M.; Lee, G. H.; Lee, J.; Lee, K. B.; Lee, K. S.; Lee, S. H.; Leitch, M. J.; Leitgab, M.; Lewis, B.; Li, X.; Lim, S. H.; Liu, M. X.; Lynch, D.; Maguire, C. F.; Makdisi, Y. I.; Makek, M.; Manion, A.; Manko, V. I.; Mannel, E.; Maruyama, T.; McCumber, M.; McGaughey, P. L.; McGlinchey, D.; McKinney, C.; Meles, A.; Mendoza, M.; Meredith, B.; Miake, Y.; Mibe, T.; Mignerey, A. C.; Miller, A. J.; Milov, A.; Mishra, D. K.; Mitchell, J. T.; Miyasaka, S.; Mizuno, S.; Mohanty, A. K.; Montuenga, P.; Moon, T.; Morrison, D. P.; Moskowitz, M.; Moukhanova, T. V.; Murakami, T.; Murata, J.; Mwai, A.; Nagae, T.; Nagamiya, S.; Nagle, J. L.; Nagy, M. I.; Nakagawa, I.; Nakagomi, H.; Nakamiya, Y.; Nakamura, K. R.; Nakamura, T.; Nakano, K.; Nattrass, C.; Netrakanti, P. K.; Nihashi, M.; Niida, T.; Nouicer, R.; Novak, T.; Novitzky, N.; Nyanin, A. S.; O'Brien, E.; Ogilvie, C. A.; Oide, H.; Okada, K.; Orjuela Koop, J. D.; Oskarsson, A.; Ozaki, H.; Ozawa, K.; Pak, R.; Pantuev, V.; Papavassiliou, V.; Park, I. H.; Park, S.; Park, S. K.; Pate, S. F.; Patel, L.; Patel, M.; Peng, J. -C.; Perepelitsa, D. V.; Perera, G. D. N.; Peressounko, D. Yu.; Perry, J.; Petti, R.; Pinkenburg, C.; Pinson, R.; Pisani, R. P.; Purschke, M. L.; Qu, H.; Rak, J.; Ravinovich, I.; Read, K. F.; Reynolds, D.; Riabov, V.; Riabov, Y.; Richardson, E.; Riveli, N.; Roach, D.; Rolnick, S. D.; Rosati, M.; Rowan, Z.; Rubin, J. G.; Ryu, M. S.; Sahlmueller, B.; Saito, N.; Sakaguchi, T.; Sako, H.; Samsonov, V.; Sarsour, M.; Sato, S.; Sawada, S.; Schaefer, B.; Schmoll, B. K.; Sedgwick, K.; Seele, J.; Seidl, R.; Sekiguchi, Y.; Sen, A.; Seto, R.; Sett, P.; Sexton, A.; Sharma, D.; Shaver, A.; Shein, I.; Shibata, T. -A.; Shigaki, K.; Shimomura, M.; Shoji, K.; Shukla, P.; Sickles, A.; Silva, C. L.; Silvermyr, D.; Singh, B. K.; Singh, C. P.; Singh, V.; Skolnik, M.; Slune?ka, M.; Solano, S.; Soltz, R. A.; Sondheim, W. E.; Sorensen, S. P.; Soumya, M.; Sourikova, I. V.; Stankus, P. W.; Steinberg, P.; Stenlund, E.; Stepanov, M.; Ster, A.; Stoll, S. P.; Stone, M. R.; Sugitate, T.; Sukhanov, A.; Sumita, T.; Sun, J.; Sziklai, J.; Takahara, A.; Taketani, A.; Tanida, K.; Tannenbaum, M. J.; Tarafdar, S.; Taranenko, A.; Tennant, E.; Timilsina, A.; Todoroki, T.; Tomek, M.; Torii, H.; Towell, M.; Towell, R.; Towell, R. S.; Tserruya, I.; van Hecke, H. W.; Vargyas, M.; Vazquez-Zambrano, E.; Veicht, A.; Velkovska, J.; Vrtesi, R.; Virius, M.; Vrba, V.

    2014-12-18

    We report on J/? production from asymmetric Cu+Au heavy-ion collisions at \\(\\sqrt{s_{\\mathrm{NN}}} = 200\\) GeV at the Relativistic Heavy Ion Collider at both forward (Cu-going direction) and backward (Au-going direction) rapidities. The nuclear modification of J/? yields in Cu+Au collisions in the Au-going direction is found to be comparable to that in Au+Au collisions when plotted as a function of the number of participating nucleons. In the Cu-going direction, J/? production shows a stronger suppression. This difference is comparable in magnitude and has the same sign as the difference expected from shadowing effects due to stronger low-x gluon suppression in the larger Au nucleus. Thus, the relative suppression is opposite to that expected from hot nuclear matter dissociation, since a higher energy density is expected in the Au-going direction.

  18. Limitation of the Open-Circuit Voltage Due to Metastable Intrinsic Defects in Cu(In,Ga)Se2 and Strategies to Avoid These Defects: Preprint

    SciTech Connect (OSTI)

    Lany, S.; Zunger, A.

    2008-05-01

    This paper summarizes using first-principles defect theory to investigate the role of intrinsic point defects in the limitation of the open-circuit voltage (VOC) in Cu(In,Ga)Se2 solar cells.

  19. Nanoscale coherent intergrowths in a crystal of La?.?Ca?.?Cu?O??? made superconducting by high-pressure oxygen annealing

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Hu, Hefei; Zhu, Yimei; Shi, Xiaoya; Li, Qiang; Zhong, Ruidan; Schneeloch, John A.; Gu, Genda; Tranquada, John M.; Billinge, Simon J. L.

    2014-10-28

    Superconductivity with Tc = 53.5 K has been induced in a large La?.?Ca?.?Cu?O? (La-2126) single crystal by annealing in a high partial-pressure of oxygen at 1200C. Using transmission electron microscopy (TEM) techniques, we show that a secondary Ca-doped La?CuO? (La-214) phase, not present in the as-grown crystal, appears as a coherent intergrowth as a consequence of the annealing. A corresponding secondary superconducting transition near 13 K is evident in the magnetization measurement. Electron energy loss spectroscopy (EELS) reveals a pre-edge peak at the O K edge in the superconducting La-2126 phase, which is absent in the as-grown crystal, confirming themorehole-doping by interstitial oxygen.less

  20. A High-Yield Synthesis of Chalcopyrite CuInS2Nanoparticles with Exceptional Size Control

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Sun, Chivin; Gardner, Joseph S.; Shurdha, Endrit; Margulieux, Kelsey R.; Westover, Richard D.; Lau, Lisa; Long, Gary; Bajracharya, Cyril; Wang, Chongmin; Thurber, Aaron; et al

    2009-01-01

    We report high-yield and efficient size-controlled syntheses of Chalcopyrite CuInS2nanoparticles by decomposing molecular single source precursors (SSPs) via microwave irradiation in the presence of 1,2-ethanedithiol at reaction temperatures as low as 100C and times as short as 30?minutes. The nanoparticles sizes were 1.8?nm to 10.8?nm as reaction temperatures were varied from 100C to 200C with the bandgaps from 2.71?eV to 1.28?eV with good size control and high yields (64%95%). The resulting nanoparticles were analyzed by XRD, UV-Vis, ICP-OES, XPS, SEM, EDS, and HRTEM. Titration studies by1H NMR using SSP1with 1,2-ethanedithiol and benzyl mercaptan were conducted to elucidate the formation ofmoreChalcopyrite CuInS2nanoparticles.less

  1. Effect of Cu{sup 2+} and Ni{sup 2+} substitution at the Mn site in (La{sub

    Office of Scientific and Technical Information (OSTI)

    0.63}Ca{sub 0.37})MnO{sub 3}: A neutron powder diffraction investigation (Journal Article) | SciTech Connect Effect of Cu{sup 2+} and Ni{sup 2+} substitution at the Mn site in (La{sub 0.63}Ca{sub 0.37})MnO{sub 3}: A neutron powder diffraction investigation Citation Details In-Document Search Title: Effect of Cu{sup 2+} and Ni{sup 2+} substitution at the Mn site in (La{sub 0.63}Ca{sub 0.37})MnO{sub 3}: A neutron powder diffraction investigation The crystal and magnetic structures of the

  2. Temperature Dependence of the Kondo Resonance and Its Satellites in CeCu{sub 2}Si{sub 2}

    SciTech Connect (OSTI)

    Reinert, F.; Ehm, D.; Schmidt, S.; Nicolay, G.; Huefner, S.; Kroha, J.; Trovarelli, O.; Geibel, C.

    2001-09-03

    We present high-resolution photoemission spectroscopy studies on the Kondo resonance of the strongly correlated Ce system CeCu{sub 2}Si {sub 2} . By exploiting the thermal broadening of the Fermi edge we analyze position, spectral weight, and temperature dependence of the low-energy 4f spectral features, whose major weight lies above the Fermi level E{sub F} . We also present theoretical predictions based on the single-impurity Anderson model using an extended noncrossing approximation, including all spin-orbit and crystal field splittings of the 4f states. The excellent agreement between theory and experiment provides strong evidence that the spectral properties of CeCu{sub 2}Si {sub 2} can be described by single-impurity Kondo physics down to T{approx}5 K .

  3. Pd/Cu Site Interchange and Non-Fermi-Liquid Behavior in UCu{sub 4}Pd

    SciTech Connect (OSTI)

    Booth, C.H.; MacLaughlin, D.E.; Heffner, R.H.; Kwei, G.H. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)] [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); MacLaughlin, D.E. [Department of Physics, University of California, Riverside, California 92521 (United States)] [Department of Physics, University of California, Riverside, California 92521 (United States); Chau, R.; Maple, M.B. [Department of Physics, University of California, San Diego, California 92093 (United States)] [Department of Physics, University of California, San Diego, California 92093 (United States)

    1998-11-01

    X-ray-absorption fine-structure measurements of the local structure in UCu{sub 4}Pd are described which indicate a probable lattice-disorder origin for non-Fermi-liquid behavior in this material. Short Pd-Cu distances are observed, consistent with (24{plus_minus}3){percent} of the Pd atoms occupying nominally Cu sites. A {open_quotes}Kondo disorder{close_quotes} model, based on the effect on the local Kondo temperature T{sub K} of this interchange and some additional bond-length disorder, agrees quantitatively with previous experimental susceptibility data, and therefore also with specific heat and magnetic resonance experiments. {copyright} {ital 1998} {ital The American Physical Society }

  4. Antisite Defects in Layered Multiferroic CuCr0.9In0.1P2S6

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    He, Qian; Belianinov, Alex; Dziaugys, Andrius; Maksymovych, Petro; Vysochanskii, Yulian; Kalinin, Sergei V.; Borisevich, Albina Y.

    2015-10-06

    The CuCr1-xInxP2S6 system represents a large family of metal chalcogenophosphates that are unique and promising candidates for 2D materials with functionalities such as ferroelectricity. We carried out detailed microstructural and chemical characterization of these compounds using aberration-corrected STEM, in order to understand the origin of these different ordering phenomena. Quantitative STEM-HAADF imaging and analysis identified the stacking order of an 8-layer thin flake, which leads to the identification of anti-site In3+(Cu+) doping. We believe that these findings will pave the way towards understanding the ferroic coupling phenomena in van der Waals lamellar compounds, as well as the potential applications inmore » 2-D electronics.« less

  5. High-resolution neutron diffraction study of CuNCN: New evidence of structure anomalies at low temperature

    SciTech Connect (OSTI)

    Jacobs, Philipp; Houben, Andreas; Dronskowski, Richard; Tchougreff, Andrei L.; Lomonosov Moscow State University, Department of Chemistry and Poncelet Laboratory of Mathematics in Interaction with Physics and Informatics, Independent University of Moscow, Moscow Center for Continuous Mathematical Education, Bolshoi Vlasevsky Per. 11, 119002 Moscow

    2013-12-14

    Copper carbodiimide (CuNCN) is the nitrogen-containing analogue of cupric oxide. Based on high-resolution neutron-diffraction data, CuNCN's lattice parameters are derived as a function of the temperature. In accordance with a recent synchrotron study, a clear trend in the cell parameter a is observed accompanying the changing magnetic behavior. With decreasing temperature, a slowly decreases to a minimum at ?100 K after which it rises again. The same trendalbeit more pronouncedis observed for the c lattice parameter at ?35 K. The herein presented neutron powder-diffraction data also support the conjectured sequence of transitions from the high-temperature one-dimensional resonating valence-bond (RVB) state to a transient two-dimensional RVB state and eventually, at lowest temperatures, into another two-dimensional RVB state, presumably the ground state.

  6. Optical spectroscopic study of inverted cylindrical magnetron sputtering of YBa sub 2 Cu sub 3 O sub 7 minus x

    SciTech Connect (OSTI)

    Xi, X.X.; Wu, X.D.; Inam, A.; Li, Q.; Hemmick, D.; Findikoglu, A. ); Venkatesan, T.; Chang, C.C. ); Howard, R. )

    1990-07-02

    Optical spectroscopic studies of the plasma generated by inverted cylindrical magnetron sputtering of the high-temperature superconductor YBa{sub 2}Cu{sub 3}O{sub 7{minus}{ital x}} reveal strong ionic emissions from cation elements as well as from the sputter gases. The emissions of cationic ions are weakened drastically when O{sub 2} is added into the sputter gas indicating the dominating role of ions in the reaction with oxygen to form gas phase oxides. The formation of gas phase oxides is proposed to be an important precursor step for the {ital in} {ital situ} deposition of YBa{sub 2}Cu{sub 3}O{sub 7{minus}{ital x}} thin films.

  7. Methanol Synthesis over Cu/ZnO/Al2O3: The Active Site in Industrial Catalysis

    SciTech Connect (OSTI)

    Behrens, Malte

    2012-03-28

    Unlike homogeneous catalysts, heterogeneous catalysts that have been optimized through decades are typically so complex and hard to characterize that the nature of the catalytically active site is not known. This is one of the main stumbling blocks in developing rational catalyst design strategies in heterogeneous catalysis. We show here how to identify the crucial atomic structure motif for the industrial Cu/ZnO/Al{sub 2}O{sub 3} methanol synthesis catalyst. Using a combination of experimental evidence from bulk-, surface-sensitive and imaging methods collected on real high-performance catalytic systems in combination with DFT calculations. We show that the active site consists of Cu steps peppered with Zn atoms, all stabilized by a series of well defined bulk defects and surface species that need jointly to be present for the system to work.

  8. Structural and magnetic phase transitions in CeCu6-xTx (T = Ag,Pd)

    SciTech Connect (OSTI)

    Poudel, Lekhanath N.; De la cruz, Clarina; Payzant, E. Andrew; Koehler, Michael R.; May, Andrew F.; Garlea, Vasile O.; Taylor, Alice E.; Parker, David S.; Cao, Huibo B.; McGuire, Michael A.; Tian, Wei; Matsuda, Masaaki; Jeen, Hyoung Jeen; Lee, Ho Nyung; Hong, Tao; Calder, Stuart A.; Lumsden, Mark D.; Zhou, Haidong; Keppens, Veerle; Mandrus, D.; Christianson, Andrew D.

    2015-12-15

    The structural and the magnetic properties of CeCu6-xAgx (0 ≤ x ≤ 0.85) and CeCu6-xPdx (0 ≤ x ≤ 0.4) have been studied using neutron diffraction, resonant ultrasound spectroscopy (RUS), x-ray diffraction measurements, and first principles calculations. The structural and magnetic phase diagrams of CeCu6-xAgx and CeCu6-xPdx as a function of Ag/Pd composition are reported. The end member, CeCu6, undergoes a structural phase transition from an orthorhombic (Pnma) to a monoclinic (P21/c) phase at 240 K. In CeCu6-xAgx, the structural phase transition temperature (Ts) decreases linearly with Ag concentration and extrapolates to zero at xS ≈ 0.1. The structural transition in CeCu6-xPdx remains unperturbed with Pd substitution within the range of our study. The lattice constant b slightly decreases with Ag/Pd doping, whereas a and c increase with an overall increase in the unit cell volume. Both systems, CeCu6-xAgx and CeCu6-xPdx, exhibit a magnetic quantum critical point (QCP), at x ≈ 0.2 and x ≈ 0.05, respectively. Near the QCP, long range antiferromagnetic ordering takes place at an incommensurate wave vector (δ1 0 δ2), where δ1 ~ 0.62, δ2 ~ 0.25, x = 0.125 for CeCu6-xPdx and δ1 ~ 0.64, δ2 ~ 0.3, x = 0.3 for CeCu6-xAgx. As a result, the magnetic structure consists of an amplitude modulation of the Ce moments which are aligned along the c axis of the orthorhombic unit cell.

  9. Study of supported PtCu and PdAu bimetallic nanoparticles using in-situ x-ray tools.

    SciTech Connect (OSTI)

    Oxford, S. M.; Lee, P. L.; Chupas, P. J.; Chapman, K. W.; Kung, M. C.; Kung, H. H.; Northwestern Univ.

    2010-01-01

    A combination of two synchrotron X-ray techniques, X-ray absorption spectroscopy (XAS), and pair distribution function analysis (PDF) with complementary Fourier transform infrared (FTIR) spectroscopy measurement, was used to characterize the composition distributions of PdAu and PtCu bimetallic particles after treatment in H{sub 2} or CO and in the presence of these gases. This is the first reported application of PDF to the study of supported bimetallic nanoparticles. We found that XAS was informative in determining the component distribution of an initial sample, but PDF was better suited to following changes in the distribution upon changing the gas environment. Thus, the surface of a PtCu bimetallic particle of about 2.5 nm after treatment in H{sub 2} was found to be enriched in Cu, while the core was bimetallic. There was no evidence of a component-segregated core?shell structure. Treatment in CO caused enrichment of Pt to the surface layer, with a concomitant migration of Cu to the core. The average particle size remained the same. For the PdAu bimetallic particles, the surface and core compositions were similar after H{sub 2} treatment, and Pd was enriched in the surface after CO treatment. The X-ray results compared favorably to infrared spectroscopy results. The results demonstrated that the two X-ray techniques in combination can generate new information not available with either technique alone or other techniques, about the elemental distribution of bimetallic particles under conditions relevant to catalysis. They could provide new insight into structure-function relationships and time-on-stream behavior of bimetallic catalysts.

  10. Synthesis, transport properties, and electronic structure of Cu{sub 2}CdSnTe{sub 4}

    SciTech Connect (OSTI)

    Dong, Yongkwan; Khabibullin, Artem R.; Wei, Kaya; Ge, Zhen-Hua; Woods, Lilia M. Nolas, George S.; Martin, Joshua; Salvador, James R.

    2014-06-23

    A new stannite phase was synthesized and its temperature dependent transport properties were investigated. Cu{sub 2}CdSnTe{sub 4} possesses strong p-type conduction, while the temperature dependence of the thermal conductivity exhibits typical dielectric behavior. Electronic structure calculations allowed for a description of the transport characteristics in terms the energy band structure, density of states, and Fermi surface. The potential for thermoelectric applications is also discussed.

  11. Creep and oxidation behavior of modified CF8C-plus with W, Cu, Ni, and Cr

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Unocic, Kinga A.; Dryepondt, Sebastien N.; Yamamoto, Yukinori; Maziasz, Philip J.

    2016-02-01

    Here, the microstructures of modified CF8C-Plus (Fe-19Cr-12Ni-0.4W-3.8Mn-0.2Mo-0.6Nb-0.5Si-0.9C) with W and Cu (CF8CPWCu) and CF8CPWCu enhanced with 21Cr + 15Ni or 22Cr + 17.5Ni were characterized in the as-cast condition and after creep testing. When imaged at lower magnifications, the as-cast microstructure was similar among all three alloys as they all contained a Nb-rich interdendritic phase and Mn-based inclusions. Transmission electron microscopy (TEM) analysis showed the presence of nanoscale Cu-rich nanoprecipitates distributed uniformly throughout the matrix of CF8CPWCu, whereas in CF8CPWCu22/17, Cu precipitates were found primarily at the grain boundaries. The presence of these nanoscale Cu-rich particles, in addition to W-richmore » Cr23C6, nanoscale Nb carbides, and Z-phase (Nb2Cr2N2), improved the creep strength of the CF8CPWCu steel. Modification of CF8CPWCu with Cr and Ni contents slightly decreased the creep strength but significantly improved the oxidation behavior at 1073 K (800 °C). In particular, the addition of 22Cr and 17.5Ni strongly enhanced the oxidation resistance of the stainless steel resulting in a 100 degrees or greater temperature improvement, and this composition provided the best balance between improving both mechanical properties and oxidation resistance.« less

  12. Phase diagram and superconductive properties of splat-cooled Cu/sub x/La/sub 1-x/

    SciTech Connect (OSTI)

    Favaron, J.; de la Cruz, M.E.; Esquinazi, P.; de la Cruz, F.

    1980-04-01

    The phase diagram of nonequilibrium, splat-cooled Cu/sub x/La/sub 1-x/ is interpreted by means of superconductive-transition and x-ray measurements. At the eutectic composition the material is shown to be in a highly disordered state. Measurements of dc resistance and ac susceptibility show that there are two different critical fields at the disordered concentration although there is a unique critical temperature.

  13. Thermodynamic evidence for the Bose glass transition in twinnedYBa2Cu3O7-δcrystals

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Pérez-Morelo, D. J.; Osquiguil, E.; Kolton, A. B.; Nieva, G.; Jung, I. W.; López, D.; Pastoriza, H.

    2015-07-21

    We used a micromechanical torsional oscillator to measure the magnetic response of a twinned YBaBa2Cu3O7-δ single crystal disk near the Bose glass transition. We observe an anomaly in the temperature dependence of the magnetization consistent with the appearance of a magnetic shielding perpendicular to the correlated pinning of the twin boundaries. This effect is related to the thermodynamic transition from the vortex liquid phase to a Bose glass state.

  14. In-situ DRIFTS measurements for the mechanistic study of NO oxidation over a commercial Cu-CHA catalyst

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Ruggeri, Maria Pia; Nova, Isabella; Tronconi, Enrico; Pihl, Josh A.; Toops, Todd J.; Partridge, Jr., William P.

    2014-11-03

    We report a mechanistic DRIFTS in-situ study of NO2, NO + O2 and NO adsorption on a commercial Cu-CHA catalyst for NH3-SCR of NOx. Both pre-reduced and pre-oxidized catalyst samples were investigated with the aim of clarifying mechanistic aspects of the NO oxidation to NO2 as a preliminary step towards the study of the Standard SCR reaction mechanism at low temperatures. Nitrosonium cations (NO+, N formal oxidation state = +3) were identified as key surface intermediates in the process of NO (+2) oxidation to NO2 (+4) and nitrates (+5). While NO+ and nitrates were formed simultaneously upon catalyst exposure tomore » NO2, nitrates evolved consecutively to NO+ when the catalyst was exposed to NO + O2, suggesting that nitrite-like species, and not NO2, are formed as the primary products of the NO oxidative activation over Cu-CHA. Upon catalyst exposure to NO only, i.e. in the absence of gaseous O2, NO+ and then nitrates were formed on a pre-oxidized sample but not on a pre-reduced one, which demonstrates the red-ox nature of the NO oxidation mechanism. The negative effect of H2O on NO+ and nitrates formation was also clearly established. Assuming Cu dimers as the active sites for NO oxidation to NO2, we propose a mechanism which reconciles all the experimental observations. Specifically, we show that such a mechanism also explains the observed kinetic effects of H2O, O2 and NO2 on the NO oxidation activity of the investigated Cu zeolite catalyst.« less

  15. Direct imaging of enhanced current collection on grain boundaries of Cu(In,Ga)Se{sub 2} solar cells

    SciTech Connect (OSTI)

    Kim, JunHo; Kim, SeongYeon; Jiang, Chun-Sheng; Ramanathan, Kannan; Al-Jassim, Mowafak M.

    2014-02-10

    We report on direct imaging of current collection by performing conductive atomic force microscopy (C-AFM) measurement on a complete Cu(In,Ga)Se{sub 2} solar cell. The localized current was imaged by milling away the top conductive layer of the device by repeated C-AFM scans. The result exhibits enhanced photocurrent collection on grain boundaries (GBs) of CIGS films, consistent with the argument for electric-field-assisted carrier collection on the GBs.

  16. Influence of leaching on surface composition, microstructure, and valence band of single grain icosahedral Al-Cu-Fe quasicrystal

    SciTech Connect (OSTI)

    Lowe, M.; McGrath, R.; Sharma, H. R.; Yadav, T. P.; Fourne, V.; Ledieu, J.

    2015-03-07

    The use of quasicrystals as precursors to catalysts for the steam reforming of methanol is potentially one of the most important applications of these new materials. To develop application as a technology requires a detailed understanding of the microscopic behavior of the catalyst. Here, we report the effect of leaching treatments on the surface microstructure, chemical composition, and valence band of the icosahedral (i-) Al-Cu-Fe quasicrystal in an attempt to prepare a model catalyst. The high symmetry fivefold surface of a single grain i-Al-Cu-Fe quasicrystal was leached with NaOH solution for varying times, and the resulting surface was characterized by x-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS), scanning electron microscopy (SEM), and atomic force microscopy (AFM). The leaching treatments preferentially remove Al producing a capping layer consisting of Fe and Cu oxides. The subsurface layer contains elemental Fe and Cu in addition to the oxides. The quasicrystalline bulk structure beneath remains unchanged. The subsurface gradually becomes Fe{sub 3}O{sub 4} rich with increasing leaching time. The surface after leaching exhibits micron sized dodecahedral cavities due to preferential leaching along the fivefold axis. Nanoparticles of the transition metals and their oxides are precipitated on the surface after leaching. The size of the nanoparticles is estimated by high resolution transmission microscopy to be 5-20 nm, which is in agreement with the AFM results. Selected area electron diffraction (SAED) confirms the crystalline nature of the nanoparticles. SAED further reveals the formation of an interface between the high atomic density lattice planes of nanoparticles and the quasicrystal. These results provide an important insight into the preparation of model catalysts of nanoparticles for steam reforming of methanol.

  17. Intermixing of InGaAs/GaAs Quantum Well Using Multiple Cycles Annealing Cu-doped SiO2

    SciTech Connect (OSTI)

    Hongpinyo, V; Ding, Y H; Dimas, C E; Wang, Y; Ooi, B S; Qiu, W; Goddard, L L; Behymer, E M; Cole, G D; Bond, T C

    2008-06-11

    The authors investigate the effect of intermixing in InGaAs/GaAs quantum well structure using Cu-doped SiO{sub 2}. The incorporation of Cu into the silica film yields larger bandgap shift than typical impurity-free vacancy diffusion (IFVD) method at a lower activation temperature. We also observe enhancement of the photoluminescence (PL) signal from the intermixed InGaAs/GaAs quantum well structure after being cycle-annealed at 850 C.

  18. Dispersion of the linear and nonlinear optical susceptibilities of the CuAl(S{sub 1x}Se{sub x})? mixed chaclcopyrite compounds

    SciTech Connect (OSTI)

    Reshak, A. H.; Brik, M. G.; Auluck, S.

    2014-09-14

    Based on the electronic band structure, we have calculated the dispersion of the linear and nonlinear optical susceptibilities for the mixed CuAl(S{sub 1x}Se{sub x})? chaclcopyrite compounds with x=0.0, 0.25, 0.5, 0.75, and 1.0. Calculations are performed within the Perdew-Becke-Ernzerhof general gradient approximation. The investigated compounds possess a direct band gap of about 2.2 eV (CuAlS?), 1.9 eV (CuAl(S?.??Se?.??)?), 1.7 eV (CuAl(S?.?Se?.?)?), 1.5 eV (CuAl(S?.??Se?.??)?), and 1.4 eV (CuAlSe?) which tuned to make them optically active for the optoelectronics and photovoltaic applications. These results confirm that substituting S by Se causes significant band gaps' reduction. The optical function's dispersion ??{sup xx}(?) and ??{sup zz}(?)/??{sup xx}(?), ??{sup yy}(?), and ??{sup zz}(?) was calculated and discussed in detail. To demonstrate the effect of substituting S by Se on the complex second-order nonlinear optical susceptibility tensors, we performed detailed calculations for the complex second-order nonlinear optical susceptibility tensors, which show that the neat parents compounds CuAlS? and CuAlSe? exhibit | ????}(-2?;?;?) | as the dominant component, while the mixed alloys exhibit | ????(-2?;?;?) | as the dominant component. The features of | ????}(-2?;?;?) | and | ?{sub 111}}(-2?;?;?) | spectra were analyzed on the basis of the absorptive part of the corresponding dielectric function ??(?) as a function of both ?/2 and ?.

  19. Synthesis and characterization of g-C{sub 3}N{sub 4}/Cu{sub 2}O composite catalyst with enhanced photocatalytic activity under visible light irradiation

    SciTech Connect (OSTI)

    Peng, Biyu; Zhang, Shengsen; Yang, Siyuan; Wang, Hongjuan; Yu, Hao; Zhang, Shanqing; Peng, Feng

    2014-08-15

    The prepared g-C{sub 3}N{sub 4}/Cu{sub 2}O composite exhibited the enhanced photocatalytic activity under visible-light irradiation due to the stronger ability in separation of electronhole pairs, which was proven by the transient photocurrent measurement. - Highlights: The coupled Cu{sub 2}O with g-C{sub 3}N{sub 4} of narrow-band-gap semiconductor has been designed. g-C{sub 3}N{sub 4}/Cu{sub 2}O is prepared via an alcohol-aqueous based on chemical precipitation method. g-C{sub 3}N{sub 4}/Cu{sub 2}O exhibits the enhanced photocatalytic activity under visible-light. The enhanced photocatalytic activity is proven by the transient photocurrent test. A mechanism for the visible-light-driven photocatalysis of g-C{sub 3}N{sub 4}/Cu{sub 2}O is revealed. - Abstract: To overcome the drawback of low photocatalytic efficiency brought by electronhole pairs recombination and narrow photo-response range, a novel g-C{sub 3}N{sub 4}/Cu{sub 2}O composite photocatalyst was designed and prepared successfully. Compared with bare Cu{sub 2}O and g-C{sub 3}N{sub 4}, the g-C{sub 3}N{sub 4}/Cu{sub 2}O composite exhibited significantly enhanced photocatalytic activity for acid orange-II (AO-II) degradation under visible light irradiation. Based on energy band positions, the mechanism of enhanced visible-light photocatalytic activity was proposed.

  20. Structural and optical properties of (Ag,Cu)(In,Ga)Se{sub 2} polycrystalline thin film alloys

    SciTech Connect (OSTI)

    Boyle, J. H.; Shafarman, W. N.; Birkmire, R. W.; McCandless, B. E.

    2014-06-14

    The structural and optical properties of pentenary alloy (Ag,Cu)(In,Ga)Se{sub 2} polycrystalline thin films were characterized over the entire compositional range at a fixed (Cu + Ag)/(In + Ga) ratio. Films deposited at 550 °C on bare and molybdenum coated soda-lime glass by elemental co-evaporation in a single-stage process with constant incident fluxes exhibit single phase chalcopyrite structure, corresponding to 122 spacegroup (I-42d) over the entire compositional space. Unit cell refinement of the diffraction patterns show that increasing Ag substitution for Cu, the refined a{sub o} lattice constant, (Ag,Cu)-Se bond length, and anion displacement increase in accordance with the theoretical model proposed by Jaffe, Wei, and Zunger. However, the refined c{sub o} lattice constant and (In,Ga)-Se bond length deviated from theoretical expectations for films with mid-range Ag and Ga compositions and are attributed to influences from crystallographic bond chain ordering or cation electronegativity. The optical band gap, derived from transmission and reflection measurements, widened with increasing Ag and Ga content, due to influences from anion displacement and cation electronegativity, as expected from theoretical considerations for pseudo-binary chalcopyrite compounds.

  1. Wide band gap p-type nanocrystalline CuBO{sub 2} as a novel UV photocatalyst

    SciTech Connect (OSTI)

    Santra, S.; Das, N.S.; Chattopadhyay, K.K.

    2013-07-15

    Graphical abstract: - Highlights: CuBO{sub 2} nanocrystals were synthesized by solgel route. The products have been characterized to confirm the formation of CuBO{sub 2}. Photocatalytic activity of this material is reported for the first time. - Abstract: Wide band gap copper based delafossite CuBO{sub 2} nanocrystalline powders of different particle sizes were synthesized via solgel route. Structural characterization was performed using X-ray diffraction (XRD) and transmission electron microscopy (TEM) which confirmed good crystallinity and proper phase formation of the samples. Compositional analysis was carried out by energy dispersive X-ray studies (EDX), whereas field emission scanning electron microscopy revealed morphological information of the samples. The photocatalytic performance of this delafossite material was studied for the first time with a standard photocatalytic set-up and the photocatalytic efficiency was found to increase with decreasing particle size. The LangmuirHinshelwood photocatalytic rate constants increased considerably for the samples synthesized at different pH from 2.75 to 0.5; which eventually varied particle size. The efficient photocatalytic performance, found for the first time here, will make this novel p-type wide band gap semiconductor a truly multifunctional material.

  2. Elucidating the sole contribution from electromagnetic near-fields in plasmon-enhanced Cu2O photocathodes

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    DuChene, Joseph S.; Williams, Benjamin P.; Johnston-Peck, Aaron C.; Qiu, Jingjing; Gomes, Mathieu; Amilhau, Maxime; Bejleri, Donald; Weng, Jiena; Su, Dong; Huo, Fengwei; et al

    2015-11-05

    Despite many promising reports of plasmon-enhanced photocatalysis, the inability to identify the individual contributions from multiple enhancement mechanisms has delayed the development of general design rules for engineering efficient plasmonic photocatalysts. Herein, we construct a plasmonic photocathode comprised of Au@SiO2 (core@shell) nanoparticles embedded within a Cu2O nanowire network to exclusively examine the contribution from one such mechanism: electromagnetic near-field enhancement. The influence of the local electromagnetic field intensity is correlated with the overall light-harvesting efficiency of the device through variation of the SiO2 shell thickness (5—22 nm) to systematically tailor the distance between the plasmonic Au nanoparticles and the Cu2Omore » nanowires. A three-fold increase in device photocurrent is achieved upon integrating the Au@SiO2 nanoparticles into the Cu2O nanowire network, further enabling a ~40% reduction in semiconductor film thickness while maintaining photocathode performance. Photoelectrochemical results are further correlated with photoluminescence studies and optical simulations to confirm that the near-field enhancement is the sole mechanism responsible for increased light absorption in the plasmonic photocathode.« less

  3. Impact of deformation on the atomic structures and dynamics of a Cu-Zr metallic glass: A molecular dynamics study

    SciTech Connect (OSTI)

    Zhang, Y.; Mendelev, M. I.; Wang, C. Z.; Ott, R.; Zhang, F.; Besser, M. F.; Ho, K. M.; Kramer, M. J.

    2014-11-03

    Despite numerous studies on the atomic structures of Cu-Zr metallic glasses (MGs), their inherent structural ordering, e.g., medium-range order (MRO), remains difficult to describe. Specifically lacking is an understanding of how the MRO responds to deformation and the associated changes in atomic mobility. In this paper, we focus on the impact of deformation on MRO and associated effect on diffusion in a well-relaxed Cu64.5Zr35.5 MG by molecular dynamics simulations. The Cu-Zr MG exhibits a larger elastic limit of 0.035 and a yield stress of 3.5 GPa. The cluster alignment method was employed to characterize the icosahedral short-range order (ISRO) and Bergman-type medium-range order (BMRO) in the models upon loading and unloading. From this analysis, we find the disruption of both ISRO and BMRO occurs as the strain reaches about 0.02, well below the elastic limit. Within the elastic limit, the total fractions of ISRO or BMRO can be fully recovered upon unloading. The diffusivity increases six to eight times in regions undergoing plastic deformation, which is due to the dramatic disruption of the ISRO and BMRO. As a result, by mapping the spatial distributions of the mobile atoms, we demonstrate the increase in atomic mobility is due to the extended regions of disrupted ISRO and more importantly BMRO.

  4. Optical and electronic properties of delafossite CuBO{sub 2}p-type transparent conducting oxide

    SciTech Connect (OSTI)

    Ruttanapun, Chesta E-mail: krchesta@kmitl.ac.th

    2013-09-21

    CuBO{sub 2} delafossite was prepared by solid state reaction and calcined/sintered at 1005?C. The optical properties of this p-type transparent conducting oxide were investigated. Its crystal structure, morphology, composition, oxygen decomposition, and optical and electronic properties were characterized by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, thermal gravimetric analysis (TGA), ultraviolet-visible-near-infrared (UV-VIS-NIR) and fluorescence spectroscopies, Seebeck coefficient, and electrical conductivity measurements. CuBO{sub 2} delafossite possesses a hexagonal space group R3{sup }m. TGA indicated a weight loss of 10%, which was attributed to excess oxygen. The positive Seebeck coefficient confirmed p-type behavior. Emission at 355?nm indicated a direct band type transition, and the UV-VIS-NIR spectrum indicated an optical direct gap of 3.6?eV. Activation energies for carrier production and electrical conduction were 0.147 and 0.58?eV, respectively, indicating the thermal activation of carriers. CuBO{sub 2} delafossite is a p-type transparent conducting oxide with a wide band gap and may have potential in industrial p-type electrodes.

  5. Impact of deformation on the atomic structures and dynamics of a Cu-Zr metallic glass: A molecular dynamics study

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Zhang, Y.; Mendelev, M. I.; Wang, C. Z.; Ott, R.; Zhang, F.; Besser, M. F.; Ho, K. M.; Kramer, M. J.

    2014-11-03

    Despite numerous studies on the atomic structures of Cu-Zr metallic glasses (MGs), their inherent structural ordering, e.g., medium-range order (MRO), remains difficult to describe. Specifically lacking is an understanding of how the MRO responds to deformation and the associated changes in atomic mobility. In this paper, we focus on the impact of deformation on MRO and associated effect on diffusion in a well-relaxed Cu64.5Zr35.5 MG by molecular dynamics simulations. The Cu-Zr MG exhibits a larger elastic limit of 0.035 and a yield stress of 3.5 GPa. The cluster alignment method was employed to characterize the icosahedral short-range order (ISRO) andmore » Bergman-type medium-range order (BMRO) in the models upon loading and unloading. From this analysis, we find the disruption of both ISRO and BMRO occurs as the strain reaches about 0.02, well below the elastic limit. Within the elastic limit, the total fractions of ISRO or BMRO can be fully recovered upon unloading. The diffusivity increases six to eight times in regions undergoing plastic deformation, which is due to the dramatic disruption of the ISRO and BMRO. As a result, by mapping the spatial distributions of the mobile atoms, we demonstrate the increase in atomic mobility is due to the extended regions of disrupted ISRO and more importantly BMRO.« less

  6. Magnetic excitations in the spin-1/2 triangular-lattice antiferromagnet Cs2CuBr4

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Zvyagin, S. A.; Ozerov, M.; Kamenskyi, D.; Wosnitza, J.; Krzystek, J.; Yoshizawa, D.; Hagiwara, M.; Hu, Rongwei; Ryu, Hyejin; Petrovic, C.; et al

    2015-11-27

    We present on high- field electron spin resonance (ESR) studies of magnetic excitations in the spin- 1/2 triangular-lattice antiferromagnet Cs2CuBr4. Frequency- field diagrams of ESR excitations are measured for different orientations of magnetic fields up to 25 T. We show that the substantial zero- field energy gap, Δ ≈ 9.5 K, observed in the low-temperature excitation spectrum of Cs2CuBr4 [Zvyagin et al:, Phys. Rev. Lett. 112, 077206 (2014)], is present well above TN. Noticeably, the transition into the long-range magnetically ordered phase does not significantly affect the size of the gap, suggesting that even below TN the high-energy spin dynamicsmore » in Cs2CuBr4 is determined by short-range-order spin correlations. The experimental data are compared with results of model spin-wave-theory calculations for spin-1/2 triangle-lattice antiferromagnet.« less

  7. Calculation of combined diffusion coefficients in SF{sub 6}-Cu mixtures

    SciTech Connect (OSTI)

    Zhong, Linlin; Wang, Xiaohua Rong, Mingzhe Wu, Yi; Murphy, Anthony B.

    2014-10-15

    Diffusion coefficients play an important role in the description of the transport of metal vapours in gas mixtures. This paper is devoted to the calculation of four combined diffusion coefficients, namely, the combined ordinary diffusion coefficient, combined electric field diffusion coefficient, combined temperature diffusion coefficient, and combined pressure diffusion coefficient in SF{sub 6}-Cu mixtures at temperatures up to 30?000?K. These four coefficients describe diffusion due to composition gradients, applied electric fields, temperature gradients, and pressure gradients, respectively. The influence of copper fluoride and sulfide species on the diffusion coefficients is shown to be negligible. The effect of copper proportion and gas pressures on these diffusion coefficients is investigated. It is shown that increasing the proportion of copper generally increases the magnitude of the four diffusion coefficients, except for copper mole fractions of 90% or more. It is further found that increasing the pressure reduces the magnitude of the coefficients, except for the combined temperature diffusion coefficient, and shifts the maximum of all four coefficients towards higher temperatures. The results presented in this paper can be applied to the simulation of high-voltage circuit breaker arcs.

  8. Processing approach towards the formation of thin-film Cu(In,Ga)Se2

    DOE Patents [OSTI]

    Beck, Markus E.; Noufi, Rommel

    2003-01-01

    A two-stage method of producing thin-films of group IB-IIIA-VIA on a substrate for semiconductor device applications includes a first stage of depositing an amorphous group IB-IIIA-VIA precursor onto an unheated substrate, wherein the precursor contains all of the group IB and group IIIA constituents of the semiconductor thin-film to be produced in the stoichiometric amounts desired for the final product, and a second stage which involves subjecting the precursor to a short thermal treatment at 420.degree. C.-550.degree. C. in a vacuum or under an inert atmosphere to produce a single-phase, group IB-III-VIA film. Preferably the precursor also comprises the group VIA element in the stoichiometric amount desired for the final semiconductor thin-film. The group IB-IIIA-VIA semiconductor films may be, for example, Cu(In,Ga)(Se,S).sub.2 mixed-metal chalcogenides. The resultant supported group IB-IIIA-VIA semiconductor film is suitable for use in photovoltaic applications.

  9. In situ measurement of CuPt alloy ordering using strain anisotropy

    SciTech Connect (OSTI)

    France, Ryan M.; McMahon, William E.; Kang, Joongoo; Steiner, Myles A.; Geisz, John F.

    2014-02-07

    The optical and electrical properties of many III-V alloys change with the degree of CuPt atomic ordering, which is very sensitive to growth conditions. The bulk ordered alloy is elongated along the normal to the ordered planes, and is asymmetrically strained when coherent to a cubic substrate. Here, we demonstrate in situ measurement of the anisotropic strain due to ordering using two-dimensional wafer curvature. The measurement is sensitive to bulk anisotropies, and so is complementary to other in situ measurements that are sensitive to surface anisotropies. Using ab initio calculations, we determine a maximum strain anisotropy of 0.27% between [110] and [1{sup ¯}10] when perfectly ordered single-variant GaInP{sub 2} is coherent to a (001) cubic substrate. We relate the in situ measurement of strain anisotropy on various GaInP{sub 2} samples to ex situ measurements of the order parameter to validate the measurement and confirm the capability to predict material properties. The measurement monitors change in ordering during growth, useful for quickly determining the growth condition dependence of ordering or monitoring order-disorder transitions. More generally, this measurement technique could, in principle, be used to monitor phase changes in any epitaxial system for which the strain anisotropy of the two phases differs.

  10. Preparation of Cu and Fly Ash Composite by Powder Metallurgy Technique

    SciTech Connect (OSTI)

    Chew, P. Y.; Lim, P. S.; Ng, M. C.; Zahi, S.; You, A. H.

    2011-03-30

    Cu and Fly Ash (FA) mixtures with different weight percentages were prepared. Pellets of the mixture powder were produced with the dimension of 17.7 mm in diameter and 10-15 mm in height. These different composites were compacted at a constant pressure of 280 MPa. One of the selected weight percentages was then compacted to form into pellet and sintered at different temperatures which were at 900, 950 and 1000 deg. C respectively for 2 hours. Density of green pellet was measured before sintered in furnace. After sintering, all the pellets with different temperatures were re-weighed and sintered density were calculated. The densification of the green and sintered pellets was required to be measured as one of the parameter in selection of the best material properties. Porosity of the pellet shall not be ignored in order to analyze the close-packed particles stacking in the pellet. SEM micrograph had been captured to observe the presence of pores and agglomeration of particles in the sample produced.

  11. Performance Characterization and Remedy of Experimental CuInGaSe2 Mini-Modules: Preprint

    SciTech Connect (OSTI)

    Pern, F. J.; Yan, F.; Mansfield, L.; Glynn, S.; Rekow, M.; Murion, R.

    2011-07-01

    We employed current-voltage (I-V), quantum efficiency (QE), photoluminescence (PL), electroluminescence (EL), lock-in thermography (LIT), and (electrochemical) impedance spectroscopy (ECIS) to complementarily characterize the performance and remedy for two pairs of experimental CuInGaSe2 (CIGS) mini-modules. One pair had the three scribe-lines (P1/P2/P3) done by a single pulse-programmable laser, and the other had the P2/P3 lines by mechanical scribe. Localized QE measurements for each cell strip on all four mini-modules showed non-uniform distributions that correlated well with the presence of performance-degrading strips or spots revealed by PL, EL, and LIT imaging. Performance of the all-laser-scribed mini-modules improved significantly by adding a thicker Al-doped ZnO layer and reworking the P3 line. The efficiency on one of the all-laser-scribed mini-modules increased notably from 7.80% to 8.56% after the performance-degrading spots on the side regions along the cell array were isolated by manual scribes.

  12. Electrochemical synthesis of Nb3Sn coatings on Cu substrates

    SciTech Connect (OSTI)

    Franz, S.; Barzi, E.; Turrioni, D.; Glionna, L.; Bestetti, M.

    2015-09-11

    This study aims at contributing to the development of superconducting Nb3Sn thin films for possible applications, as for instance in superconducting radio frequency (SRF) cavities. The synthesis of Nb-Sn coatings was carried out on copper substrates by electrodeposition from 1-Butyl-3-methylimidazolium chloride (BMIC) ionic liquids containing SnCl2 and NbCl5. Cyclic voltammetric curves were recorded to identify the reduction potentials of Nb and Sn ionic species. Electrodeposition was performed at 40 and 400 mA/cm2 and 130°C. The CV demonstrated that BMIC has a suitable potential window for co-deposition of Nb and Sn. The electrodeposited coatings showed a cubic Nb3Sn phase with (211) preferred orientation, a disordered orthorhombic NbSn2 phase and Sn-Cu phases. Film thickness was from 200 to 750 nm. These results suggest that electrodeposition of Nb-Sn coatings on copper substrates could be a suitable route to one day replace the current expensive Nb SRF cavities.

  13. Semiclassical multi-phonon theory for atom-surface scattering: Application to the Cu(111) system

    SciTech Connect (OSTI)

    Daon, Shauli; Pollak, Eli

    2015-05-07

    The semiclassical perturbation theory of Hubbard and Miller [J. Chem. Phys. 80, 5827 (1984)] is further developed to include the full multi-phonon transitions in atom-surface scattering. A practically applicable expression is developed for the angular scattering distribution by utilising a discretized bath of oscillators, instead of the continuum limit. At sufficiently low surface temperature good agreement is found between the present multi-phonon theory and the previous one-, and two-phonon theory derived in the continuum limit in our previous study [Daon, Pollak, and Miret-Arts, J. Chem. Phys. 137, 201103 (2012)]. The theory is applied to the measured angular distributions of Ne, Ar, and Kr scattered from a Cu(111) surface. We find that the present multi-phonon theory substantially improves the agreement between experiment and theory, especially at the higher surface temperatures. This provides evidence for the importance of multi-phonon transitions in determining the angular distribution as the surface temperature is increased.

  14. The magnetic structure of EuCu2Sb2

    SciTech Connect (OSTI)

    Ryan, D. H.; Cadogan, J. M.; Anand, V. K.; Johnston, D. C.; Flacau, R.

    2015-05-06

    Antiferromagnetic ordering of EuCu2Sb2 which forms in the tetragonal CaBe2Ge2-type structure (space group P4/nmm #129) has been studied using neutron powder diffraction and 151Eu Mössbauer spectroscopy. The room temperature 151Eu isomer shift of –12.8(1) mm/s shows the Eu to be divalent, while the 151Eu hyperfine magnetic field (Bhf) reaches 28.7(2) T at 2.1 K, indicating a full Eu2+ magnetic moment. Bhf(T) follows a smooth $S=\\frac{7}{2}$ Brillouin function and yields an ordering temperature of 5.1(1) K. Refinement of the neutron diffraction data reveals a collinear A-type antiferromagnetic arrangement with the Eu moments perpendicular to the tetragonal c-axis. As a result, the refined Eu magnetic moment at 0.4 K is 7.08(15) μB which is the full free-ion moment expected for the Eu2+ ion with $S=\\frac{7}{2}$ and a spectroscopic splitting factor of g = 2.

  15. The magnetic structure of EuCu2Sb2

    SciTech Connect (OSTI)

    Ryan, D. H.; Cadogan, J. M.; Anand, V. K.; Johnston, D. C.; Flacau, R.

    2015-05-06

    Antiferromagnetic ordering of EuCu2Sb2 which forms in the tetragonal CaBe2Ge2-type structure (space group P4/nmm #129) has been studied using neutron powder diffraction and 151Eu Mssbauer spectroscopy. The room temperature 151Eu isomer shift of 12.8(1) mm/s shows the Eu to be divalent, while the 151Eu hyperfine magnetic field (Bhf) reaches 28.7(2) T at 2.1 K, indicating a full Eu2+ magnetic moment. Bhf(T) follows a smooth $S=\\frac{7}{2}$ Brillouin function and yields an ordering temperature of 5.1(1) K. Refinement of the neutron diffraction data reveals a collinear A-type antiferromagnetic arrangement with the Eu moments perpendicular to the tetragonal c-axis. As a result, the refined Eu magnetic moment at 0.4 K is 7.08(15) ?B which is the full free-ion moment expected for the Eu2+ ion with $S=\\frac{7}{2}$ and a spectroscopic splitting factor of g = 2.

  16. High temperature superconductor step-edge Josephson junctions using Ti-Ca-Ba-Cu-O

    DOE Patents [OSTI]

    Ginley, D.S.; Hietala, V.M.; Hohenwarter, G.K.G.; Martens, J.S.; Plut, T.A.; Tigges, C.P.; Vawter, G.A.; Zipperian, T.E.

    1994-10-25

    A process is disclosed for formulating non-hysteretic and hysteretic Josephson junctions using HTS materials which results in junctions having the ability to operate at high temperatures while maintaining high uniformity and quality. The non-hysteretic Josephson junction is formed by step-etching a LaAlO[sub 3] crystal substrate and then depositing a thin film of TlCaBaCuO on the substrate, covering the step, and forming a grain boundary at the step and a subsequent Josephson junction. Once the non-hysteretic junction is formed the next step to form the hysteretic Josephson junction is to add capacitance to the system. In the current embodiment, this is accomplished by adding a thin dielectric layer, LaA1O[sub 3], followed by a cap layer of a normal metal where the cap layer is formed by first depositing a thin layer of titanium (Ti) followed by a layer of gold (Au). The dielectric layer and the normal metal cap are patterned to the desired geometry. 8 figs.

  17. Electronic structure and conductivity of nanocomposite metal (Au,Ag,Cu,Mo)-containing amorphous carbon films

    SciTech Connect (OSTI)

    Endrino, Jose L.; Horwat, David; Gago, Raul; Andersson, Joakim; Liu, Y.S.; Guo, Jinghua; Anders, Andre

    2008-05-14

    In this work, we study the influence of the incorporation of different metals (Me = Au, Ag, Cu, Mo) on the electronic structure of amorphous carbon (a-C:Me) films. The films were produced at room temperature using a novel pulsed dual-cathode arc deposition technique. Compositional analysis was performed with secondary neutral mass spectroscopy whereas X-ray diffraction was used to identify the formation of metal nanoclusters in the carbon matrix. The metal content incorporated in the nanocomposite films induces a drastic increase in the conductivity, in parallel with a decrease in the band gap corrected from Urbach energy. The electronic structure as a function of the Me content has been monitored by x-ray absorption near edge structure (XANES) at the C K-edge. XANES showed that the C host matrix has a dominant graphitic character and that it is not affected significantly by the incorporation of metal impurities, except for the case of Mo, where the modifications in the lineshape spectra indicated the formation of a carbide phase. Subtle modifications of the spectral lineshape are discussed in terms of nanocomposite formation.

  18. Atomic structure of Cu-10. 9 at % Be alloys in the early stages of aging

    SciTech Connect (OSTI)

    Koo, Y.M.

    1987-01-01

    Diffuse x-ray scattering was employed to investigate the local atomic structure and static strains in a single crystal of a Cu-10.9 at. % Be alloy in the early stages of aging. In addition to these experiments, neutron elastic and inelastic scattering were obtained to investigate the phonon properties in the as-quenched state of this alloy. In the as-quenched state, there is a nearly regular array of small ellipsoidal Be clusters aligned along <100> directions (This produces the tweed contrast seen in TEM). The density of these clusters is 7.5 x 10/sup 26//m/sup 3/. The diffuse streaks seen in electron diffraction patterns are due largely to thermal diffuse scattering. Phonon-dispersion curves show no large differences from those of pure copper, except at (xi xi xi)/sub T/ zone boundary, where there is softening. This difference may be due to a Kohn anomaly. The elastic anisotropy of this alloy increases considerably with alloying, which probably leads to the plate-like GP zone morphology in subsequent aging treatments. The structure of the GP zones is a mixture of Be-rich single- and multi-layered zones. As aging proceeds, the zones grow in thickness.

  19. High temperature superconductor step-edge Josephson junctions using Ti-Ca-Ba-Cu-O

    DOE Patents [OSTI]

    Ginley, David S. (Evergreen, CO); Hietala, Vincent M. (Placitas, NM); Hohenwarter, Gert K. G. (Madison, WI); Martens, Jon S. (Sunnyvale, CA); Plut, Thomas A. (Albuquerque, NM); Tigges, Chris P. (Albuquerque, NM); Vawter, Gregory A. (Albuquerque, NM); Zipperian, Thomas E. (Albuquerque, NM)

    1994-10-25

    A process for formulating non-hysteretic and hysteretic Josephson junctions using HTS materials which results in junctions having the ability to operate at high temperatures while maintaining high uniformity and quality. The non-hysteretic Josephson junction is formed by step-etching a LaAlO.sub.3 crystal substrate and then depositing a thin film of TlCaBaCuO on the substrate, covering the step, and forming a grain boundary at the step and a subsequent Josephson junction. Once the non-hysteretic junction is formed the next step to form the hysteretic Josephson junction is to add capacitance to the system. In the current embodiment, this is accomplished by adding a thin dielectric layer, LaA1O.sub.3, followed by a cap layer of a normal metal where the cap layer is formed by first depositing a thin layer of titanium (Ti) followed by a layer of gold (Au). The dielectric layer and the normal metal cap are patterned to the desired geometry.

  20. Characterization of Cu(In,Ga)Se2 (CIGS) films with varying gallium ratios

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Claypoole, Jesse; Peace, Bernadette; Sun, Neville; Dwyer, Dan; Eisaman, Matthew D.; Haldar, Pradeep; Efstathiadis, Harry

    2015-09-05

    Cu(In1-x,Gax)Se2 (CIGS) absorber layers were deposited on molybdenum (Mo) coated soda-lime glass substrates with varying Ga content (described as Ga/(In+Ga) ratios) with respect to depth. As the responsible mechanisms for the limitation of the performance of the CIGS solar cells with high Ga contents are not well understood, the goal of this work was to investigate different properties of CIGS absorber films with Ga/(In+Ga) ratios varied between 0.29 and 0.41 (as determined by X-ray florescence spectroscopy (XRF)) in order to better understand the role that the Ga content has on film quality. The Ga grading in the CIGS layer hasmore » the effect causing a higher bandgap toward the surface and Mo contact while the band gap in the middle of the CIGS layer is lower. Also, a wider and larger Ga/(In+Ga) grading dip located deeper in the CIGS absorber layers tend to produce larger grains in the regions of the films that have lower Ga/(In+Ga) ratios. It was found that surface roughness decreases from 51.2 nm to 41.0 nm with increasing Ga/(In+Ga) ratios. However, the surface roughness generally decreases if the Ga grading occurs deeper in the absorber layer.« less