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Sample records for ia il mn

  1. IL

    Office of Legacy Management (LM)

    :; / 2. ' b-:-"y .",...4 * .-.a 2 IL !< :. 34 --' -, ' ' < I ,-. g Tvo"l r . . .-i- :- " .1-. . . . . NC0 /L ' J,, ' ;.' , -_I( + ? CENTRAL FILES c -&' { ' c;$y ;;j*' E ,J): ' i' Z, 1; p -^ r-raL-r.nuzT".Fn., , ,..-y - -' -ie .". iJ.&:~e!ct.;;' sf ' ;;i_is ,trip ' JG,' go f-Jj;~ey~ 2123 -:s<j .-&;.z ;y1y rrc&ed recr!p!~-,da.a .b ,&.j.,& .:*3;.. F-Y ' __ ,,,.x+; PC l;ealti: :.2,.i CCI ;et y. tirlr.&g t;1c oy-er at ion c.f sei;a~xl

  2. DIVERSITY OF TYPE Ia SUPERNOVAE IMPRINTED IN CHEMICAL ABUNDANCES

    SciTech Connect (OSTI)

    Tsujimoto, Takuji [National Astronomical Observatory of Japan, Mitaka-shi, Tokyo 181-8588 (Japan); Shigeyama, Toshikazu, E-mail: taku.tsujimoto@nao.ac.jp [Research Center for the Early Universe, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan)

    2012-12-01

    A time delay of Type Ia supernova (SN Ia) explosions hinders the imprint of their nucleosynthesis on stellar abundances. However, some occasional cases give birth to stars that avoid enrichment of their chemical compositions by massive stars and thereby exhibit an SN-Ia-like elemental feature including a very low [Mg/Fe] ( Almost-Equal-To - 1). We highlight the elemental feature of Fe-group elements for two low-Mg/Fe objects detected in nearby galaxies, and propose the presence of a class of SNe Ia that yield the low abundance ratios of [Cr, Mn, Ni/Fe]. Our novel models of chemical evolution reveal that our proposed class of SNe Ia (slow SNe Ia) is associated with ones exploding on a long timescale after their stellar birth and give a significant impact on the chemical enrichment in the Large Magellanic Cloud (LMC). In the Galaxy, on the other hand, this effect is unseen due to the overwhelming enrichment by the major class of SNe Ia that explode promptly (prompt SNe Ia) and eject a large amount of Fe-group elements. This nicely explains the different [Cr, Mn, Ni/Fe] features between the two galaxies as well as the puzzling feature seen in the LMC stars exhibiting very low Ca but normal Mg abundances. Furthermore, the corresponding channel of slow SN Ia is exemplified by performing detailed nucleosynthesis calculations in the scheme of SNe Ia resulting from a 0.8 + 0.6 M{sub Sun} white dwarf merger.

  3. IA Experts Listing 2014 | Department of Energy

    Energy Savers [EERE]

    IA Experts Listing 2014 IA Experts Listing 2014 PDF icon IA Experts Listing January 2014 More Documents & Publications Office of International Affairs Organization Chart PI...

  4. Rolling Hills (IA) | Open Energy Information

    Open Energy Info (EERE)

    Rolling Hills (IA) Jump to: navigation, search Name Rolling Hills (IA) Facility Rolling Hills (IA) Sector Wind energy Facility Type Commercial Scale Wind Facility Status In Service...

  5. Steamboat IA Geothermal Facility | Open Energy Information

    Open Energy Info (EERE)

    IA Geothermal Facility Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Steamboat IA Geothermal Facility General Information Name Steamboat IA Geothermal Facility...

  6. Category:Mason, IA | Open Energy Information

    Open Energy Info (EERE)

    Mason, IA Jump to: navigation, search Go Back to PV Economics By Location Media in category "Mason, IA" The following 16 files are in this category, out of 16 total....

  7. Defining photometric peculiar type Ia supernovae

    SciTech Connect (OSTI)

    González-Gaitán, S.; Pignata, G.; Förster, F.; Gutiérrez, C. P.; Bufano, F.; Galbany, L.; Hamuy, M.; De Jaeger, T.; Hsiao, E. Y.; Phillips, M. M.; Folatelli, G.; Anderson, J. P.

    2014-11-10

    We present a new photometric identification technique for SN 1991bg-like type Ia supernovae (SNe Ia), i.e., objects with light curve characteristics such as later primary maxima and the absence of a secondary peak in redder filters. This method is capable of selecting this sub-group from the normal type Ia population. Furthermore, we find that recently identified peculiar sub-types such as SNe Iax and super-Chandrasekhar SNe Ia have photometric characteristics similar to 91bg-like SNe Ia, namely, the absence of secondary maxima and shoulders at longer wavelengths, and can also be classified with our technique. The similarity of these different SN Ia sub-groups perhaps suggests common physical conditions. This typing methodology permits the photometric identification of peculiar SNe Ia in large upcoming wide-field surveys either to study them further or to obtain a pure sample of normal SNe Ia for cosmological studies.

  8. IA Blog Archive | Department of Energy

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

    Blog Archive IA Blog Archive RSS May 31, 2016 IA Blog Archive Global Energy Leaders Gather in California to Drive Clean Energy Development and Deployment Goal of meetings will be to expand international collaboration in clean energy research, development, demonstration and deployment to combat climate change. May 18, 2016 IA Blog Archive 10 Ways the Clean Energy Ministerial Is Speeding Up the World's Clean Energy Revolution The world needs a lot more clean energy, and fast. Here are 10 ways the

  9. DOE - Office of Legacy Management -- Titus Metals - IA 04

    Office of Legacy Management (LM)

    Titus Metals - IA 04 FUSRAP Considered Sites Site: TITUS METALS ( IA.04 ) Eliminated from consideration under FUSRAP Designated Name: Not Designated Alternate Name: None Location: Waterloo , Iowa IA.04-1 Evaluation Year: 1987 IA.04-2 Site Operations: Extruded uranium billets to produce fuel plates for the Argonaut reactor in June, 1956. IA.04-1 IA.04-2 Site Disposition: Eliminated - Potential for contamination considered remote based on the limited scope of activities at the site and results of

  10. New approaches for modeling type Ia supernovae (Conference) ...

    Office of Scientific and Technical Information (OSTI)

    Type Ia supernovae (SNe Ia) are the largest thermonuclearexplosions in the Universe. Their light output can be seen across greatstances and has led to the discovery that the ...

  11. ASTRONOMY AND ASTROPHYSICS Dark Energy, Type Ia supernovae, radiative

    Office of Scientific and Technical Information (OSTI)

    of Oklahoma Univ. of Oklahoma 79 ASTRONOMY AND ASTROPHYSICS Dark Energy, Type Ia supernovae, radiative transfer, Dark Energy, Type Ia supernovae, radiative transfer, The...

  12. Constraining Cosmic Evolution of Type Ia Supernovae (Journal...

    Office of Scientific and Technical Information (OSTI)

    Constraining Cosmic Evolution of Type Ia Supernovae Citation Details In-Document Search Title: Constraining Cosmic Evolution of Type Ia Supernovae We present the first large-scale...

  13. Type Ia Supernovae Project at NERSC

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

    of star called a white dwarf. The majority of SN Ia explosions occur far away from our galaxy; yet, due to their enormous intrinsic brightness, outshining billions of stars, we can...

  14. IA Blog Archive | Department of Energy

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

    "always be five years away." For four key clean energy technologies, that clean energy future has already arrived. August 21, 2013 IA Blog Archive ActOnClimate: Secretary...

  15. DOE - Office of Legacy Management -- Granite City IL Site - IL...

    Office of Legacy Management (LM)

    Contamination from rubbing off of oxidized uranium during handling. IL.28-3 IL.28-5 ... Aerial photograph of the Granite City, Illinois, Site IL.28-1 - DOE Memo; Wagoner to Price...

  16. Improved Distances to Type Ia Supernovae withMulticolor Light...

    Office of Scientific and Technical Information (OSTI)

    We present an updated version of the Multicolor Light Curve Shape method to measure distances to type Ia supernovae (SN Ia), incorporating new procedures for K-correction and ...

  17. Ideal bandpasses for type Ia supernova cosmology

    SciTech Connect (OSTI)

    Davis, Tamara M.; Schmidt, Brian P.; Kim, Alex G.

    2005-10-24

    To use type Ia supernovae as standard candles for cosmologywe need accurate broadband magnitudes. In practice the observed magnitudemay differ from the ideal magnitude-redshift relationship either throughintrinsic inhomogeneities in the type Ia supernova population or throughobservational error. Here we investigate how we can choose filterbandpasses to reduce the error caused by both these effects. We find thatbandpasses with large integral fluxes and sloping wings are best able tominimise several sources of observational error, and are also leastsensitive to intrinsic differences in type Ia supernovae. The mostimportant feature of a complete filter set for type Ia supernovacosmology is that each bandpass be a redshifted copy of the first. Wedesign practical sets of redshifted bandpasses that are matched totypical high resistivity CCD and HgCdTe infra-red detector sensitivities.These are designed to minimise systematic error in well observedsupernovae, final designs for specific missions should also considersignal-to-noise requirements and observing strategy. In addition wecalculate how accurately filters need to be calibrated in order toachieve the required photometric accuracy of future supernova cosmologyexperiments such as the SuperNova-Acceleration-Probe (SNAP), which is onepossible realisation of the Joint Dark-Energy mission (JDEM). We considerthe effect of possible periodic miscalibrations that may arise from theconstruction of an interference filter.

  18. A threat-based definition of IA- and IA-enabled products.

    SciTech Connect (OSTI)

    Shakamuri, Mayuri; Schaefer, Mark A.; Campbell, Philip LaRoche

    2010-07-01

    This paper proposes a definition of 'IA and IA-enabled products' based on threat, as opposed to 'security services' (i.e., 'confidentiality, authentication, integrity, access control or non-repudiation of data'), as provided by Department of Defense (DoD) Instruction 8500.2, 'Information Assurance (IA) Implementation.' The DoDI 8500.2 definition is too broad, making it difficult to distinguish products that need higher protection from those that do not. As a consequence the products that need higher protection do not receive it, increasing risk. The threat-based definition proposed in this paper solves those problems by focusing attention on threats, thereby moving beyond compliance to risk management. (DoDI 8500.2 provides the definitions and controls that form the basis for IA across the DoD.) Familiarity with 8500.2 is assumed.

  19. A threat-based definition of IA and IA-enabled products.

    SciTech Connect (OSTI)

    Shakamuri, Mayuri; Schaefer, Mark A.; Campbell, Philip LaRoche

    2010-09-01

    This paper proposes a definition of 'IA and IA-enabled products' based on threat, as opposed to 'security services' (i.e., 'confidentiality, authentication, integrity, access control or non-repudiation of data'), as provided by Department of Defense (DoD) Instruction 8500.2, 'Information Assurance (IA) Implementation.' The DoDI 8500.2 definition is too broad, making it difficult to distinguish products that need higher protection from those that do not. As a consequence the products that need higher protection do not receive it, increasing risk. The threat-based definition proposed in this paper solves those problems by focusing attention on threats, thereby moving beyond compliance to risk management. (DoDI 8500.2 provides the definitions and controls that form the basis for IA across the DoD.) Familiarity with 8500.2 is assumed.

  20. IA News Archive | Department of Energy

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

    News Archive IA News Archive RSS July 22, 2016 Energy Department Selects Argonne National Laboratory to Lead U.S. Consortium for New CERC Medium- and Heavy-Duty Truck Technical Track The New Consortium of University, Private Sector and National Laboratory Partners will Advance Collaboration between the U.S. and China on Truck Efficiency Technologies June 10, 2016 Energy Department Invests More than $10 Million in Efficient Lighting Research and Development New projects designed to save consumers

  1. IL FS Ecosmart Ltd | Open Energy Information

    Open Energy Info (EERE)

    Services Product: IL&FS Ecosmart Ltd., a subsidiary of the Infrastructure Leasing & Financial Services (IL&FS) Group, provides environmental services. References: IL&FS...

  2. Type Ia Supernova Hubble Residuals and Host-Galaxy Properties...

    Office of Scientific and Technical Information (OSTI)

    SciTech Connect Search Results Journal Article: Type Ia Supernova Hubble Residuals and ... as distinguished from previous works that use magnitude corrections as a ...

  3. CEPHEID CALIBRATIONS OF MODERN TYPE Ia SUPERNOVAE: IMPLICATIONS...

    Office of Scientific and Technical Information (OSTI)

    CEPHEID CALIBRATIONS OF MODERN TYPE Ia SUPERNOVAE: IMPLICATIONS FOR THE HUBBLE CONSTANT ... Country of Publication: United States Language: English Subject: 79 ASTROPHYSICS, ...

  4. Constraining Cosmic Evolution of Type Ia Supernovae

    SciTech Connect (OSTI)

    Foley, Ryan J.; Filippenko, Alexei V.; Aguilera, C.; Becker, A.C.; Blondin, S.; Challis, P.; Clocchiatti, A.; Covarrubias, R.; Davis, T.M.; Garnavich, P.M.; Jha, S.; Kirshner, R.P.; Krisciunas, K.; Leibundgut, B.; Li, W.; Matheson, T.; Miceli, A.; Miknaitis, G.; Pignata, G.; Rest, A.; Riess, A.G.; /UC, Berkeley, Astron. Dept. /Cerro-Tololo InterAmerican Obs. /Washington U., Seattle, Astron. Dept. /Harvard-Smithsonian Ctr. Astrophys. /Chile U., Catolica /Bohr Inst. /Notre Dame U. /KIPAC, Menlo Park /Texas A-M /European Southern Observ. /NOAO, Tucson /Fermilab /Chile U., Santiago /Harvard U., Phys. Dept. /Baltimore, Space Telescope Sci. /Johns Hopkins U. /Res. Sch. Astron. Astrophys., Weston Creek /Stockholm U. /Hawaii U. /Illinois U., Urbana, Astron. Dept.

    2008-02-13

    We present the first large-scale effort of creating composite spectra of high-redshift type Ia supernovae (SNe Ia) and comparing them to low-redshift counterparts. Through the ESSENCE project, we have obtained 107 spectra of 88 high-redshift SNe Ia with excellent light-curve information. In addition, we have obtained 397 spectra of low-redshift SNe through a multiple-decade effort at Lick and Keck Observatories, and we have used 45 ultraviolet spectra obtained by HST/IUE. The low-redshift spectra act as a control sample when comparing to the ESSENCE spectra. In all instances, the ESSENCE and Lick composite spectra appear very similar. The addition of galaxy light to the Lick composite spectra allows a nearly perfect match of the overall spectral-energy distribution with the ESSENCE composite spectra, indicating that the high-redshift SNe are more contaminated with host-galaxy light than their low-redshift counterparts. This is caused by observing objects at all redshifts with similar slit widths, which corresponds to different projected distances. After correcting for the galaxy-light contamination, subtle differences in the spectra remain. We have estimated the systematic errors when using current spectral templates for K-corrections to be {approx}0.02 mag. The variance in the composite spectra give an estimate of the intrinsic variance in low-redshift maximum-light SN spectra of {approx}3% in the optical and growing toward the ultraviolet. The difference between the maximum-light low and high-redshift spectra constrain SN evolution between our samples to be < 10% in the rest-frame optical.

  5. AIR M A IL

    Office of Legacy Management (LM)

    MEMORlAL DRIVE AIR M A IL ._~ AtFx=b.-zf .7.-i- M r. s. .II. Gown -~ Gentlemen: Re: A.E.C. Contract No. We assume the weight of the 9-l/2" biscuits will:be 107'poutids approximately; i.e. 100 pounds of thorium per biscuit. A four biscuit charge is not feasible because of crucible dimensions, availability, etc. A three biscuit charge will, when molten, fill the proposed crucible half full. This condition is un- desirable because, due to the low heat of fusion of thorium and the

  6. Search for surviving companions in type Ia supernova remnants

    SciTech Connect (OSTI)

    Pan, Kuo-Chuan; Ricker, Paul M.; Taam, Ronald E. E-mail: pmricker@illinois.edu E-mail: taam@asiaa.sinica.edu.tw

    2014-09-01

    The nature of the progenitor systems of type Ia supernovae (SNe Ia) is still unclear. One way to distinguish between the single-degenerate scenario and double-degenerate scenario for their progenitors is to search for the surviving companions (SCs). Using a technique that couples the results from multi-dimensional hydrodynamics simulations with calculations of the structure and evolution of main-sequence- (MS-) and helium-rich SCs, the color and magnitude of MS- and helium-rich SCs are predicted as functions of time. The SC candidates in Galactic type Ia supernova remnants (Ia SNR) and nearby extragalactic Ia SNRs are discussed. We find that the maximum detectable distance of MS SCs (helium-rich SCs) is 0.6-4 Mpc (0.4-16 Mpc), if the apparent magnitude limit is 27 in the absence of extinction, suggesting that the Large and Small Magellanic Clouds and the Andromeda Galaxy are excellent environments in which to search for SCs. However, only five Ia SNRs have been searched for SCs, showing little support for the standard channels in the singe-degenerate scenario. To better understand the progenitors of SNe Ia, we encourage the search for SCs in other nearby Ia SNRs.

  7. THE ULTRAVIOLET BRIGHTEST TYPE Ia SUPERNOVA 2011de

    SciTech Connect (OSTI)

    Brown, Peter J., E-mail: pbrown@physics.tamu.edu [George P. and Cynthia Woods Mitchell Institute for Fundamental Physics and Astronomy, Texas A and M University, Department of Physics and Astronomy, 4242 TAMU, College Station, TX 77843 (United States)

    2014-11-20

    We present and discuss the ultraviolet (UV)/optical photometric light curves and absolute magnitudes of the TypeIa supernova (SN Ia) 2011de from the Swift Ultraviolet/Optical Telescope. We find it to be the UV brightest SN Ia yet observedmore than a factor of 10 brighter than normal SNe Ia in the mid-ultraviolet. We find that the UV/optical brightness and broad light curve evolution can be modeled with additional flux from the shock of the ejecta hitting a relatively large red giant companion separated by 6 10{sup 13} cm. However, the post-maximum behavior of other UV-bright SNe Ia can also be modeled in a similar manner, including objects with UV spectroscopy or pre-maximum photometry which is inconsistent with this model. This suggests that similar UV luminosities can be intrinsic or caused by other forms of shock interaction. The high velocities reported for SN 2011de make it distinct from the UV-bright ''super-Chandrasekhar'' SNe Ia and the NUV-blue group of normal SNe Ia. SN 2011de is an extreme example of the UV variations in SNe Ia.

  8. DOE - Office of Legacy Management -- Bendix Aviation Corp Pioneer Div - IA

    Office of Legacy Management (LM)

    05 Corp Pioneer Div - IA 05 FUSRAP Considered Sites Site: BENDIX AVIATION CORP., PIONEER DIV. (IA.05 ) Eliminated from consideration under FUSRAP Designated Name: Not Designated Alternate Name: Pioneer Division, Bendix Aviation Corporation Bendix Aviation Corporation Bendix Pioneer Division IA.05-1 IA.05-2 IA.05-3 Location: Davenport , Iowa IA.05-1 Evaluation Year: 1990 IA.05-2 IA.05-4 Site Operations: Conducted studies to investigate the feasibility of using sonic cleaning equipment to

  9. Team OptiMN

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

    University of Minnesota Team OptiMN "OptiMN Impact Home" Project Summary Designed to fit on the majority of North Minneapolis infill lots, the OptiMN Impact Home is a collaborative project between the University of Minnesota and Urban Homeworks. The overarching goal was a flexible, high-performance, energy-efficient, and affordable house that can be easily built by Urban Homeworks and purchased by eligible low-income residents of North Minneapolis through the Green Homes North program.

  10. Category:Chicago, IL | Open Energy Information

    Open Energy Info (EERE)

    74 KB SVHospital Chicago IL Commonwealth Edison Co.png SVHospital Chicago IL ... 68 KB SVLargeHotel Chicago IL Commonwealth Edison Co.png SVLargeHotel Chicago I... 75 KB...

  11. A Chandrasekhar mass progenitor for the Type Ia supernova remnant 3C 397 from the enhanced abundances of nickel and manganese

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

    Yamaguchi, Hiroya; Badenes, Carles; Foster, Adam R.; Bravo, Eduardo; Williams, Brian J.; Maeda, Keiichi; Nobukawa, Masayoshi; Eriksen, Kristoffer A.; Brickhouse, Nancy S.; Petre, Robert; et al

    2015-03-12

    Despite decades of intense efforts, many fundamental aspects of Type Ia supernovae (SNe Ia) remain elusive. One of the major open questions is whether the mass of an exploding white dwarf (WD) is close to the Chandrasekhar limit. Here, we report the detection of strong K-shell emission from stable Fe-peak elements in the Suzaku X-ray spectrum of the Type Ia supernova remnant (SNR) 3C 397. The high Ni/Fe and Mn/Fe mass ratios (0.11–0.24 and 0.018–0.033, respectively) in the hot plasma component that dominates the K-shell emission lines indicate a degree of neutronization in the supernova ejecta that can only bemore » achieved by electron capture in the dense cores of exploding WDs with a near-Chandrasekhar mass. This suggests a single-degenerate origin for 3C 397, since Chandrasekhar mass progenitors are expected naturally if the WD accretes mass slowly from a companion. Altogether with other results supporting the double-degenerate scenario, our work adds to the mounting evidence that both progenitor channels make a significant contribution to the SN Ia rate in star-forming galaxies.« less

  12. A Chandrasekhar mass progenitor for the Type Ia supernova remnant 3C 397 from the enhanced abundances of nickel and manganese

    SciTech Connect (OSTI)

    Yamaguchi, Hiroya; Badenes, Carles; Foster, Adam R.; Bravo, Eduardo; Williams, Brian J.; Maeda, Keiichi; Nobukawa, Masayoshi; Eriksen, Kristoffer A.; Brickhouse, Nancy S.; Petre, Robert; Koyama, Katsuji

    2015-03-12

    Despite decades of intense efforts, many fundamental aspects of Type Ia supernovae (SNe Ia) remain elusive. One of the major open questions is whether the mass of an exploding white dwarf (WD) is close to the Chandrasekhar limit. Here, we report the detection of strong K-shell emission from stable Fe-peak elements in the Suzaku X-ray spectrum of the Type Ia supernova remnant (SNR) 3C 397. The high Ni/Fe and Mn/Fe mass ratios (0.11–0.24 and 0.018–0.033, respectively) in the hot plasma component that dominates the K-shell emission lines indicate a degree of neutronization in the supernova ejecta that can only be achieved by electron capture in the dense cores of exploding WDs with a near-Chandrasekhar mass. This suggests a single-degenerate origin for 3C 397, since Chandrasekhar mass progenitors are expected naturally if the WD accretes mass slowly from a companion. Altogether with other results supporting the double-degenerate scenario, our work adds to the mounting evidence that both progenitor channels make a significant contribution to the SN Ia rate in star-forming galaxies.

  13. Category:Springfield, IL | Open Energy Information

    Open Energy Info (EERE)

    Springfield IL Commonwealth Edison Co.png SVQuickServiceRestaura... 75 KB SVFullServiceRestaurant Springfield IL Commonwealth Edison Co.png...

  14. DOE - Office of Legacy Management -- Iowa Army Ammunition Plant - IA 02

    Office of Legacy Management (LM)

    Army Ammunition Plant - IA 02 FUSRAP Considered Sites Iowa Army Ammunition Plant, IA Alternate Name(s): Burlington Ordnance Plant Iowa Ordnance Plant Silas Mason Company IA.02-3 Location: Located in Township 70 North, Range 3 West, Section 32, 5th Principal Meridian, Des Moines County, Burlington, Iowa IA.02-1 IA.02-5 Historical Operations: Assembled nuclear weapons, primarily high explosive components and conducted explosives testing using the high explosive components and depleted uranium. AEC

  15. Characterization of interleukin-15 (IL-15) and the IL-15 receptor complex

    SciTech Connect (OSTI)

    Kennedy, M.K.; Park, L.S.

    1996-05-01

    IL-15 interacts with a heterotrimeric receptor that consists of the {beta} and {gamma} subunits of the IL-2 receptor (IL-2R) as well as a specific, high-affinity IL-15-binding subunit, which is designated IL-15R{alpha}. Since both the {beta} and the {gamma} subunits of the IL-2R are required for signaling by either IL-2 or IL-15, it is not surprising that these cytokines share many activities in vitro. However, the differential expression of these cytokines and the {alpha} chains of their receptors within various tissues and cell types suggests that IL-2 and IL-15 may perform at least partially distinct physiological functions. The production of IL-15 by macrophages, and possibly other cell types, in response to environmental stimuli and infectious agents suggests that IL-15 may play a role in protective immune responses, allograft rejection, and the pathogenesis of autoimmune diseases. 56 refs.

  16. A STUDY OF CARBON FEATURES IN TYPE Ia SUPERNOVA SPECTRA (Journal...

    Office of Scientific and Technical Information (OSTI)

    A STUDY OF CARBON FEATURES IN TYPE Ia SUPERNOVA SPECTRA Citation Details In-Document Search Title: A STUDY OF CARBON FEATURES IN TYPE Ia SUPERNOVA SPECTRA One of the major ...

  17. MN Office of Energy Security | Open Energy Information

    Open Energy Info (EERE)

    MN Office of Energy Security Jump to: navigation, search Name: MN Office of Energy Security Place: St. Paul, MN Website: www.mnofficeofenergysecurity.c References: MN Office of...

  18. IL

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

    Home Locations Contact Us Employee Locator Energy & Climate Secure & Sustainable Energy Future Stationary Power Energy Conversion Efficiency Solar Energy Wind Energy Water Power ...

  19. Il.-'",.'

    Office of Legacy Management (LM)

    ... D&D STATUS REPORT NEW BRUNSWICK LABORATORY NEW JERSEY SITE R. A. Wynveen V. R. Veluri W. H. Smith M. J. Robinet H. J. Moe DECEMBER 1981 INDEX Text D&D ......

  20. FIRST EVIDENCE OF GLOBULAR CLUSTER FORMATION FROM THE EJECTA OF PROMPT TYPE Ia SUPERNOVAE

    SciTech Connect (OSTI)

    Tsujimoto, Takuji [National Astronomical Observatory of Japan, Mitaka-shi, Tokyo 181-8588 (Japan); Bekki, Kenji, E-mail: taku.tsujimoto@nao.ac.jp [ICRAR, M468, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009 (Australia)

    2012-06-01

    Recent spectroscopic observations of globular clusters (GCs) in the Large Magellanic Cloud (LMC) have discovered that one of the intermediate-age GCs, NGC 1718, with [Fe/H] = -0.7 has an extremely low [Mg/Fe] ratio of {approx}-0.9. We propose that NGC 1718 was formed from the ejecta of Type Ia supernovae mixed with very metal-poor ([Fe/H] <-1.3) gas about {approx}2 Gyr ago. The proposed scenario is shown to be consistent with the observed abundances of Fe-group elements such as Cr, Mn, and Ni. In addition, compelling evidence for asymptotic giant branch stars playing a role in chemical enrichment during this GC formation is found. We suggest that the origin of the metal-poor gas is closely associated with efficient gas transfer from the outer gas disk of the Small Magellanic Cloud to the LMC disk. We anticipate that the outer part of the LMC disk contains field stars exhibiting significantly low [Mg/Fe] ratios, formed through the same process as NGC 1718.

  1. Structural and Biophysical Studies of the Human IL-7/IL-7R[alpha] Complex

    SciTech Connect (OSTI)

    McElroy, Craig A.; Dohm, Julie A.; Walsh, Scott T.R.; (OSU); (UPENN)

    2009-03-06

    IL-7 and IL-7R{alpha} bind the {gamma}{sub c} receptor, forming a complex crucial to several signaling cascades leading to the development and homeostasis of T and B cells. We report that the IL-7R{alpha} ectodomain uses glycosylation to modulate its binding constants to IL-7, unlike the other receptors in the {gamma}{sub c} family. IL-7 binds glycosylated IL-7R{alpha} 300-fold more tightly than unglycosylated IL-7R{alpha}, and the enhanced affinity is attributed primarily to an accelerated on rate. Structural comparison of IL-7 in complex to both forms of IL-7R{alpha} reveals that glycosylation does not participate directly in the binding interface. The SCID mutations of IL-7R{alpha} locate outside the binding interface with IL-7, suggesting that the expressed mutations cause protein folding defects in IL-7R{alpha}. The IL-7/IL-7R{alpha} structures provide a window into the molecular recognition events of the IL-7 signaling cascade and provide sites to target for designing new therapeutics to treat IL-7-related diseases.

  2. An Analysis of Department of Defense Instruction 8500.2 'Information Assurance (IA) Implementation.'

    SciTech Connect (OSTI)

    Campbell, Philip LaRoche

    2012-01-01

    The Department of Defense (DoD) provides its standard for information assurance in its Instruction 8500.2, dated February 6, 2003. This Instruction lists 157 'IA Controls' for nine 'baseline IA levels.' Aside from distinguishing IA Controls that call for elevated levels of 'robustness' and grouping the IA Controls into eight 'subject areas' 8500.2 does not examine the nature of this set of controls, determining, for example, which controls do not vary in robustness, how this set of controls compares with other such sets, or even which controls are required for all nine baseline IA levels. This report analyzes (1) the IA Controls, (2) the subject areas, and (3) the Baseline IA levels. For example, this report notes that there are only 109 core IA Controls (which this report refers to as 'ICGs'), that 43 of these core IA Controls apply without variation to all nine baseline IA levels and that an additional 31 apply with variations. This report maps the IA Controls of 8500.2 to the controls in NIST 800-53 and ITGI's CoBIT. The result of this analysis and mapping, as shown in this report, serves as a companion to 8500.2. (An electronic spreadsheet accompanies this report.)

  3. Category:Minneapolis, MN | Open Energy Information

    Open Energy Info (EERE)

    16 total. SVFullServiceRestaurant Minneapolis MN Northern States Power Co (Minnesota) Excel Energy.png SVFullServiceRestauran... 89 KB SVHospital Minneapolis MN Northern States...

  4. Type Ia Supernova Spectral Line Ratios as LuminosityIndicators

    SciTech Connect (OSTI)

    Bongard, Sebastien; Baron, E.; Smadja, G.; Branch, David; Hauschildt, Peter H.

    2005-12-07

    Type Ia supernovae have played a crucial role in thediscovery of the dark energy, via the measurement of their light curvesand the determination of the peak brightness via fitting templates to theobserved lightcurve shape. Two spectroscopic indicators are also known tobe well correlated with peak luminosity. Since the spectroscopicluminosity indicators are obtained directly from observed spectra, theywill have different systematic errors than do measurements usingphotometry. Additionally, these spectroscopic indicators may be usefulfor studies of effects of evolution or age of the SNe~;Ia progenitorpopulation. We present several new variants of such spectroscopicindicators which are easy to automate and which minimize the effects ofnoise. We show that these spectroscopic indicators can be measured byproposed JDEM missions such as snap and JEDI.

  5. Next-Generation Petascale Simulations of Type Ia Supernovae | Argonne

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

    Leadership Computing Facility deflagration to detonation transition model Deflagration to detonation transition model. Min lOng, Dan van Rossum, Sean Couch, George Jordan, Brad Gallagher, Don Lamb, University of Chicago; Michael E. Papka, Argonne National Laboratory/University of Chicago Next-Generation Petascale Simulations of Type Ia Supernovae PI Name: Don Lamb PI Email: lamb@oddjob.uchicago.edu Institution: The University of Chicago Allocation Program: INCITE Allocation Hours at ALCF:

  6. Microsoft PowerPoint - IEEE IAS PES 102313.pptx

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

    DOE's ARRA Smart Grid Program Steve Bossart, Senior Energy Analyst IEEE IAS/PES Pittsburgh Section October 23, 2013 # Topics * OE ARRA Smart Grid Program * OE ARRA Smart Grid Progress * Results and Case Studies * Life After ARRA Smart Grid # DOE OE ARRA Smart Grid Program # American Recovery and Reinvestment Act ($4.5B) * Smart Grid Investment Grants (99 projects) - $3.4 billion Federal; $4.7 billion private sector - > 800 PMUs covering almost 100% of transmission - ~ 8000 distribution

  7. Power-law cosmology, SN Ia, and BAO

    SciTech Connect (OSTI)

    Dolgov, Aleksander; Halenka, Vitali; Tkachev, Igor E-mail: vithal@umich.edu

    2014-10-01

    We revise observational constraints on the class of models of modified gravity which at low redshifts lead to a power-law cosmology. To this end we use available public data on Supernova Ia and on baryon acoustic oscillations. We show that the expansion regime a(t)?t{sup ?} with ? close to 3/2 in a spatially flat universe is a good fit to these data.

  8. DOE - Office of Legacy Management -- Fansteel Metallurgical Corp - IL 16

    Office of Legacy Management (LM)

    Fansteel Metallurgical Corp - IL 16 FUSRAP Considered Sites Site: Fansteel Metallurgical Corp. (IL.16 ) Eliminated from further consideration under FUSRAP Designated Name: Not Designated Alternate Name: None Location: Chicago , Illinois IL.16-1 Evaluation Year: 1987 IL.16-3 Site Operations: Sole producer and supplier of tantalum and columbium metals to the MED. IL.16-1 IL.16-3 Site Disposition: Eliminated - No radioactive materials handled at this site IL.16-2 IL.16-3 Radioactive Materials

  9. Signatures of a companion star in type Ia supernovae

    SciTech Connect (OSTI)

    Maeda, Keiichi; Kutsuna, Masamichi; Shigeyama, Toshikazu

    2014-10-10

    Although type Ia supernovae (SNe Ia) have been used as precise cosmological distance indicators, their progenitor systems remain unresolved. One of the key questions is whether there is a nondegenerate companion star at the time of a thermonuclear explosion of a white dwarf. In this paper, we investigate whether an interaction between the SN ejecta and the companion star may result in observable footprints around the maximum brightness and thereafter, by performing multidimensional radiation transfer simulations based on hydrodynamic simulations of the interaction. We find that such systems result in variations in various observational characteristics due to different viewing directions, and the predicted behaviors (redder and fainter for the companion direction) are the opposite of what were suggested by the previous study. The variations are generally modest and within observed scatters. However, the model predicts trends between some observables different from those observationally derived, so a large sample of SNe Ia with small calibration errors may be used to constrain the existence of such a companion star. The variations in different colors in optical band passes can be mimicked by external extinctions, so such an effect could be a source of scatter in the peak luminosity and derived distance. After the peak, hydrogen-rich materials expelled from the companion will manifest themselves in hydrogen lines, but Hα is extremely difficult to identify. Alternatively, we find that P{sub β} in postmaximum near-infrared spectra can potentially provide a powerful diagnostic.

  10. Type Ia Supernova Hubble Residuals and Host-Galaxy Properties (Journal

    Office of Scientific and Technical Information (OSTI)

    Article) | SciTech Connect Journal Article: Type Ia Supernova Hubble Residuals and Host-Galaxy Properties Citation Details In-Document Search Title: Type Ia Supernova Hubble Residuals and Host-Galaxy Properties Kim et al. (2013) [K13] introduced a new methodology for determining peak- brightness absolute magnitudes of type Ia supernovae from multi-band light curves. We examine the relation between their parameterization of light curves and Hubble residuals, based on photometry synthesized

  11. " Million Housing Units, Final...

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

    9 Water Heating in U.S. Homes in Midwest Region, Divisions, and States, 2009" " Million ... Midwest",,,..."IA, MN, ND, SD" "Water Heating",,,,"IL","MI","WI","IN, ...

  12. THE HYBRID CONe WD + He STAR SCENARIO FOR THE PROGENITORS OF TYPE Ia SUPERNOVAE

    SciTech Connect (OSTI)

    Wang, B.; Meng, X.; Liu, D.-D.; Han, Z.; Liu, Z.-W.

    2014-10-20

    Hybrid CONe white dwarfs (WDs) have been suggested to be possible progenitors of type Ia supernovae (SNe Ia). In this Letter, we systematically studied the hybrid CONe WD + He star scenario for the progenitors of SNe Ia, in which a hybrid CONe WD increases its mass to the Chandrasekhar mass limit by accreting He-rich material from a non-degenerate He star. We obtained the SN Ia birthrates and delay times for this scenario using to a series of detailed binary population synthesis simulations. The SN Ia birthrates for this scenario are ∼0.033-0.539 × 10{sup –3} yr{sup –1}, which roughly accounts for 1%-18% of all SNe Ia. The estimated delay times are ∼28 Myr-178 Myr, which makes these the youngest SNe Ia predicted by any progenitor model so far. We suggest that SNe Ia from this scenario may provide an alternative explanation for type Iax SNe. We also presented some properties of the donors at the point when the WDs reach the Chandrasekhar mass. These properties may be a good starting point for investigating the surviving companions of SNe Ia and for constraining the progenitor scenario studied in this work.

  13. Improved Dark Energy Constraints From ~ 100 New CfA Supernova Type Ia Light

    Office of Scientific and Technical Information (OSTI)

    Curves (Journal Article) | SciTech Connect Improved Dark Energy Constraints From ~ 100 New CfA Supernova Type Ia Light Curves Citation Details In-Document Search Title: Improved Dark Energy Constraints From ~ 100 New CfA Supernova Type Ia Light Curves We combine the CfA3 supernovae Type Ia (SN Ia) sample with samples from the literature to calculate improved constraints on the dark energy equation of state parameter, w. The CfA3 sample is added to the Union set of Kowalski et al. to form the

  14. The Carnegie Supernova Project: Intrinsic colors of type Ia supernovae

    SciTech Connect (OSTI)

    Burns, Christopher R.; Persson, S. E.; Freedman, Wendy L.; Madore, Barry F. [Observatories of the Carnegie Institution for Science, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Stritzinger, Maximilian; Contreras, Carlos [Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C (Denmark); Phillips, M. M.; Hsiao, E. Y.; Boldt, Luis; Campillay, Abdo; Castelln, Sergio; Morrell, Nidia; Salgado, Francisco [Carnegie Institution of Washington, Las Campanas Observatory, Colina El Pino, Casilla 601 (Chile); Folatelli, Gaston [Kavli Institute for the Physics and Mathematics of the Universe, Todai Institutes for Advanced Study, the University of Tokyo, 277-8583 Kashiwa (Japan); Suntzeff, Nicholas B. [George P. and Cynthia Woods Mitchell Institute for Fundamental Physics and Astronomy, Texas A and M University, Department of Physics and Astronomy, College Station, TX 77843 (United States)

    2014-07-01

    We present an updated analysis of the intrinsic colors of Type Ia supernova (SNe Ia) using the latest data release of the Carnegie Supernova Project. We introduce a new light-curve parameter very similar to stretch that is better suited for fast-declining events, and find that these peculiar types can be seen as extensions to the population of 'normal' SNe Ia. With a larger number of objects, an updated fit to the Lira relation is presented along with evidence for a dependence on the late-time slope of the B V light-curves with stretch and color. Using the full wavelength range from u to H band, we place constraints on the reddening law for the sample as a whole and also for individual events/hosts based solely on the observed colors. The photometric data continue to favor low values of R{sub V} , though with large variations from event to event, indicating an intrinsic distribution. We confirm the findings of other groups that there appears to be a correlation between the derived reddening law, R{sub V} , and the color excess, E(B V), such that larger E(B V) tends to favor lower R{sub V} . The intrinsic u-band colors show a relatively large scatter that cannot be explained by variations in R{sub V} or by the Goobar power-law for circumstellar dust, but rather is correlated with spectroscopic features of the supernova and is therefore likely due to metallicity effects.

  15. Grouping normal type Ia supernovae by UV to optical color differences

    SciTech Connect (OSTI)

    Milne, Peter A.; Brown, Peter J.; Roming, Peter W. A.; Bufano, Filomena; Gehrels, Neil

    2013-12-10

    Observations of many Type Ia supernovae (SNe Ia) for multiple epochs per object with the Swift Ultraviolet Optical Telescope instrument have revealed that there exists order to the differences in the UV-optical colors of optically normal supernovae (SNe). We examine UV-optical color curves for 23 SNe Ia, dividing the SNe into four groups, and find that roughly one-third of 'NUV-blue' SNe Ia have bluer UV-optical colors than the larger 'NUV-red' group. Two minor groups are recognized, 'MUV-blue' and 'irregular' SNe Ia. While we conclude that the latter group is a subset of the NUV-red group, containing the SNe with the broadest optical peaks, we conclude that the 'MUV-blue' group is a distinct group. Separating into the groups and accounting for the time evolution of the UV-optical colors lowers the scatter in two NUV-optical colors (e.g., u v and uvw1 v) to the level of the scatter in b v. This finding is promising for extending the cosmological utilization of SNe Ia into the NUV. We generate spectrophotometry of 33 SNe Ia and determine the correct grouping for each. We argue that there is a fundamental spectral difference in the 2900-3500 wavelength range, a region suggested to be dominated by absorption from iron-peak elements. The NUV-blue SNe Ia feature less absorption than the NUV-red SNe Ia. We show that all NUV-blue SNe Ia in this sample also show evidence of unburned carbon in optical spectra, whereas only one NUV-red SN Ia features that absorption line. Every NUV-blue event also exhibits a low gradient of the Si II ?6355 absorption feature. Many NUV-red events also exhibit a low gradient, perhaps suggestive that NUV-blue events are a subset of the larger low-velocity gradient group.

  16. THE BIRTH RATE OF SNe Ia FROM HYBRID CONe WHITE DWARFS

    SciTech Connect (OSTI)

    Meng, Xiangcun [Yunnan Observatories, Chinese Academy of Sciences, Kunming 650011 (China); Podsiadlowski, Philipp, E-mail: xiangcunmeng@ynao.ac.cn [Department of Astronomy, Oxford University, Oxford OX1 3RH (United Kingdom)

    2014-07-10

    Considering the uncertainties of the C-burning rate (CBR) and the treatment of convective boundaries, Chen et al. found that there is a regime where it is possible to form hybrid CONe white dwarfs (WDs), i.e., ONe WDs with carbon-rich cores. As these hybrid WDs can be as massive as 1.30 M {sub ?}, not much mass needs to be accreted for these objects to reach the Chandrasekhar limit and to explode as Type Ia supernovae (SNe Ia). We have investigated their contribution to the overall SN Ia birth rate and found that such SNe Ia tend to be relatively young with typical time delays between 0.1 and 1 Gyr, where some may be as young as 30 Myr. SNe Ia from hybrid CONe WDs may contribute several percent to all SNe Ia, depending on the common-envelope ejection efficiency and the CBR. We suggest that these SNe Ia may produce part of the 2002cx-like SN Ia class.

  17. Type Ia supernova rate studies from the SDSS-II Supernova Study

    SciTech Connect (OSTI)

    Dilday, Benjamin

    2008-08-01

    The author presents new measurements of the type Ia SN rate from the SDSS-II Supernova Survey. The SDSS-II Supernova Survey was carried out during the Fall months (Sept.-Nov.) of 2005-2007 and discovered ~ 500 spectroscopically confirmed SNe Ia with densely sampled (once every ~ 4 days), multi-color light curves. Additionally, the SDSS-II Supernova Survey has discovered several hundred SNe Ia candidates with well-measured light curves, but without spectroscopic confirmation of type. This total, achieved in 9 months of observing, represents ~ 15-20% of the total SNe Ia discovered worldwide since 1885. The author describes some technical details of the SN Survey observations and SN search algorithms that contributed to the extremely high-yield of discovered SNe and that are important as context for the SDSS-II Supernova Survey SN Ia rate measurements.

  18. DOE - Office of Legacy Management -- Kankakee Ordnance Plant - IL 32

    Office of Legacy Management (LM)

    Kankakee Ordnance Plant - IL 32 FUSRAP Considered Sites Site: KANKAKEE ORDNANCE PLANT (IL.32 ) Eliminated from further consideration under FUSRAP Designated Name: Not Designated Alternate Name: None Location: Kankakee , Illinois IL.32-1 Evaluation Year: 1991 IL.32-1 Site Operations: Kankakee Ordnance Plant was cited as a possible location for the disposal of radioactive waste material. There is no indication that any radioactive waste was brought to Kankakee. IL.32-1 IL.32-2 Site Disposition:

  19. DOE - Office of Legacy Management -- Swenson Evaporator Co - IL 23

    Office of Legacy Management (LM)

    Swenson Evaporator Co - IL 23 FUSRAP Considered Sites Site: SWENSON EVAPORATOR CO. (IL.23 ) Eliminated from further consideration under FUSRAP Designated Name: Not Designated Alternate Name: None Location: Harvey , Illinois IL.23-1 Evaluation Year: 1987 IL.23-1 Site Operations: Scheduled a raffinate spray drying test that was later cancelled. IL.23-1 Site Disposition: Eliminated - No indication that radioactive materials were handled at this site IL.23-1 Radioactive Materials Handled: None

  20. DOE - Office of Legacy Management -- Vapofier Corp - IL 25

    Office of Legacy Management (LM)

    Vapofier Corp - IL 25 FUSRAP Considered Sites Site: Vapofier Corp. (IL.25) Eliminated from further consideration under FUSRAP Designated Name: Not Designated Alternate Name: Therm-A-Shield Co. IL.25-1 Location: 11957 Vincennes Avenue , Blue Island , Illinois IL.25-2 Evaluation Year: 1990 IL.25-1 Site Operations: Vapofier Corporation was a subcontractor to the MED during a nine month period in 1944. There is no indication that radioactive materials were handled. IL.25-1 Site Disposition:

  1. DOE - Office of Legacy Management -- Podbeilniac Corp - IL 22

    Office of Legacy Management (LM)

    Podbeilniac Corp - IL 22 FUSRAP Considered Sites Site: PODBEILNIAC CORP. (IL.22) Eliminated from consideration under FUSRAP Designated Name: Not Designated Alternate Name: None Location: Chicago , Illinois IL.22-1 Evaluation Year: 1990 IL.22-2 Site Operations: MED used equipment for a uranium extraction experiment in 1957. IL.22-1 Site Disposition: Eliminated - Potential for contamination considered remote due to limited scope of activities performed at the site IL.22-2 IL.22-3 IL.22-4

  2. On silicon group elements ejected by supernovae type IA

    SciTech Connect (OSTI)

    De, Soma; Timmes, F. X. [School of Earth and Space Exploration, Arizona State University, Tempe, AZ (United States); Brown, Edward F. [Joint Institute for Nuclear Astrophysics, University of Notre Dame, IN 46556 (United States); Calder, Alan C. [Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY (United States); Townsley, Dean M. [Department of Physics and Astronomy, The University of Alabama, Tuscaloosa, AL (United States); Athanassiadou, Themis [Swiss National Supercomputing Centre, Via Trevano 131, 6900 Lugano (Switzerland); Chamulak, David A. [Physics Division, Argonne National Laboratory, Argonne, IL (United States); Hawley, Wendy [Laboratoire d'Astrophysique de Marseille, Marseille cedex 13 F-13388 (France); Jack, Dennis, E-mail: somad@asu.edu [Departamento de Astronoma, Universidad de Guanajuato, Apartado Postal 144, 36000 Guanajuato (Mexico)

    2014-06-01

    There is evidence that the peak brightness of a Type Ia supernova is affected by the electron fraction Y {sub e} at the time of the explosion. The electron fraction is set by the aboriginal composition of the white dwarf and the reactions that occur during the pre-explosive convective burning. To date, determining the makeup of the white dwarf progenitor has relied on indirect proxies, such as the average metallicity of the host stellar population. In this paper, we present analytical calculations supporting the idea that the electron fraction of the progenitor systematically influences the nucleosynthesis of silicon group ejecta in Type Ia supernovae. In particular, we suggest the abundances generated in quasi-nuclear statistical equilibrium are preserved during the subsequent freeze-out. This allows potential recovery of Y {sub e} at explosion from the abundances recovered from an observed spectra. We show that measurement of {sup 28}Si, {sup 32}S, {sup 40}Ca, and {sup 54}Fe abundances can be used to construct Y {sub e} in the silicon-rich regions of the supernovae. If these four abundances are determined exactly, they are sufficient to recover Y {sub e} to 6%. This is because these isotopes dominate the composition of silicon-rich material and iron-rich material in quasi-nuclear statistical equilibrium. Analytical analysis shows the {sup 28}Si abundance is insensitive to Y {sub e}, the {sup 32}S abundance has a nearly linear trend with Y {sub e}, and the {sup 40}Ca abundance has a nearly quadratic trend with Y {sub e}. We verify these trends with post-processing of one-dimensional models and show that these trends are reflected in the model's synthetic spectra.

  3. CfA3: 185 TYPE Ia SUPERNOVA LIGHT CURVES FROM THE CfA

    SciTech Connect (OSTI)

    Hicken, Malcolm; Challis, Peter; Kirshner, Robert P.; Bakos, Gaspar; Berlind, Perry; Brown, Warren R.; Caldwell, Nelson; Calkins, Mike; Cho, Richard; Contreras, Maria; Jha, Saurabh; Matheson, Tom; Modjaz, Maryam; Rest, Armin; Michael Wood-Vasey, W.; Barton, Elizabeth J.; Bragg, Ann; Briceno, Cesar; Ciupik, Larry; Dendy, Kristi-Concannon E-mail: kirshner@cfa.harvard.edu

    2009-07-20

    We present multiband photometry of 185 type-Ia supernovae (SNe Ia), with over 11,500 observations. These were acquired between 2001 and 2008 at the F. L. Whipple Observatory of the Harvard-Smithsonian Center for Astrophysics (CfA). This sample contains the largest number of homogeneously observed and reduced nearby SNe Ia (z {approx}< 0.08) published to date. It more than doubles the nearby sample, bringing SN Ia cosmology to the point where systematic uncertainties dominate. Our natural system photometry has a precision of {approx}<0.02 mag in BVRIr'i' and {approx}<0.04 mag in U for points brighter than 17.5 mag. We also estimate a systematic uncertainty of 0.03 mag in our SN Ia standard system BVRIr'i' photometry and 0.07 mag for U. Comparisons of our standard system photometry with published SN Ia light curves and comparison stars, where available for the same SN, reveal agreement at the level of a few hundredths mag in most cases. We find that 1991bg-like SNe Ia are sufficiently distinct from other SNe Ia in their color and light-curve-shape/luminosity relation that they should be treated separately in light-curve/distance fitter training samples. The CfA3 sample will contribute to the development of better light-curve/distance fitters, particularly in the few dozen cases where near-infrared photometry has been obtained and, together, can help disentangle host-galaxy reddening from intrinsic supernova color, reducing the systematic uncertainty in SN Ia distances due to dust.

  4. DOE - Office of Legacy Management -- Armour Research Foundation - IL 17

    Office of Legacy Management (LM)

    Research Foundation - IL 17 FUSRAP Considered Sites Site: Armour Research Foundation of the Illinois Institute of Technology (IL.17 ) Eliminated from further consideration under FUSRAP Designated Name: Not Designated Alternate Name: Illinois Institute of Technology IL.17-1 Location: Technological Center, 10 West 35th Street , Chicago , Illinois IL.17-1 Evaluation Year: 1985 IL.17-3 Site Operations: Facility operated a research reactor and conducted associated research for the AEC beginning in

  5. DOE - Office of Legacy Management -- Blockson Chemical Co - IL 07

    Office of Legacy Management (LM)

    Blockson Chemical Co - IL 07 FUSRAP Considered Sites Site: Blockson Chemical Co. (IL.07) Eliminated from consideration under FUSRAP - Referred to US EPA Region V and the State of Illinios Designated Name: Not Designated Alternate Name: Olin Corporation IL.07-1 Location: Patterson Road , Joliet , Illinois IL.07-2 Evaluation Year: 1985 IL.07-1 Site Operations: Process development studies and pilot plant testing of uranium recovery from phosphoric acid during the 1950s. Site Disposition: Eliminated

  6. DOE - Office of Legacy Management -- Kaiser Aluminum Corp - IL 19

    Office of Legacy Management (LM)

    Kaiser Aluminum Corp - IL 19 FUSRAP Considered Sites Site: KAISER ALUMINUM CORP. (IL.19 ) Eliminated from further consideration under FUSRAP Designated Name: Not Designated Alternate Name: None Location: Dolton , Illinois IL.19-2 Evaluation Year: 1987 IL.19-2 Site Operations: Performed limited duration work extruding uranium billets into three CP-5 fuel elements, circa 1959. IL.19-2 Site Disposition: Eliminated - Potential for contamination considered remote due to limited scope of activities

  7. DOE - Office of Legacy Management -- Precision Extrusion Co - IL 20

    Office of Legacy Management (LM)

    Precision Extrusion Co - IL 20 FUSRAP Considered Sites Site: PRECISION EXTRUSION CO. (IL.20) Eliminated from further consideration under FUSRAP Designated Name: Not Designated Alternate Name: None Location: 720 East Green Avenue , Bensenville , Illinois IL.20-1 Evaluation Year: 1987 IL.20-2 Site Operations: 1956-1959, metal fabrication - extruded uranium billets. IL.20-1 Site Disposition: Eliminated - Potential for contamination considered remote based on limited quantities of materials handled

  8. Mn4+ emission in pyrochlore oxides

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

    Du, Mao-Hua

    2015-01-01

    For the existing Mn4+ activated red phosphors have relatively low emission energies (or long emission wavelengths) and are therefore inefficient for general lighting. Density functional calculations are performed to study Mn4+ emission in rare-earth hafnate, zirconate, and stannate pyrochlore oxides (RE2Hf2O7, RE2Zr2O7, and RE2Sn2O7). We show how the different sizes of the RE3+ cation in these pyrochlores affect the local structure of the distorted MnO6 octahedron, the Mn–O hybridization, and the Mn4+ emission energy. The Mn4+ emission energies of many pyrochlores are found to be higher than those currently known for Mn4+ doped oxides and should be closer to thatmore » of Y2O3:Eu3+ (the current commercial red phosphor for fluorescent lighting). The O–Mn–O bond angle distortion in a MnO6 octahedron is shown to play an important role in weakening Mn–O hybridization and consequently increasing the Mn4+ emission energy. Our result shows that searching for materials that allow significant O–Mn–O bond angle distortion in a MnO6 octahedron is an effective approach to find new Mn4+ activated red phosphors with potential to replace the relatively expensive Y2O3:Eu3+ phosphor.« less

  9. Type Ia supernovae yielding distances with 3-4% precision (Journal...

    Office of Scientific and Technical Information (OSTI)

    A paper copy of this document is also available for sale to the public from the National Technical Information Service, Springfield, VA at www.ntis.gov. The luminosities of Type Ia ...

  10. File:USDA-CE-Production-GIFmaps-IA.pdf | Open Energy Information

    Open Energy Info (EERE)

    IA.pdf Jump to: navigation, search File File history File usage Iowa Ethanol Plant Locations Size of this preview: 776 600 pixels. Full resolution (1,650 1,275 pixels,...

  11. Low Mach Number Modeling of Type Ia Supernovae

    SciTech Connect (OSTI)

    Almgren, Ann S.; Bell, John B.; Rendleman, Charles A.; Zingale,Michael

    2005-08-05

    We introduce a low Mach number equation set for the large-scale numerical simulation of carbon-oxygen white dwarfs experiencing a thermonuclear deflagration. Since most of the interesting physics in a Type Ia supernova transpires at Mach numbers from 0.01 to 0.1, such an approach enables both a considerable increase in accuracy and savings in computer time compared with frequently used compressible codes. Our equation set is derived from the fully compressible equations using low Mach number asymptotics, but without any restriction on the size of perturbations in density or temperature. Comparisons with simulations that use the fully compressible equations validate the low Mach number model in regimes where both are applicable. Comparisons to simulations based on the more traditional an elastic approximation also demonstrate the agreement of these models in the regime for which the anelastic approximation is valid. For low Mach number flows with potentially finite amplitude variations in density and temperature, the low Mach number model overcomes the limitations of each of the more traditional models and can serve as the basis for an accurate and efficient simulation tool.

  12. Cosmological parameter uncertainties from SALT-II type Ia supernova light curve models

    SciTech Connect (OSTI)

    Mosher, J.; Sako, M. [Department of Physics and Astronomy, University of Pennsylvania, 209 South 33rd Street, Philadelphia, PA 19104 (United States); Guy, J.; Astier, P.; Betoule, M.; El-Hage, P.; Pain, R.; Regnault, N. [LPNHE, CNRS/IN2P3, Universit Pierre et Marie Curie Paris 6, Universi Denis Diderot Paris 7, 4 place Jussieu, F-75252 Paris Cedex 05 (France); Kessler, R.; Frieman, J. A. [Kavli Institute for Cosmological Physics, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637 (United States); Marriner, J. [Center for Particle Astrophysics, Fermi National Accelerator Laboratory, P.O. Box 500, Batavia, IL 60510 (United States); Biswas, R.; Kuhlmann, S. [Argonne National Laboratory, 9700 South Cass Avenue, Lemont, IL 60439 (United States); Schneider, D. P., E-mail: kessler@kicp.chicago.edu [Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802 (United States)

    2014-09-20

    We use simulated type Ia supernova (SN Ia) samples, including both photometry and spectra, to perform the first direct validation of cosmology analysis using the SALT-II light curve model. This validation includes residuals from the light curve training process, systematic biases in SN Ia distance measurements, and a bias on the dark energy equation of state parameter w. Using the SN-analysis package SNANA, we simulate and analyze realistic samples corresponding to the data samples used in the SNLS3 analysis: ?120 low-redshift (z < 0.1) SNe Ia, ?255 Sloan Digital Sky Survey SNe Ia (z < 0.4), and ?290 SNLS SNe Ia (z ? 1). To probe systematic uncertainties in detail, we vary the input spectral model, the model of intrinsic scatter, and the smoothing (i.e., regularization) parameters used during the SALT-II model training. Using realistic intrinsic scatter models results in a slight bias in the ultraviolet portion of the trained SALT-II model, and w biases (w {sub input} w {sub recovered}) ranging from 0.005 0.012 to 0.024 0.010. These biases are indistinguishable from each other within the uncertainty; the average bias on w is 0.014 0.007.

  13. CRAD, NNSA - Maintenance (MN) | Department of Energy

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

    NNSA - Maintenance (MN) CRAD, NNSA - Maintenance (MN) CRAD for Maintenance (MN). Criteria Review and Approach Documents (CRADs) that can be used to conduct a well-organized and thorough assessment of elements of safety and health programs. CRADs consist of a Performance Objective that identifies the expectation(s) or requirement(s) to be verified, which reflect the complete scope of the assessment; Criteria that provide specifics by which the performance objectives are measured, including

  14. Curcumin blocks interleukin (IL)-2 signaling in T-lymphocytes by inhibiting IL-2 synthesis, CD25 expression, and IL-2 receptor signaling

    SciTech Connect (OSTI)

    Forward, Nicholas A.; Conrad, David M.; Power Coombs, Melanie R.; Doucette, Carolyn D.; Furlong, Suzanne J.; Lin, Tong-Jun; Department of Pediatrics, Dalhousie University, Halifax, Nova Scotia ; Hoskin, David W.

    2011-04-22

    Highlights: {yields} Curcumin inhibits CD4{sup +} T-lymphocyte proliferation. {yields} Curcumin inhibits interleukin-2 (IL-2) synthesis and CD25 expression by CD4{sup +} T-lymphocytes. {yields} Curcumin interferes with IL-2 receptor signaling by inhibiting JAK3 and STAT5 phosphorylation. {yields} IL-2-dependent regulatory T-lymphocyte function and Foxp3 expression is downregulated by curcumin. -- Abstract: Curcumin (diferulomethane) is the principal curcuminoid in the spice tumeric and a potent inhibitor of activation-induced T-lymphocyte proliferation; however, the molecular basis of this immunosuppressive effect has not been well studied. Here we show that micromolar concentrations of curcumin inhibited DNA synthesis by mouse CD4{sup +} T-lymphocytes, as well as interleukin-2 (IL-2) and CD25 ({alpha} chain of the high affinity IL-2 receptor) expression in response to antibody-mediated cross-linking of CD3 and CD28. Curcumin acted downstream of protein kinase C activation and intracellular Ca{sup 2+} release to inhibit I{kappa}B phosphorylation, which is required for nuclear translocation of the transcription factor NF{kappa}B. In addition, IL-2-dependent DNA synthesis by mouse CTLL-2 cells, but not constitutive CD25 expression, was impaired in the presence of curcumin, which demonstrated an inhibitory effect on IL-2 receptor (IL-2R) signaling. IL-2-induced phosphorylation of STAT5A and JAK3, but not JAK1, was diminished in the presence of curcumin, indicating inhibition of critical proximal events in IL-2R signaling. In line with the inhibitory action of curcumin on IL-2R signaling, pretreatment of CD4{sup +}CD25{sup +} regulatory T-cells with curcumin downregulated suppressor function, as well as forkhead box p3 (Foxp3) expression. We conclude that curcumin inhibits IL-2 signaling by reducing available IL-2 and high affinity IL-2R, as well as interfering with IL-2R signaling.

  15. DOE - Office of Legacy Management -- Heavy Minerals Inc - IL 14

    Office of Legacy Management (LM)

    Heavy Minerals Inc - IL 14 FUSRAP Considered Sites Site: Heavy Minerals, Inc. ( IL.14 ) Eliminated from consideration under FUSRAP Designated Name: Not Designated Alternate Name: W.R. Grace Company IL.14-1 Location: 836 South Michigan Avenue , Chicago , Illinois IL.14-2 Evaluation Year: 1990 IL.14-1 Site Operations: Submitted a proposal to supply thorium hydroxide to the AEC; no indication that the bid was accepted. IL.14-2 Site Disposition: Eliminated - No indication of work done with

  16. DOE - Office of Legacy Management -- Elk River Reactor - MN 01

    Office of Legacy Management (LM)

    Elk River Reactor - MN 01 FUSRAP Considered Sites Site: Elk River Reactor (MN.01 ) Eliminated from consideration under FUSRAP - Reactor was dismantled and decommissioned by 1974 Designated Name: Not Designated Alternate Name: None Location: Elk River , Minnesota MN.01-1 Evaluation Year: 1985 MN.01-1 Site Operations: Boiling water reactor demonstration, research and development program MN.01-1 Site Disposition: Eliminated MN.01-1 Radioactive Materials Handled: None Indicated Primary Radioactive

  17. DOE - Office of Legacy Management -- Chicago North IL Site -...

    Office of Legacy Management (LM)

    IL.05-1 - DOE Letter; Whitman to Wallo; Subject: Authority decisions regarding several sites; October 28, 1985 IL.05-2 - DOE Letter; DeLaney to Holesinger; Subject: Radiological ...

  18. DOE - Office of Legacy Management -- Rock Island Arsenal - IL...

    Office of Legacy Management (LM)

    to DOD Designated Name: Not Designated Alternate Name: None Location: Rock Island , Illinois IL.09-1 Evaluation Year: 1987 IL.09-2 Site Operations: Site located on a DOD ...

  19. Il Woong Jung | Argonne National Laboratory

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

    Il Woong Jung Assistant Scientist Education Ph.D., Electrical Engineering, Stanford University Research Summary Research interests are in photonic applications for micro- and nano-mechanical devices. Current research focuses on the manipulation of light-matter interaction at the nanoscale, specifically using micro- and nano-mechanical devices to control the optical properties of photonic nanostructures. The aim is to integrate optical nanostructures and nanomechanical devices to create novel

  20. DOE - Office of Legacy Management -- International Register - IL 15

    Office of Legacy Management (LM)

    Register - IL 15 Site ID (CSD Index Number): IL.15 Site Name: International Register Site Summary: Site Link: External Site Link: Alternate Name(s): Intermatic Inc. Alternate Name Documents: Location: Chicago, Illinois Location Documents: IL.15-1 Historical Operations (describe contaminants): Limited testing of centerless grinding techniques for uranium metal for the AEC. Historical Operations Documents: IL.15-2 Eligibility Determination: Eliminated - Potential for contamination considered

  1. Magnetostructural phase transformations in Tb 1-x Mn 2 (Journal...

    Office of Scientific and Technical Information (OSTI)

    phase transformations in Tb 1-x Mn 2 Citation Details In-Document Search Title: Magnetostructural phase transformations in Tb 1-x Mn 2 Magnetism and phase transformations ...

  2. Type Ia supernovae from merging white dwarfs. II. Post-merger detonations

    SciTech Connect (OSTI)

    Raskin, Cody; Kasen, Daniel; Moll, Rainer; Woosley, Stan; Schwab, Josiah

    2014-06-10

    Merging carbon-oxygen (CO) white dwarfs are a promising progenitor system for Type Ia supernovae (SNe Ia), but the underlying physics and timing of the detonation are still debated. If an explosion occurs after the secondary star is fully disrupted, the exploding primary will expand into a dense CO medium that may still have a disk-like structure. This interaction will decelerate and distort the ejecta. Here we carry out multidimensional simulations of 'tamped' SN Ia models, using both particle and grid-based codes to study the merger and explosion dynamics and a radiative transfer code to calculate synthetic spectra and light curves. We find that post-merger explosions exhibit an hourglass-shaped asymmetry, leading to strong variations in the light curves with viewing angle. The two most important factors affecting the outcome are the scale height of the disk, which depends sensitively on the binary mass ratio, and the total {sup 56}Ni yield, which is governed by the central density of the remnant core. The synthetic broadband light curves rise and decline very slowly, and the spectra generally look peculiar, with weak features from intermediate mass elements but relatively strong carbon absorption. We also consider the effects of the viscous evolution of the remnant and show that a longer time delay between merger and explosion probably leads to larger {sup 56}Ni yields and more symmetrical remnants. We discuss the relevance of this class of aspherical 'tamped' SN Ia for explaining the class of 'super-Chandrasekhar' SN Ia.

  3. Magnetocrystalline anisotropy in UMn<mn>2mn>Ge>2mn> and related Mn-based actinide ferromagnets

    SciTech Connect (OSTI)

    Parker, David S.; Ghimire, Nirmal; Singleton, John; Thompson, J. D.; Bauer, Eric D.; Baumbach, Ryan; Mandrus, David; Li, Ling; Singh, David J.

    2015-05-04

    We present magnetization isotherms in pulsed magnetic fields up to 62 Tesla, supported by first principles calculations, demonstrating a huge uniaxial magnetocrystalline anisotropy energy - approximately 20 MJ/m3 - in UMn<mn>2mn>Ge>2mn>. This large anisotropy results from the extremely strong spin-orbit coupling affecting the uranium 5 f electrons, which in the calculations exhibit a substantial orbital moment exceeding 2 μB. Finally, we also find from theoretical calculations that a number of isostructural Mn-actinide compounds are expected to have similarly large anisotropy.

  4. DOE - Office of Legacy Management -- Crane Co - IL 13

    Office of Legacy Management (LM)

    Crane Co - IL 13 FUSRAP Considered Sites Site: Crane Co. (IL.13 ) Eliminated from consideration under FUSRAP Designated Name: Not Designated Alternate Name: None Location: Chicago , Illinois IL.13-2 Evaluation Year: 1987 IL.13-2 Site Operations: MED activities during late-1940s to early/mid-1950s included the development of valves and possibly the use of test quantities of normal uranium in the development process. IL.13-4 Site Disposition: Eliminated - Potential for contamination remote due to

  5. Ultraviolet observations of Super-Chandrasekhar mass type Ia supernova candidates with swift UVOT

    SciTech Connect (OSTI)

    Brown, Peter J.; Smitka, Michael T.; Krisciunas, Kevin; Wang, Lifan; Kuin, Paul; De Pasquale, Massimiliano; Scalzo, Richard; Holland, Stephen; Milne, Peter

    2014-05-20

    Among Type Ia supernovae (SNe Ia), a class of overluminous objects exist whose ejecta mass is inferred to be larger than the canonical Chandrasekhar mass. We present and discuss the UV/optical photometric light curves, colors, absolute magnitudes, and spectra of three candidate Super-Chandrasekhar mass SNe—2009dc, 2011aa, and 2012dn—observed with the Swift Ultraviolet/Optical Telescope. The light curves are at the broad end for SNe Ia, with the light curves of SN 2011aa being among the broadest ever observed. We find all three to have very blue colors which may provide a means of excluding these overluminous SNe from cosmological analysis, though there is some overlap with the bluest of 'normal' SNe Ia. All three are overluminous in their UV absolute magnitudes compared to normal and broad SNe Ia, but SNe 2011aa and 2012dn are not optically overluminous compared to normal SNe Ia. The integrated luminosity curves of SNe 2011aa and 2012dn in the UVOT range (1600-6000 Å) are only half as bright as SN 2009dc, implying a smaller {sup 56}Ni yield. While it is not enough to strongly affect the bolometric flux, the early time mid-UV flux makes a significant contribution at early times. The strong spectral features in the mid-UV spectra of SNe 2009dc and 2012dn suggest a higher temperature and lower opacity to be the cause of the UV excess rather than a hot, smooth blackbody from shock interaction. Further work is needed to determine the ejecta and {sup 56}Ni masses of SNe 2011aa and 2012dn and to fully explain their high UV luminosities.

  6. DOE - Office of Legacy Management -- GSA 39th Street Warehouse - IL 02

    Office of Legacy Management (LM)

    GSA 39th Street Warehouse - IL 02 FUSRAP Considered Sites Site: GSA 39TH STREET WAREHOUSE (IL.02 ) Eliminated from consideration under FUSRAP Designated Name: Not Designated Alternate Name: None Location: 1716 West Pershing Road , Chicago , Illinois IL.02-1 Evaluation Year: 1985 IL.02-2 IL.02-3 Site Operations: Stored radioactive materials. IL.02-1 IL.02-2 Site Disposition: Eliminated - Radiation levels below criteria IL.02-1 Radioactive Materials Handled: Yes Primary Radioactive Materials

  7. Magnetic coupling in ferromagnetic semiconductor (Ga,Mn)As/(Al,Ga,Mn)As bilayers

    SciTech Connect (OSTI)

    Wang, M.; Wadley, P.; Campion, R. P.; Rushforth, A. W.; Edmonds, K. W.; Gallagher, B. L.; Charlton, T. R.; Kinane, C. J.; Langridge, S.

    2015-08-07

    We report on a study of ferromagnetic semiconductor (Ga,Mn)As/(Al,Ga,Mn)As bilayers using magnetometry and polarized neutron reflectivity (PNR). From depth-resolved characterization of the magnetic structure obtained by PNR, we concluded that the (Ga,Mn)As and (Al,Ga,Mn)As layers have in-plane and perpendicular-to-plane magnetic easy axes, respectively, with weak interlayer coupling. Therefore, the layer magnetizations align perpendicular to each other under low magnetic fields and parallel at high fields.

  8. SSL Demonstration: Bridge Lighting, Minneapolis, MN

    SciTech Connect (OSTI)

    2014-10-01

    DOE Solid-State Lighting GATEWAY summary brief for Phase II report on the longer-term performance of LED lighting installed in 2008 on the I-35W Bridge in Minneapolis, MN.

  9. High Mn austenitic stainless steel

    DOE Patents [OSTI]

    Yamamoto, Yukinori [Oak Ridge, TN; Santella, Michael L [Knoxville, TN; Brady, Michael P [Oak Ridge, TN; Maziasz, Philip J [Oak Ridge, TN; Liu, Chain-tsuan [Knoxville, TN

    2010-07-13

    An austenitic stainless steel alloy includes, in weight percent: >4 to 15 Mn; 8 to 15 Ni; 14 to 16 Cr; 2.4 to 3 Al; 0.4 to 1 total of at least one of Nb and Ta; 0.05 to 0.2 C; 0.01 to 0.02 B; no more than 0.3 of combined Ti+V; up to 3 Mo; up to 3 Co; up to 1W; up to 3 Cu; up to 1 Si; up to 0.05 P; up to 1 total of at least one of Y, La, Ce, Hf, and Zr; less than 0.05 N; and base Fe, wherein the weight percent Fe is greater than the weight percent Ni, and wherein the alloy forms an external continuous scale including alumina, nanometer scale sized particles distributed throughout the microstructure, the particles including at least one of NbC and TaC, and a stable essentially single phase FCC austenitic matrix microstructure that is essentially delta-ferrite-free and essentially BCC-phase-free.

  10. Strong near-infrared carbon in the Type Ia supernova iPTF13ebh

    SciTech Connect (OSTI)

    Hsiao, E. Y.; Burns, C. R.; Contreras, C.; Höflich, P.; Sand, D.; Marion, G. H.; Phillips, M. M.; Stritzinger, M.; González-Gaitán, S.; Mason, R. E.; Folatelli, G.; Parent, E.; Gall, C.; Amanullah, R.; Anupama, G. C.; Arcavi, I.; Banerjee, D. P. K.; Beletsky, Y.; Blanc, G. A.; Bloom, J. S.; Brown, P. J.; Campillay, A.; Cao, Y.; De Cia, A.; Diamond, T.; Freedman, W. L.; Gonzalez, C.; Goobar, A.; Holmbo, S.; Howell, D. A.; Johansson, J.; Kasliwal, M. M.; Kirshner, R. P.; Krisciunas, K.; Kulkarni, S. R.; Maguire, K.; Milne, P. A.; Morrell, N.; Nugent, P. E.; Ofek, E. O.; Osip, D.; Palunas, P.; Perley, D. A.; Persson, S. E.; Piro, A. L.; Rabus, M.; Roth, M.; Schiefelbein, J. M.; Srivastav, S.; Sullivan, M.; Suntzeff, N. B.; Surace, J.; Woźniak, P. R.; Yaron, O.

    2015-05-22

    We present near-infrared (NIR) time-series spectroscopy, as well as complementary ultraviolet (UV), optical, and NIR data, of the Type Ia supernova (SN Ia) iPTF13ebh, which was discovered within two days from the estimated time of explosion. The first NIR spectrum was taken merely 2.3 days after explosion and may be the earliest NIR spectrum yet obtained of a SN Ia. The most striking features in the spectrum are several NIR C I lines, and the C Iλ1.0693 μm line is the strongest ever observed in a SN Ia. Interestingly, no strong optical C II counterparts were found, even though the optical spectroscopic time series began early and is densely cadenced. Except at the very early epochs, within a few days from the time of explosion, we show that the strong NIR C I compared to the weaker optical C II appears to be general in SNe Ia. iPTF13ebh is a fast decliner with Δm15(B) = 1.79 ± 0.01, and its absolute magnitude obeys the linear part of the width-luminosity relation. It is therefore categorized as a “transitional” event, on the fast-declining end of normal SNe Ia as opposed to subluminous/91bg-like objects. iPTF13ebh shows NIR spectroscopic properties that are distinct from both the normal and subluminous/91bg-like classes, bridging the observed characteristics of the two classes. These NIR observations suggest that composition and density of the inner core are similar to that of 91bg-like events, and that it has a deep-reaching carbon burning layer that is not observed in more slowly declining SNe Ia. Furthermore, there is also a substantial difference between the explosion times inferred from the early-time light curve and the velocity evolution of the Si II λ0.6355 μm line, implying a long dark phase of ~4 days.

  11. Strong near-infrared carbon in the Type Ia supernova iPTF13ebh

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

    Hsiao, E. Y.; Burns, C. R.; Contreras, C.; Höflich, P.; Sand, D.; Marion, G. H.; Phillips, M. M.; Stritzinger, M.; González-Gaitán, S.; Mason, R. E.; et al

    2015-05-22

    We present near-infrared (NIR) time-series spectroscopy, as well as complementary ultraviolet (UV), optical, and NIR data, of the Type Ia supernova (SN Ia) iPTF13ebh, which was discovered within two days from the estimated time of explosion. The first NIR spectrum was taken merely 2.3 days after explosion and may be the earliest NIR spectrum yet obtained of a SN Ia. The most striking features in the spectrum are several NIR C I lines, and the C Iλ1.0693 μm line is the strongest ever observed in a SN Ia. Interestingly, no strong optical C II counterparts were found, even though themore » optical spectroscopic time series began early and is densely cadenced. Except at the very early epochs, within a few days from the time of explosion, we show that the strong NIR C I compared to the weaker optical C II appears to be general in SNe Ia. iPTF13ebh is a fast decliner with Δm15(B) = 1.79 ± 0.01, and its absolute magnitude obeys the linear part of the width-luminosity relation. It is therefore categorized as a “transitional” event, on the fast-declining end of normal SNe Ia as opposed to subluminous/91bg-like objects. iPTF13ebh shows NIR spectroscopic properties that are distinct from both the normal and subluminous/91bg-like classes, bridging the observed characteristics of the two classes. These NIR observations suggest that composition and density of the inner core are similar to that of 91bg-like events, and that it has a deep-reaching carbon burning layer that is not observed in more slowly declining SNe Ia. Furthermore, there is also a substantial difference between the explosion times inferred from the early-time light curve and the velocity evolution of the Si II λ0.6355 μm line, implying a long dark phase of ~4 days.« less

  12. Strong near-infrared carbon in the Type Ia supernova iPTF13ebh

    SciTech Connect (OSTI)

    Hsiao, E. Y.; Burns, C. R.; Contreras, C.; Hflich, P.; Sand, D.; Marion, G. H.; Phillips, M. M.; Stritzinger, M.; Gonzlez-Gaitn, S.; Mason, R. E.; Folatelli, G.; Parent, E.; Gall, C.; Amanullah, R.; Anupama, G. C.; Arcavi, I.; Banerjee, D. P. K.; Beletsky, Y.; Blanc, G. A.; Bloom, J. S.; Brown, P. J.; Campillay, A.; Cao, Y.; De Cia, A.; Diamond, T.; Freedman, W. L.; Gonzalez, C.; Goobar, A.; Holmbo, S.; Howell, D. A.; Johansson, J.; Kasliwal, M. M.; Kirshner, R. P.; Krisciunas, K.; Kulkarni, S. R.; Maguire, K.; Milne, P. A.; Morrell, N.; Nugent, P. E.; Ofek, E. O.; Osip, D.; Palunas, P.; Perley, D. A.; Persson, S. E.; Piro, A. L.; Rabus, M.; Roth, M.; Schiefelbein, J. M.; Srivastav, S.; Sullivan, M.; Suntzeff, N. B.; Surace, J.; Wo?niak, P. R.; Yaron, O.

    2015-05-22

    We present near-infrared (NIR) time-series spectroscopy, as well as complementary ultraviolet (UV), optical, and NIR data, of the Type Ia supernova (SN Ia) iPTF13ebh, which was discovered within two days from the estimated time of explosion. The first NIR spectrum was taken merely 2.3 days after explosion and may be the earliest NIR spectrum yet obtained of a SN Ia. The most striking features in the spectrum are several NIR C I lines, and the C I?1.0693 ?m line is the strongest ever observed in a SN Ia. Interestingly, no strong optical C II counterparts were found, even though the optical spectroscopic time series began early and is densely cadenced. Except at the very early epochs, within a few days from the time of explosion, we show that the strong NIR C I compared to the weaker optical C II appears to be general in SNe Ia. iPTF13ebh is a fast decliner with ?m15(B) = 1.79 0.01, and its absolute magnitude obeys the linear part of the width-luminosity relation. It is therefore categorized as a transitional event, on the fast-declining end of normal SNe Ia as opposed to subluminous/91bg-like objects. iPTF13ebh shows NIR spectroscopic properties that are distinct from both the normal and subluminous/91bg-like classes, bridging the observed characteristics of the two classes. These NIR observations suggest that composition and density of the inner core are similar to that of 91bg-like events, and that it has a deep-reaching carbon burning layer that is not observed in more slowly declining SNe Ia. Furthermore, there is also a substantial difference between the explosion times inferred from the early-time light curve and the velocity evolution of the Si II ?0.6355 ?m line, implying a long dark phase of ~4 days.

  13. TYPE Ia SUPERNOVA COLORS AND EJECTA VELOCITIES: HIERARCHICAL BAYESIAN REGRESSION WITH NON-GAUSSIAN DISTRIBUTIONS

    SciTech Connect (OSTI)

    Mandel, Kaisey S.; Kirshner, Robert P. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Foley, Ryan J., E-mail: kmandel@cfa.harvard.edu [Astronomy Department, University of Illinois at Urbana-Champaign, 1002 West Green Street, Urbana, IL 61801 (United States)

    2014-12-20

    We investigate the statistical dependence of the peak intrinsic colors of Type Ia supernovae (SNe Ia) on their expansion velocities at maximum light, measured from the Si II ?6355 spectral feature. We construct a new hierarchical Bayesian regression model, accounting for the random effects of intrinsic scatter, measurement error, and reddening by host galaxy dust, and implement a Gibbs sampler and deviance information criteria to estimate the correlation. The method is applied to the apparent colors from BVRI light curves and Si II velocity data for 79 nearby SNe Ia. The apparent color distributions of high-velocity (HV) and normal velocity (NV) supernovae exhibit significant discrepancies for B V and B R, but not other colors. Hence, they are likely due to intrinsic color differences originating in the B band, rather than dust reddening. The mean intrinsic B V and B R color differences between HV and NV groups are 0.06 0.02 and 0.09 0.02 mag, respectively. A linear model finds significant slopes of 0.021 0.006 and 0.030 0.009 mag (10{sup 3} km s{sup 1}){sup 1} for intrinsic B V and B R colors versus velocity, respectively. Because the ejecta velocity distribution is skewed toward high velocities, these effects imply non-Gaussian intrinsic color distributions with skewness up to +0.3. Accounting for the intrinsic-color-velocity correlation results in corrections to A{sub V} extinction estimates as large as 0.12 mag for HV SNe Ia and +0.06 mag for NV events. Velocity measurements from SN Ia spectra have the potential to diminish systematic errors from the confounding of intrinsic colors and dust reddening affecting supernova distances.

  14. DOE - Office of Legacy Management -- Madison - IL 26

    Office of Legacy Management (LM)

    Historical Operations: Conducted experimental work in natural uranium metal extrusion. ... 1992 IL.26-2 - DOE Memorandum; Wagoner to Price (OR); Authorization for Remedial Action at ...

  15. Local environment of Mn in Mn delta-doped Si layers

    SciTech Connect (OSTI)

    Xiao, Q.F.; Kahwaji, S.; Monchesky, T.L.; Gordon, R.A.; Crozier, E.D.

    2009-11-09

    Dilute magnetic semiconductors combine both magnetic ordering and semiconducting behaviour, leading to potential spintronic applications. Silicon containing dilute Mn impurities is a potential dilute magnetic semiconductor. We have grown Mn delta-doped films by deposition of 0.7 of a monolayer of Mn on Si(001) by molecular beam epitaxy and capping the film with Si. The magnetic properties are likely sensitive to the distribution of Mn on substitutional or interstitial sites and the formation of metallic precipitates. We have used polarization-dependent XAFS to examine the local structure. We compare to a thicker MnSi film grown on Si(111) and also examine the influence of lead on the manganese environment when used as a surfactant in the growth process.

  16. Structural, magnetic, and superconducting properties of pulsed-laser-deposition-grown La<mn>1.85mn> Sr<mn>0.15mn> CuO<mn>4mn> / La<mn>2mn>/>3mn> Ca<mn>1mn>/>3mn> MnO>3mn> superlattices on (001)-oriented LaSrAlO<mn>4mn> substrates

    SciTech Connect (OSTI)

    Das, S.; Sen, K.; Marozau, I.; Uribe-Laverde, M. A.; Biskup, N.; Varela, M.; Khaydukov, Y.; Soltwedel, O.; Keller, T.; Döbeli, M.; Schneider, C. W.; Bernhard, C.

    2014-03-12

    Epitaxial La<mn>1.85mn> Sr<mn>0.15mn> CuO<mn>4mn> / La<mn>2mn>/>3mn> Ca<mn>1mn>/>3mn> MnO>3mn> (LSCO/LCMO) superlattices (SL) on (001)- oriented LaSrAlO4 substrates have been grown with pulsed laser deposition (PLD) technique. Their structural, magnetic and superconducting properties have been determined with in-situ reflection high energy electron diffraction (RHEED), x-ray diffraction, specular neutron reflectometry, scanning transmission electron microscopy (STEM), electric transport, and magnetization measurements. We find that despite the large mismatch between the in-plane lattice parameters of LSCO (a = 0.3779 nm) and LCMO (a = 0.387 nm) these superlattices can be grown epitaxially and with a high crystalline quality. While the first LSCO layer remains clamped to the LSAO substrate, a sizeable strain relaxation occurs already in the first LCMO layer. The following LSCO and LCMO layers adopt a nearly balanced state in which the tensile and compressive strain effects yield alternating in-plane lattice parameters with an almost constant average value. No major defects are observed in the LSCO layers, while a significant number of vertical antiphase boundaries are found in the LCMO layers. The LSCO layers remain superconducting with a relatively high superconducting onset temperature of Tconset ≈ 36 K. The macroscopic superconducting response is also evident in the magnetization data due to a weak diamagnetic signal below 10 K for H ∥ ab and a sizeable paramagnetic shift for H ∥ c that can be explained in terms of a vortex-pinning-induced flux compression. The LCMO layers maintain a

  17. Type Ia supernova rate measurements to redshift 2.5 from CANDELS: Searching for prompt explosions in the early universe

    SciTech Connect (OSTI)

    Rodney, Steven A.; Riess, Adam G.; Graur, Or; Jones, David O. [Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, MD 21218 (United States); Strolger, Louis-Gregory; Dahlen, Tomas; Casertano, Stefano; Ferguson, Henry C.; Koekemoer, Anton M. [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Dickinson, Mark E. [National Optical Astronomy Observatory, 950 North Cherry Avenue, Tucson, AZ 85719 (United States); Garnavich, Peter [Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States); Hayden, Brian [E.O. Lawrence Berkeley National Lab, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Jha, Saurabh W.; McCully, Curtis; Patel, Brandon [Department of Physics and Astronomy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854 (United States); Kirshner, Robert P. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Mobasher, Bahram [Department of Physics and Astronomy, University of California, Riverside, CA 92521 (United States); Weiner, Benjamin J. [Department of Astronomy, University of Arizona, Tucson, AZ 85721 (United States); Cenko, S. Bradley [Astrophysics Science Division, NASA Goddard Space Flight Center, Mail Code 661, Greenbelt, MD 20771 (United States); Clubb, Kelsey I. [Department of Astronomy, University of California, Berkeley, CA 94720 (United States); and others

    2014-07-01

    The Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS) was a multi-cycle treasury program on the Hubble Space Telescope (HST) that surveyed a total area of ?0.25 deg{sup 2} with ?900 HST orbits spread across five fields over three years. Within these survey images we discovered 65 supernovae (SNe) of all types, out to z ? 2.5. We classify ?24 of these as Type Ia SNe (SNe Ia) based on host galaxy redshifts and SN photometry (supplemented by grism spectroscopy of six SNe). Here we present a measurement of the volumetric SN Ia rate as a function of redshift, reaching for the first time beyond z = 2 and putting new constraints on SN Ia progenitor models. Our highest redshift bin includes detections of SNe that exploded when the universe was only ?3 Gyr old and near the peak of the cosmic star formation history. This gives the CANDELS high redshift sample unique leverage for evaluating the fraction of SNe Ia that explode promptly after formation (<500 Myr). Combining the CANDELS rates with all available SN Ia rate measurements in the literature we find that this prompt SN Ia fraction is f{sub P} = 0.53{sub stat0.10}{sup 0.09}{sub sys0.26}{sup 0.10}, consistent with a delay time distribution that follows a simple t {sup 1} power law for all times t > 40 Myr. However, mild tension is apparent between ground-based low-z surveys and space-based high-z surveys. In both CANDELS and the sister HST program CLASH (Cluster Lensing And Supernova Survey with Hubble), we find a low rate of SNe Ia at z > 1. This could be a hint that prompt progenitors are in fact relatively rare, accounting for only 20% of all SN Ia explosionsthough further analysis and larger samples will be needed to examine that suggestion.

  18. Properties of (Ga,Mn)As codoped with Li

    SciTech Connect (OSTI)

    Miyakozawa, Shohei; Chen, Lin; Matsukura, Fumihiro; Ohno, Hideo

    2014-06-02

    We grow Li codoped (Ga,Mn)As layers with nominal Mn composition up to 0.15 by molecular beam epitaxy. The layers before and after annealing are characterized by x-ray diffraction, transport, magnetization, and ferromagnetic resonance measurements. The codoping with Li reduces the lattice constant and electrical resistivity of (Ga,Mn)As after annealing. We find that (Ga,Mn)As:Li takes similar Curie temperature to that of (Ga,Mn)As, but with pronounced magnetic moments and in-plane magnetic anisotropy, indicating that the Li codoping has nontrivial effects on the magnetic properties of (Ga,Mn)As.

  19. DOE - Office of Legacy Management -- American Machine and Metals Inc - IL

    Office of Legacy Management (LM)

    24 Metals Inc - IL 24 FUSRAP Considered Sites Site: American Machine and Metals Inc (IL.24 ) Eliminated from consideration under FUSRAP Designated Name: Not Designated Alternate Name: None Location: E. Moline , Illinois IL.24-1 Evaluation Year: 1994 IL.24-2 IL.24-3 Site Operations: Tested process for dewatering green salt by centrifugation. IL.24-1 IL.24-2 Site Disposition: Eliminated - Potential for contamination considered remote due to limited amount of radioactive materials handled

  20. DOE - Office of Legacy Management -- Lindsay Light and Chemical Co - IL 10

    Office of Legacy Management (LM)

    Lindsay Light and Chemical Co - IL 10 FUSRAP Considered Sites Site: LINDSAY LIGHT AND CHEMICAL CO. ( IL.10 ) Eliminated from consideration under FUSRAP Designated Name: Not Designated Alternate Name: None Location: West Chicago , Illinois IL.10-3 Evaluation Year: 1995 IL.10-4 Site Operations: Processed thorium ores - chiefly monazite sands - for thorium and rare earth metals. IL.10-1 IL.10-2 Site Disposition: Eliminated - No Authority - NRC licensed operation IL.10-4 Radioactive Materials

  1. Spin reorientation and Ce-Mn coupling in antiferromagnetic oxypnictide CeMnAsO

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

    Zhang, Qiang; Tian, Wei; Peterson, Spencer G.; Dennis, Kevin W.; Vaknin, David

    2015-02-18

    Structure and magnetic properties of high-quality polycrystlline CeMnAsO, a parent compound of the “1111”-type oxypnictides, have been investigated using neutron powder diffraction and magnetization measurements. We find that CeMnAsO undergoes a C-type antiferromagnetic order with Mn2+(S = 5/2) moments pointing along the c axis below a relatively high Néel temperature of TN = 347(1) K. Below TSR = 35 K, two simultaneous transitions occur where the Mn moments reorient from the c axis to the ab plane preserving the C-type magnetic order, and Ce moments undergo long-range AFM ordering with antiparallel moments pointing in the ab plane. Another transition tomore » a noncollinear magnetic structure occurs below 7 K. The ordered moments of Mn and Ce at 2 K are 3.32(4) μB and 0.81(4)μB, respectively. We find that CeMnAsO primarily falls into the category of a local-moment antiferromagnetic insulator in which the nearest-neighbor interaction (J1) is dominant with J2 < J1/2 in the context of J1 – J2 – Jc model. The spin reorientation transition driven by the coupling between Ce and the transition metal seems to be common to Mn, Fe, and Cr ions, but not to Co and Ni ions in the isostructural oxypnictides. As a result, a schematic illustration of magnetic structures in Mn and Ce sublattices in CeMnAsO is presented.« less

  2. SNe Ia tests of quintessence tracker cosmology in an anisotropic background

    SciTech Connect (OSTI)

    Miranda, W.; Carneiro, S.; Pigozzo, C. E-mail: saulo.carneiro@pq.cnpq.br

    2014-07-01

    We investigate the observational effects of a quintessence model in an anisotropic spacetime. The anisotropic metric is a non-rotating particular case of a generalized Gödel's metric and is classified as Bianchi III. This metric is an exact solution of the Einstein-Klein-Gordon field equations with an anisotropic scalar field ψ, which is responsible for the anisotropy of the spacetime geometry. We test the model against observations of type Ia supernovae, analyzing the SDSS dataset calibrated with the MLCS2k2 fitter, and the results are compared to standard quintessence models with Ratra-Peebles potentials. We obtain a good agreement with observations, with best values for the matter and curvature density parameters Ω{sub M} = 0.29 and Ω{sub k}= 0.01 respectively. We conclude that present SNe Ia observations cannot, alone, distinguish a possible anisotropic axis in the cosmos.

  3. DOE - Office of Legacy Management -- W E Pratt Manufacturing Co - IL 12

    Office of Legacy Management (LM)

    E Pratt Manufacturing Co - IL 12 FUSRAP Considered Sites Site: W.E. PRATT MANUFACTURING CO. (IL.12) Eliminated from consideration under FUSRAP Designated Name: Not Designated Alternate Name: William E. Pratt Manufacturing Co. Klassing Handbrake Company IL.12-1 IL.12-2 Location: 18 Henderson Street , Joliet , Illinois IL.12-3 Evaluation Year: 1990 IL.12-4 IL.12-5 Site Operations: Performed metal fabrication tasks (machining and grinding). IL.12-1 IL.12-4 Site Disposition: Eliminated - Radiation

  4. Magnetoelectric coupling tuned by competing anisotropies in Mn...

    Office of Scientific and Technical Information (OSTI)

    Magnetoelectric coupling tuned by competing anisotropies in Mn 1 - x Ni x TiO 3 Prev Next Title: Magnetoelectric coupling tuned by competing anisotropies in Mn 1 - x Ni x TiO ...

  5. THE EARLIEST NEAR-INFRARED TIME-SERIES SPECTROSCOPY OF A TYPE Ia SUPERNOVA

    SciTech Connect (OSTI)

    Hsiao, E. Y.; Phillips, M. M.; Morrell, N.; Contreras, C.; Roth, M.; Marion, G. H.; Kirshner, R. P.; Burns, C. R.; Freedman, W. L.; Persson, S. E.; Winge, C.; Gerardy, C. L.; Hoeflich, P.; Im, M.; Jeon, Y.; Pignata, G.; Stanishev, V.; and others

    2013-04-01

    We present ten medium-resolution, high signal-to-noise ratio near-infrared (NIR) spectra of SN 2011fe from SpeX on the NASA Infrared Telescope Facility (IRTF) and Gemini Near-Infrared Spectrograph (GNIRS) on Gemini North, obtained as part of the Carnegie Supernova Project. This data set constitutes the earliest time-series NIR spectroscopy of a Type Ia supernova (SN Ia), with the first spectrum obtained at 2.58 days past the explosion and covering -14.6 to +17.3 days relative to B-band maximum. C I {lambda}1.0693 {mu}m is detected in SN 2011fe with increasing strength up to maximum light. The delay in the onset of the NIR C I line demonstrates its potential to be an effective tracer of unprocessed material. For the first time in a SN Ia, the early rapid decline of the Mg II {lambda}1.0927 {mu}m velocity was observed, and the subsequent velocity is remarkably constant. The Mg II velocity during this constant phase locates the inner edge of carbon burning and probes the conditions under which the transition from deflagration to detonation occurs. We show that the Mg II velocity does not correlate with the optical light-curve decline rate {Delta}m{sub 15}(B). The prominent break at {approx}1.5 {mu}m is the main source of concern for NIR k-correction calculations. We demonstrate here that the feature has a uniform time evolution among SNe Ia, with the flux ratio across the break strongly correlated with {Delta}m{sub 15}(B). The predictability of the strength and the onset of this feature suggests that the associated k-correction uncertainties can be minimized with improved spectral templates.

  6. Comparing the host galaxies of type Ia, type II, and type Ibc supernovae

    SciTech Connect (OSTI)

    Shao, X.; Liang, Y. C.; Chen, X. Y.; Zhong, G. H.; Deng, L. C.; Zhang, B.; Shi, W. B.; Zhou, L.; Dennefeld, M.; Hammer, F.; Flores, H. E-mail: ycliang@bao.ac.cn

    2014-08-10

    We compare the host galaxies of 902 supernovae (SNe), including SNe Ia, SNe II, and SNe Ibc, which are selected by cross-matching the Asiago Supernova Catalog with the Sloan Digital Sky Survey (SDSS) Data Release 7. We selected an additional 213 galaxies by requiring the light fraction of spectral observations to be >15%, which could represent well the global properties of the galaxies. Among these 213 galaxies, 135 appear on the Baldwin-Phillips-Terlevich diagram, which allows us to compare the hosts in terms of whether they are star-forming (SF) galaxies, active galactic nuclei (AGNs; including composites, LINERs, and Seyfert 2s) or absorption-line galaxies (Absorps; i.e., their related emission lines are weak or non-existent). The diagrams related to the parameters D{sub n}(4000), H?{sub A}, stellar masses, star formation rates (SFRs), and specific SFRs for the SNe hosts show that almost all SNe II and most of the SNe Ibc occur in SF galaxies, which have a wide range of stellar masses and low D{sub n}(4000). The SNe Ia hosts as SF galaxies following similar trends. A significant fraction of SNe Ia occurs in AGNs and absorption-line galaxies, which are massive and have high D{sub n}(4000). The stellar population analysis from spectral synthesis fitting shows that the hosts of SNe II have a younger stellar population than hosts of SNe Ia. These results are compared with those of the 689 comparison galaxies where the SDSS fiber captures less than 15% of the total light. These comparison galaxies appear biased toward higher 12+log(O/H) (?0.1 dex) at a given stellar mass. Therefore, we believe the aperture effect should be kept in mind when the properties of the hosts for different types of SNe are discussed.

  7. Optical and ultraviolet observations of the narrow-lined type Ia SN 2012fr in NGC 1365

    SciTech Connect (OSTI)

    Zhang, Ju-Jia; Bai, Jin-Ming; Wang, Bo; Liu, Zheng-Wei [Yunnan Observatories (YNAO), Chinese Academy of Sciences, Kunming 650011 (China); Wang, Xiao-Feng; Zhao, Xu-Lin; Chen, Jun-Cheng [Physics Department and Tsinghua Center for Astrophysics (THCA), Tsinghua University, Beijing 100084 (China); Zhang, Tian-Meng, E-mail: jujia@ynao.ac.cn, E-mail: baijinming@ynao.ac.cn, E-mail: wang_xf@mail.tsinghua.edu.cn [National Astronomical Observatories of China (NAOC), Chinese Academy of Sciences, Beijing 100012 (China)

    2014-07-01

    Extensive optical and ultraviolet (UV) observations of the type Ia supernova (SN Ia) 2012fr are presented in this paper. It has a relatively high luminosity, with an absolute B-band peak magnitude of about 19.5 mag and a smaller post-maximum decline rate than normal SNe Ia (e.g., ?m {sub 15}(B) =0.85 0.05 mag). Based on the UV and optical light curves, we derived that a {sup 56}Ni mass of about 0.88 M {sub ?} was synthesized in the explosion. The earlier spectra are characterized by noticeable high-velocity features of Si II ?6355 and Ca II with velocities in the range of ?22, 000-25, 000 km s{sup 1}. At around the maximum light, these spectral features are dominated by the photospheric components which are noticeably narrower than normal SNe Ia. The post-maximum velocity of the photosphere remains almost constant at ?12,000 km s{sup 1} for about one month, reminiscent of the behavior of some luminous SNe Ia like SN 1991T. We propose that SN 2012fr may represent a subset of the SN 1991T-like SNe Ia viewed in a direction with a clumpy or shell-like structure of ejecta, in terms of a significant level of polarization reported in Maund et al. in 2013.

  8. Influence of interstitial Mn on magnetism in room-temperature ferromagnet Mn(1+delta)Sb

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

    Taylor, Alice E; Berlijn, Tom; Hahn, Steven E; May, Andrew F; Williams, Travis J; Poudel, Lekhanath N; Calder, Stuart A; Fishman, Randy Scott; Stone, Matthew B; Aczel, Adam A; et al

    2015-01-01

    We report elastic and inelastic neutron scattering measurements of the high-TC ferromagnet Mn(1+delta)Sb. Measurements were performed on a large, TC = 434 K, single crystal with interstitial Mn content of delta=0.13. The neutron diffraction results reveal that the interstitial Mn has a magnetic moment, and that it is aligned antiparallel to the main Mn moment. We perform density functional theory calculations including the interstitial Mn, and find the interstitial to be magnetic in agreement with the diffraction data. The inelastic neutron scattering measurements reveal two features in the magnetic dynamics: i) a spin-wave-like dispersion emanating from ferromagnetic Bragg positions (Hmore » K 2n), and ii) a broad, non-dispersive signal centered at forbidden Bragg positions (H K 2n+1). The inelastic spectrum cannot be modeled by simple linear spin-wave theory calculations, and appears to be significantly altered by the presence of the interstitial Mn ions. The results show that the influence of the int« less

  9. Influence of interstitial Mn on magnetism in room-temperature ferromagnet Mn(1+delta)Sb

    SciTech Connect (OSTI)

    Taylor, Alice E; Berlijn, Tom; Hahn, Steven E; May, Andrew F; Williams, Travis J; Poudel, Lekhanath N; Calder, Stuart A; Fishman, Randy Scott; Stone, Matthew B; Aczel, Adam A; Cao, Huibo; Lumsden, Mark D; Christianson, Andrew D

    2015-01-01

    We report elastic and inelastic neutron scattering measurements of the high-TC ferromagnet Mn(1+delta)Sb. Measurements were performed on a large, TC = 434 K, single crystal with interstitial Mn content of delta=0.13. The neutron diffraction results reveal that the interstitial Mn has a magnetic moment, and that it is aligned antiparallel to the main Mn moment. We perform density functional theory calculations including the interstitial Mn, and find the interstitial to be magnetic in agreement with the diffraction data. The inelastic neutron scattering measurements reveal two features in the magnetic dynamics: i) a spin-wave-like dispersion emanating from ferromagnetic Bragg positions (H K 2n), and ii) a broad, non-dispersive signal centered at forbidden Bragg positions (H K 2n+1). The inelastic spectrum cannot be modeled by simple linear spin-wave theory calculations, and appears to be significantly altered by the presence of the interstitial Mn ions. The results show that the influence of the int

  10. CaMn2Al10: Itinerant Mn magnetism on the verge of magnetic order

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

    Steinke, L.; Simonson, J. W.; Yin, W. -G.; Smith, G. J.; Kistner-Morris, J. J.; Zellman, S.; Puri, A.; Aronson, M. C.

    2015-07-24

    We report the discovery of CaMn2Al10, a metal with strong magnetic anisotropy and moderate electronic correlations. Magnetization measurements find a Curie-Weiss moment of 0.83μB/Mn, significantly reduced from the Hund's rule value, and the magnetic entropy obtained from specific heat measurements is correspondingly small, only ≈ 9% of Rln2. These results imply that the Mn magnetism is highly itinerant, a conclusion supported by density functional theory calculations that find strong Mn-Al hybridization. Consistent with the layered nature of the crystal structure, the magnetic susceptibility χ is anisotropic below 20 K, with a maximum ratio of χ[010]/χ[001] ≈ 3.5. A strong power-lawmore » divergence χ(T) ~ T–1.2 below 20 K implies incipient ferromagnetic order, an Arrott plot analysis of the magnetization suggests a vanishing low Curie temperature TC ~ 0. Our experiments indicate that CaMn2Al10 is a rare example of a system where the weak and itinerant Mn-based magnetism is poised on the verge of order.« less

  11. Intrathymic radioresistant stem cells follow an IL-2/IL-2R pathway during thymic regeneration after sublethal irradiation

    SciTech Connect (OSTI)

    Zuniga-Pfluecker, J.C.K.; Kruisbeek, A.M. )

    1990-05-15

    Sublethally irradiated mice undergo thymic regeneration which follows a phenotypic pattern of events similar to that observed during normal fetal development. Thymic regeneration after irradiation is the product of a limited pool of intrathymic radioresistant stem cells undergoing simultaneous differentiation. We show that in this model of T cell development, thymic regeneration follows a pathway in which the IL-2R is transiently expressed on CD4-/CD8- cells. IL-2R expression occurred during the exponential growth period of thymic regeneration, and IL-2R blocking prevented this explosive growth. Flow cytometry analysis revealed that the IL-2R blockade affected primarily the development of the immature CD3-/CD4-/CD8- (triple negative) cells and their ability to generate CD3+/CD4+/CD8+ or CD3+/CD4+/CD8- and CD3+/CD4-/CD8+ thymocytes. Thus, our findings demonstrate that blocking of the IL-2R resulted in an arrest in proliferation and differentiation by intrathymic radioresistant stem cells, indicating that the IL-2/IL-2R pathway is necessary for the expansion of immature triple negative T cells.

  12. Effect of Mn doping on structural and magnetic susceptibility of C-type rare earth nano oxides Er{sub 2?x}Mn{sub x}O{sub 3}

    SciTech Connect (OSTI)

    Heiba, Zein K.; Taif University, Faculty of Science, Physics Department ; Mohamed, Mohamed Bakr; Fuess, H.

    2012-12-15

    Graphical abstract: Display Omitted Highlights: ? Er{sub 2?x}Mn{sub x}O{sub 3} (0.0 ? x ? 0.20) prepared by solgel method. ? The change in lattice parameter is not linear with x due to the change in crystallite size with doping. ? Anomalous concentration dependence is found in magnetic susceptibility. ? The effective magnetic moment ?{sub eff} is found to decrease with composition parameter x. ? Superexchange interactions between Er ions depending on the amount of Mn or Er in different sites. -- Abstract: The manganese doped rare earth oxides Er{sub 2?x}Mn{sub x} O{sub 3} (0.0 ? x ? 0.20) were synthesized by a solgel process and analyzed by X-ray diffraction using Rietveld refinement methods. A single phase solid solution is formed up to x = 0.15 while for x ? 0.2 a manganese oxide phase appears in the diffraction pattern. Preferential cationic distribution between the non-equivalent sites 8b and 24d of space group Ia3{sup } is found for all samples but to a different extent. The octahedral volume and average bond length of Er{sub 1}-O for 8b site decrease while both octahedral volume and bond length of Er{sub 2}-O for 24d site increase. Magnetization measurements were done in the temperature range 5300 K. The effective magnetic moment ?{sub eff} is found to decrease with composition parameter x, except for sample x = 0.05 where the magnetization is enhanced. The Curie-Weiss paramagnetic temperatures indicate antiferromagnetic interaction.

  13. Opti-MN Impact House Presentation | Department of Energy

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

    Opti-MN Impact House Presentation Opti-MN Impact House Presentation Opti-MN was the Grand Winner of the 2015 Race to Zero Student Design Competition. View the presentation for the Opti-MN Impact House below. Read a full list of the winning teams. Opti-MN Presentation (5.74 MB) More Documents & Publications 2015 Race to Zero Competition Grand Winner and Grand Winner Finalist Team Submissions 2016 Race to Zero Competition Winner Team Presentations 2014 Race to Zero Student Design Competition:

  14. DOE - Office of Legacy Management -- Great Lakes Carbon Corp - IL 21

    Office of Legacy Management (LM)

    Great Lakes Carbon Corp - IL 21 FUSRAP Considered Sites Site: GREAT LAKES CARBON CORP. ( IL.21 ) Eliminated from further consideration under FUSRAP Designated Name: Not Designated Alternate Name: None Location: 333 North Michigan Avenue , Chicago , Illinois IL.21-1 Evaluation Year: 1987 IL.21-1 Site Operations: Facility performed a limited amount of nuclear fuel fabrication in the 1950s. Facility also developed graphite production under an AEC contract. IL.21-1 IL.21-3 Site Disposition:

  15. DOE - Office of Legacy Management -- Chicago South IL Site -...

    Office of Legacy Management (LM)

    This site is managed by the U.S. Department of Energy Office of Legacy Management. IL.06-1 - DOE Memorandum; Coffman to LaGrone; Subject: Designation of the University of Chicago ...

  16. 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.

  17. Solid Solution Phases in the Olivine-Type LiMnPO4/MnPO4 System

    SciTech Connect (OSTI)

    Chen, Guoying; Richardson, Thomas J.

    2009-04-07

    Nonstoichiometry is reported in the LiMnPO{sub 4}/MnPO{sub 4} system for the first time. As lithium is removed from crystalline LiMnPO{sub 4} by chemical or electrochemical methods, the resulting two phase mixture consists of stoichiometric LiMnPO{sub 4} and a delithiated phase, Li{sub y}MnPO{sub 4}, whose lattice parameters depend upon the global extent of delithiation and on the crystalline domain size of the delithiated phase. This behavior is reproduced during electrochemical insertion of lithium. Again, no evidence for nonstoichiometry was found in the vicinity of LiMnPO{sub 4}. Attempts to create single phase solid solutions by heating mixtures of the two phases failed due to the thermal instability of Li{sub y}MnPO{sub 4}.

  18. Origin State>> CA ID ID IL IL KY NM NM NV NY OH TN TN TN, WA,

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

    IL IL KY NM NM NV NY OH TN TN TN, WA, CA TN TN TN TN Total Shipments by Route Lawrence Livermore National Laboratory Batelle Energy Alliance Idaho National Laboratory Energx Argonne National Laboratory Argonne National Laboratory Paducah Gaseous Diffusion Plant Sandia National Laboratory Los Alamos National Laboratory National Security Technologies West Valley Environmental Services Portsmouth Gaseous Diffusion Plant Duratek/Energy Solutions Babcox & Wilcox Technical Services Y-12 Plant

  19. Interleukin-2 (IL-2) dependent expression of biologically relevant IL-2 receptors: uncoupling of anti-T3 induced receptor expression with cyclosporin

    SciTech Connect (OSTI)

    Gitter, A.B.D.; Labus, J.M.; Butler, L.D.

    1986-03-01

    Human peripheral blood T cell expression of IL-2 receptors (IL-2R), detected by both immunocytofluorometry and /sup 125/I-IL-2 binding, was studied using lymphocytes stimulated with monoclonal anti-T3 antibodies (Leu-4, OKT3). Lymphocytes, isolated from healthy individuals, were prescreened and classified as Leu-4 responders or non-responders according to 72 h /sup 3/H-thymidine incorporation experiments. Leu-4 non-responder lymphocytes, though capable of normal IL-2R expression and IL-2 secretion when cultured with OKT3 (IgG2a), expressed little to no IL-2R nor secreted IL-2 when stimulated with Leu-4 (IgG1). In addition, the amount of IL-2 secreted by Leu-4 stimulated, Leu-4 responder cells, was one-third- to one-fifth of that detected when OKT3 was used as the stimulant. The addition of recombinant IL-2 (rIL-2) to a Leu-4 stimulated, Leu-4 non-responder lymphocyte culture, resulted in the expression of IL-2R and cellular proliferation, indicating that IL-2 upregulated its biologically relevant receptor. As expected, cyclosporin-A (CSA) inhibited the secretion of IL-2 and subsequent proliferation of Leu-4 stimulated, Leu-4 responder cells. Unexpectedly, however, the expression of IL-2R was also blocked. Exogenous rIL-2 partially reversed the effect of CSA on IL-2R expression and proliferation. The results indicate that IL-2 may provide an additional, required signal for optimal IL-2R expression.

  20. A SUPER-EDDINGTON WIND SCENARIO FOR THE PROGENITORS OF TYPE Ia SUPERNOVAE

    SciTech Connect (OSTI)

    Ma, Xin; Chen, Xuefei; Chen, Hai-liang; Han, Zhanwen; Denissenkov, Pavel A. E-mail: cxf@ynao.ac.cn

    2013-12-01

    The accretion of hydrogen-rich material on to carbon-oxygen white dwarfs (CO WDs) is crucial for understanding Type Ia supernova (SN Ia) from the single-degenerate model, but this process has not been well understood due to the numerical difficulties in treating H and He flashes during the accretion. For CO WD masses from 0.5 to 1.378 M {sub ?} and accretion rates in the range from 10{sup 8} to 10{sup 5} M {sub ?} yr{sup 1}, we simulated the accretion of solar-composition material on to CO WDs using the state-of-the-art stellar evolution code of MESA. For comparison with steady-state models, we first ignored the contribution from nuclear burning to the luminosity when determining the Eddington accretion rate, and found that the properties of H burning in our accreting CO WD models are similar to those from the steady-state models, except that the critical accretion rates at which the WDs turn into red giants or H-shell flashes occur on their surfaces are slightly higher than those from the steady-state models. However, the super-Eddington wind is triggered at much lower accretion rates than previously thought, when the contribution of nuclear burning to the total luminosity is included. This super-Eddington wind naturally prevents the CO WDs with high accretion rates from becoming red giants, thus presenting an alternative to the optically thick wind proposed by Hachisu etal. Furthermore, the super-Eddington wind works in low-metallicity environments, which may explain SNe Ia observed at high redshifts.

  1. SPECTROPOLARIMETRY OF THE TYPE Ia SN 2007sr TWO MONTHS AFTER MAXIMUM LIGHT

    SciTech Connect (OSTI)

    Zelaya, P.; Quinn, J. R.; Clocchiatti, A.; Baade, D.; Patat, F.; Hoeflich, P.; Maund, J.; Wang, L.; Wheeler, J. C.

    2013-02-01

    We present late-time spectropolarimetric observations of SN 2007sr, obtained with the Very Large Telescope at the ESO Paranal Observatory when the object was 63 days after maximum light. The late-time spectrum displays strong line polarization in the Ca II absorption features. SN 2007sr adds to the case of some normal Type Ia supernovae that show high line polarization or repolarization at late times, a fact that might be connected with the presence of high-velocity features at early times.

  2. Spectroscopic Determination of the Low Redshift Type Ia Supernova Rate from the Sloan Digital Sky Survey

    SciTech Connect (OSTI)

    Krughoff, K. S.; Connolly, Andrew J.; Frieman, Joshua; SubbaRao, Mark; Kilper, Gary; Schneider, Donald P.

    2011-04-10

    Supernova rates are directly coupled to high mass stellar birth and evolution. As such, they are one of the few direct measures of the history of cosmic stellar evolution. In this paper we describe an probabilistic technique for identifying supernovae within spectroscopic samples of galaxies. We present a study of 52 type Ia supernovae ranging in age from -14 days to +40 days extracted from a parent sample of \\simeq 50,000 spectra from the SDSS DR5. We find a Supernova Rate (SNR) of 0.472^{+0.048}_{-0.039}(Systematic)^{+0.081}_{-0.071}(Statistical)SNu at a redshift of = 0.1. This value is higher than other values at low redshift at the 1{\\sigma}, but is consistent at the 3{\\sigma} level. The 52 supernova candidates used in this study comprise the third largest sample of supernovae used in a type Ia rate determination to date. In this paper we demonstrate the potential for the described approach for detecting supernovae in future spectroscopic surveys.

  3. TYCHO SN 1572: A NAKED Ia SUPERNOVA REMNANT WITHOUT AN ASSOCIATED AMBIENT MOLECULAR CLOUD

    SciTech Connect (OSTI)

    Tian, W. W.; Leahy, D. A.

    2011-03-10

    The historical supernova remnant (SNR) Tycho SN 1572 originates from the explosion of a normal Type Ia supernova that is believed to have originated from a carbon-oxygen white dwarf in a binary system. We analyze the 21 cm continuum, H I, and {sup 12}CO-line data from the Canadian Galactic Plane Survey in the direction of SN 1572 and the surrounding region. We construct H I absorption spectra to SN 1572 and three nearby compact sources. We conclude that SN 1572 has no molecular cloud interaction, which argues against previous claims that a molecular cloud is interacting with the SNR. This new result does not support a recent claim that dust, newly detected by AKARI, originates from such an SNR-cloud interaction. We suggest that the SNR has a kinematic distance of 2.5-3.0 kpc based on a nonlinear rotational curve model. Very high energy {gamma}-ray emission from the remnant has been detected by the VERITAS telescope, so our result shows that its origin should not be an SNR-cloud interaction. Both radio and X-ray observations support that SN 1572 is an isolated Type Ia SNR.

  4. Spectroscopic Observations and Analysis of the Unusual Type Ia SN1999ac

    SciTech Connect (OSTI)

    Garavini, G.; Aldering, G.; Amadon, A.; Amanullah, R.; Astier,P.; Balland, C.; Blanc, G.; Conley, A.; Dahlen, T.; Deustua, S.E.; Ellis,R.; Fabbro, S.; Fadeyev, V.; Fan, X.; Folatelli, G.; Frye, B.; Gates,E.L.; Gibbons, R.; Goldhaber, G.; Goldman, B.; Goobar, A.; Groom, D.E.; Haissinski, J.; Hardin, D.; Hook, I.; Howell, D.A.; Kent, S.; Kim, A.G.; Knop, R.A.; Kowalski, M.; Kuznetsova, N.; Lee, B.C.; Lidman, C.; Mendez,J.; Miller, G.J.; Moniez, M.; Mouchet, M.; Mourao, A.; Newberg, H.; Nobili, S.; Nugent, P.E.; Pain, R.; Perdereau, O.; Perlmutter, S.; Quimby, R.; Regnault, N.; Rich, J.; Richards, G.T.; Ruiz-Lapuente, P.; Schaefer, B.E.; Schahmaneche, K.; Smith, E.; Spadafora, A.L.; Stanishev,V.; Thomas, R.C.; Walton, N.A.; Wang, L.; Wood-Vasey, W.M.

    2005-07-12

    The authors present optical spectra of the peculiar Type Ia supernova (SN Ia) 1999ac. The data extend from -15 to +42 days with respect to B-band maximum and reveal an event that is unusual in several respects. prior to B-band maximum, the spectra resemble those of SN 1999aa, a slowly declining event, but possess stronger Si II and Ca II signatures (more characteristic of a spectroscopically normal SN). Spectra after B-band maximum appear more normal. The expansion velocities inferred from the Iron lines appear to be lower than average; whereas, the expansion velocity inferred from Calcium H and K are higher than average. The expansion velocities inferred from the Iron lines appear to be lower than average; whereas, the expansion velocity inferred from Calcium H and K are higher than average. The expansion velocities inferred from Si II are among the slowest ever observed, though SN 1999ac is not particularly dim. The analysis of the parameters v{sub 10}(Si II), R(Si II), v, and {Delta}m{sub 15} further underlines the unique characteristics of SN 1999ac. They find convincing evidence of C II {lambda}6580 in the day -15 spectrum with ejection velocity v > 16,000 km s{sup -1}, but this signature disappears by day -9. This rapid evolution at early times highlights the importance of extremely early-time spectroscopy.

  5. Consistent use of type Ia supernovae highly magnified by galaxy clusters to constrain the cosmological parameters

    SciTech Connect (OSTI)

    Zitrin, Adi [Cahill Center for Astronomy and Astrophysics, California Institute of Technology, MS 249-17, Pasadena, CA 91125 (United States); Redlich, Matthias [Universitt Heidelberg, Zentrum fr Astronomie, Institut fr Theoretische Astrophysik, Philosophenweg 12, D-69120 Heidelberg (Germany); Broadhurst, Tom, E-mail: adizitrin@gmail.com [Department of Theoretical Physics, University of Basque Country UPV/EHU, Bilbao (Spain)

    2014-07-01

    We discuss how Type Ia supernovae (SNe) strongly magnified by foreground galaxy clusters should be self-consistently treated when used in samples fitted for the cosmological parameters. While the cluster lens magnification of a SN can be well constrained from sets of multiple images of various background galaxies with measured redshifts, its value is typically dependent on the fiducial set of cosmological parameters used to construct the mass model. In such cases, one should not naively demagnify the observed SN luminosity by the model magnification into the expected Hubble diagram, which would create a bias, but instead take into account the cosmological parameters a priori chosen to construct the mass model. We quantify the effect and find that a systematic error of typically a few percent, up to a few dozen percent per magnified SN may be propagated onto a cosmological parameter fit unless the cosmology assumed for the mass model is taken into account (the bias can be even larger if the SN is lying very near the critical curves). We also simulate how such a bias propagates onto the cosmological parameter fit using the Union2.1 sample supplemented with strongly magnified SNe. The resulting bias on the deduced cosmological parameters is generally at the few percent level, if only few biased SNe are included, and increases with the number of lensed SNe and their redshift. Samples containing magnified Type Ia SNe, e.g., from ongoing cluster surveys, should readily account for this possible bias.

  6. DOE - Office of Legacy Management -- Quality Hardware and Machine Co - IL

    Office of Legacy Management (LM)

    11 Quality Hardware and Machine Co - IL 11 FUSRAP Considered Sites Site: QUALITY HARDWARE AND MACHINE CO. (IL.11) Eliminated from consideration under FUSRAP Designated Name: Not Designated Alternate Name: Ravenswood Venture Marden Manufacturing Co. IL.11-1 IL.11-2 Location: 5823/5849 North Ravenswood Avenue , Chicago , Illinois IL.11-3 Evaluation Year: 1990 IL.11-4 IL.11-5 Site Operations: From 1944 to 1945, entered into subcontracts with the University of Chicago to furnish personnel,

  7. Toward Exascale Computing of Type Ia and Ib,c Supernovae: V&V of Current

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

    Models | Argonne Leadership Computing Facility Toward Exascale Computing of Type Ia and Ib,c Supernovae: V&V of Current Models PI Name: Don Lamb PI Email: lamb@oddjob.uchicago.edu Institution: University Of Chicago Allocation Program: INCITE Allocation Hours at ALCF: 40,000,000 Year: 2012 Research Domain: Physics This project continues a program of verification and validation of Type Ia supernova models. More 3-D simulations of the explosion phase will be performed, along with 2-D

  8. Investigations of element spatial correlation in Mn-promoted...

    Office of Scientific and Technical Information (OSTI)

    Investigations of element spatial correlation in Mn-promoted Co-based Fischer-Tropsch synthesis catalysts This content will become publicly available on June 4, 2017 Title: ...

  9. DOE - Office of Legacy Management -- C-B Tool Products Co - IL 31

    Office of Legacy Management (LM)

    C-B Tool Products Co - IL 31 FUSRAP Considered Sites Site: C-B Tool Products Co. (IL.31 ) Eliminated from consideration under FUSRAP Designated Name: Not Designated Alternate Name: None Location: 956 East 58th Street , Chicago , Illinois IL.31-1 Evaluation Year: 1990 IL.31-2 Site Operations: Provided personnel, facilities, and equipment to produce special machining of parts for special equipment from materials furnished by the University. IL.31-4 Site Disposition: Eliminated - Potential for

  10. DOE - Office of Legacy Management -- Era Tool and Engineering Co - IL 29

    Office of Legacy Management (LM)

    Era Tool and Engineering Co - IL 29 FUSRAP Considered Sites Site: Era Tool and Engineering Co. (IL.29 ) Eliminated from consideration under FUSRAP Designated Name: Not Designated Alternate Name: Audi-Tex Industries, Incorporated IL.29-1 Location: 4555 West Addison Street , Chicago , Illinois IL.29-2 Evaluation Year: 1989 IL.29-3 Site Operations: From February 1944 through June 1944, provided personnel, facilities, and equipment to produce machined parts for special equipment, tools, jigs,

  11. DOE - Office of Legacy Management -- Max Zuckerman and Sons - IL 30

    Office of Legacy Management (LM)

    - IL 30 FUSRAP Considered Sites Site: MAX ZUCKERMAN & SONS (IL.30 ) Eliminated from consideration under FUSRAP Designated Name: Not Designated Alternate Name: None Location: 1925 N. Kenmore Avenue , Chicago , Illinois IL.30-1 Evaluation Year: 1994 IL.30-2 Site Operations: Sample sized quantities of radioactive materials were shipped through this location; broker arranged purchases of materials for third party buyers. IL.30-2 Site Disposition: Eliminated - Potential for contamination

  12. DOE - Office of Legacy Management -- Museum of Science and Industry - IL 03

    Office of Legacy Management (LM)

    Museum of Science and Industry - IL 03 FUSRAP Considered Sites Site: MUSEUM OF SCIENCE AND INDUSTRY ( IL.03 ) Eliminated from consideration under FUSRAP Designated Name: Not Designated Alternate Name: None Location: 57th Street and Lake Shore Drive , Chicago , Illinois IL.03-1 Evaluation Year: 1985 IL.03-2 IL.03-3 Site Operations: The Metallurgical Laboratory and Argonne National Laboratory occupied space in the Museum of Science and Industry from August 15, 1946 to July 15, 1953. Some handling

  13. Microsoft Word - MnO_Reduction bh

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

    May 2016 Figure 1. Schematic of flow-through system developed at SSRL. A reaction vessel with manganese oxides and media required for microbial experiments was kept anoxic with nitrogen gas and pH was measured using an environmental pH probe. A portion of the fluid was sampled using a peristaltic pump through anaerobic tubing to the beam line hutch where the x-ray beam sampled the Mn coordination environment, mineralogy, and redox state through a Kapton tape window on an x-ray flow-through cell.

  14. Spin caloritronics in graphene with Mn

    SciTech Connect (OSTI)

    Torres, Alberto Lima, Matheus P. Fazzio, A.; Silva, Antnio J. R. da

    2014-02-17

    We show that graphene with Mn adatoms trapped at single vacancies features spin-dependent Seebeck effect, thus enabling the use of this material for spin caloritronics. A gate potential can be used to tune its thermoelectric properties in a way it presents either a total spin polarized current, flowing in one given direction, or currents for both spins flowing in opposite directions without net charge transport. Moreover, we show that the thermal magnetoresistance can be tuned between ?100% and +100% by varying a gate potential.

  15. Acidic environment augments FcεRI-mediated production of IL-6 and IL-13 in mast cells

    SciTech Connect (OSTI)

    Kamide, Yosuke; Ishizuka, Tamotsu; Tobo, Masayuki; Tsurumaki, Hiroaki; Aoki, Haruka; Mogi, Chihiro; Nakakura, Takashi; Yatomi, Masakiyo; Ono, Akihiro; Koga, Yasuhiko; Sato, Koichi; Hisada, Takeshi; Dobashi, Kunio; Yamada, Masanobu; Okajima, Fumikazu

    2015-08-28

    Although blood pH is maintained in a narrow range of around pH 7.4 in living organisms, inflammatory loci are characterized by acidic conditions. Mast cells tend to reside close to the surface of the body in areas such as the mucosa and skin where they may be exposed to exogenous acids, and they play an important role in immune responses. However, little is known about the effects of extracellular acidification on the functions of mast cell. Here, we found that extracellular acidification increased the dinitrophenyl-conjugated human serum albumin (DNP-HSA)-induced production of interleukin (IL)-6 and IL-13 in MC/9 cells or bone marrow-derived mouse mast cells sensitized with anti-DNP IgE. Extracellular acidification also inhibited migration of MC/9 cells toward DNP-HSA. In addition, acidic pH stimulated antigen-induced activation of p38 mitogen-activated protein kinase (MAPK) and protein kinase B (Akt). These findings suggest that extracellular acidification augmented antigen/IgE-induced and FcεRI-mediated production of IL-6 and IL-13 in mast cells, and that this was associated with the enhancement of p38 MAPK and Akt activation. - Highlights: • Antigen-induced IL-6 and IL-13 production was augmented by acidic pH in mast cells. • Acidic pH-induced actions were associated with activation of p38 MAPK and Akt. • Inhibition of p38 MAPK and Akt attenuated cytokine responses to acidic pH. • Acidic pH effects are not attributable to actions of known proton-sensing GPCRs.

  16. Near-infrared line identification in type Ia supernovae during the transitional phase

    SciTech Connect (OSTI)

    Friesen, Brian; Baron, E.; Wisniewski, John P.; Miller, Timothy R.; Parrent, Jerod T.; Thomas, R. C.; Marion, G. H.

    2014-09-10

    We present near-infrared synthetic spectra of a delayed-detonation hydrodynamical model and compare them to observed spectra of four normal Type Ia supernovae ranging from day +56.5 to day +85. This is the epoch during which supernovae are believed to be undergoing the transition from the photospheric phase, where spectra are characterized by line scattering above an optically thick photosphere, to the nebular phase, where spectra consist of optically thin emission from forbidden lines. We find that most spectral features in the near-infrared can be accounted for by permitted lines of Fe II and Co II. In addition, we find that [Ni II] fits the emission feature near 1.98 μm, suggesting that a substantial mass of {sup 58}Ni exists near the center of the ejecta in these objects, arising from nuclear burning at high density.

  17. LAX XXlCfl jX?iK, Idd+?KYLViG?IA

    Office of Legacy Management (LM)

    f , : I~&l, samtier cipwati8Aa CffUm - . Jiux.lCJ d,# 1754 - - _- - .- t :; . Jesse e. ahizmn*~*ter -2.' -------- - _ &tV' hi@A l f izau Bkteriala ;' . . 1 -7 I _' i' . Fpr&G& r&Q Q,&& fu &fI& L;&& -l&d 2;,i' iI,;/Qi' rIGN CQ&GgJy p;E& p;~p>gyf LAX XXlCfl jX?iK, Idd+?KYLViG?IA i-icfer~~o is &o ta yaw rwarandu3;: l P iimwmbec L?, 1953, reque&in~ a d&q.&ti of khority tA A&sister prog= for th+zz developmrrrl,

  18. EARLY OBSERVATIONS AND ANALYSIS OF THE TYPE Ia SN 2014J IN M82

    SciTech Connect (OSTI)

    Marion, G. H.; Vinkó, J.; Sand, D. J.; Hsiao, E. Y.; Banerjee, D. P. K.; Joshi, V.; Venkataraman, V.; Ashok, N. M.; Valenti, S.; Howell, D. A.; Stritzinger, M. D.; Amanullah, R.; Johansson, J.; Binzel, R. P.; Bochanski, J. J.; Bryngelson, G. L.; Burns, C. R.; Drozdov, D.; Fieber-Beyer, S. K.; Graham, M. L.; and others

    2015-01-01

    We present optical and near infrared (NIR) observations of the nearby Type Ia SN 2014J. Seventeen optical and 23 NIR spectra were obtained from 10 days before (–10d) to 10 days after (+10d) the time of maximum B-band brightness. The relative strengths of absorption features and their patterns of development can be compared at one day intervals throughout most of this period. Carbon is not detected in the optical spectra, but we identify C I λ1.0693 in the NIR spectra. Mg II lines with high oscillator strengths have higher initial velocities than other Mg II lines. We show that the velocity differences can be explained by differences in optical depths due to oscillator strengths. The spectra of SN 2014J show that it is a normal SN Ia, but many parameters are near the boundaries between normal and high-velocity subclasses. The velocities for O I, Mg II, Si II, S II, Ca II, and Fe II suggest that SN 2014J has a layered structure with little or no mixing. That result is consistent with the delayed detonation explosion models. We also report photometric observations, obtained from –10d to +29d, in the UBVRIJH and K{sub s} bands. The template fitting package SNooPy is used to interpret the light curves and to derive photometric parameters. Using R{sub V} = 1.46, which is consistent with previous studies, SNooPy finds that A{sub V} = 1.80 for E(B – V){sub host} = 1.23 ± 0.06 mag. The maximum B-band brightness of –19.19 ± 0.10 mag was reached on February 1.74 UT ± 0.13 days and the supernova has a decline parameter, Δm {sub 15}, of 1.12 ± 0.02 mag.

  19. Magnetic Moment Enhancement for Mn7 Cluster on Graphene

    SciTech Connect (OSTI)

    Liu, Xiaojie; Wang, Cai-Zhuang; Lin, Hai-Qing; Ho, Kai-Ming

    2014-08-21

    Mn7 cluster on graphene with different structural motifs and magnetic orders are investigated systematically by first-principles calculations. The calculations show that Mn7 on graphene prefers a two-layer motif and exhibits a ferrimagnetic coupling. The magnetic moment of the Mn7 cluster increases from 5.0 ?B at its free-standing state to about 6.0 ?B upon adsorption on graphene. Mn7 cluster also induces about 0.3 ?B of magnetic moment in the graphene layer, leading to an overall enhancement of 1.3 ?B magnetic moment for Mn7 on graphene. Detail electron transfer and bonding analysis have been carried out to investigate the origin of the magnetic enhancement.

  20. Measurements of the Rate of Type Ia Supernovae at Redshift z < ~0.3 from the SDSS-II Supernova Survey

    SciTech Connect (OSTI)

    Dilday, Benjamin; Smith, Mathew; Bassett, Bruce; Becker, Andrew; Bender, Ralf; Castander, Francisco; Cinabro, David; Filippenko, Alexei V.; Frieman, Joshua A.; Galbany, Lluis; Garnavich, Peter M.; /Notre Dame U. /Stockholm U., OKC /Stockholm U.

    2010-01-01

    We present a measurement of the volumetric Type Ia supernova (SN Ia) rate based on data from the Sloan Digital Sky Survey II (SDSS-II) Supernova Survey. The adopted sample of supernovae (SNe) includes 516 SNe Ia at redshift z {approx}< 0.3, of which 270 (52%) are spectroscopically identified as SNe Ia. The remaining 246 SNe Ia were identified through their light curves; 113 of these objects have spectroscopic redshifts from spectra of their host galaxy, and 133 have photometric redshifts estimated from the SN light curves. Based on consideration of 87 spectroscopically confirmed non-Ia SNe discovered by the SDSS-II SN Survey, we estimate that 2.04{sub -0.95}{sup +1.61}% of the photometric SNe Ia may be misidentified. The sample of SNe Ia used in this measurement represents an order of magnitude increase in the statistics for SN Ia rate measurements in the redshift range covered by the SDSS-II Supernova Survey. If we assume a SN Ia rate that is constant at low redshift (z < 0.15), then the SN observations can be used to infer a value of the SN rate of r{sub V} = (2.69{sub -0.30-0.01}{sup +0.34+0.21}) x 10{sup -5} SNe yr{sup -1} Mpc{sup -3} (H{sub 0}/(70 km s{sup -1} Mpc{sup -1})){sup 3} at a mean redshift of {approx} 0.12, based on 79 SNe Ia of which 72 are spectroscopically confirmed. However, the large sample of SNe Ia included in this study allows us to place constraints on the redshift dependence of the SN Ia rate based on the SDSS-II Supernova Survey data alone. Fitting a power-law model of the SN rate evolution, r{sub V} (z) = A{sub p} x ((1+z)/(1+z{sub 0})){sup {nu}}, over the redshift range 0.0 < z < 0.3 with z{sub 0} = 0.21, results in A{sub p} = (3.43{sub -0.15}{sup +0.15}) x 10{sup -5} SNe yr{sup -1} Mpc{sup -3} (H{sub 0}/(70 km s{sup -1} Mpc{sup -1})){sup 3} and {nu} = 2.04{sub -0.89}{sup +0.90}.

  1. shaleoil1.pdf

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

    ... USA CANADA SD ND MT Saskatchewan Manitoba Dunn Wa rd Dawson McL ea n McK en zie Morton ... SIGNIFICANT BAKKEN OIL FIELDS Bakken Shale Extent Canada MT ID IL IA WY NV NE SD MN ND WI ...

  2. EVOLUTION OF POST-IMPACT REMNANT HELIUM STARS IN TYPE Ia SUPERNOVA REMNANTS WITHIN THE SINGLE-DEGENERATE SCENARIO

    SciTech Connect (OSTI)

    Pan, Kuo-Chuan; Ricker, Paul M.; Taam, Ronald E. E-mail: pmricker@illinois.edu

    2013-08-10

    The progenitor systems of Type Ia supernovae (SNe Ia) are still under debate. Based on recent hydrodynamics simulations, non-degenerate companions in the single-degenerate scenario (SDS) should survive the supernova (SN) impact. One way to distinguish between the SDS and the double-degenerate scenario is to search for the post-impact remnant stars (PIRSs) in SN Ia remnants. Using a technique that combines multi-dimensional hydrodynamics simulations with one-dimensional stellar evolution simulations, we have examined the post-impact evolution of helium-rich binary companions in the SDS. It is found that these helium-rich PIRSs (He PIRSs) dramatically expand and evolve to a luminous phase (L {approx} 10{sup 4} L{sub Sun }) about 10 yr after an SN explosion. Subsequently, they contract and evolve to become hot blue-subdwarf-like (sdO-like) stars by releasing gravitational energy, persisting as sdO-like stars for several million years before evolving to the helium red-giant phase. We therefore predict that a luminous OB-like star should be detectable within {approx}30 yr after the SN explosion. Thereafter, it will shrink and become an sdO-like star in the central regions of SN Ia remnants within star-forming regions for SN Ia progenitors evolved via the helium-star channel in the SDS. These He PIRSs are predicted to be rapidly rotating (v{sub rot} {approx}> 50 km s{sup -1}) and to have high spatial velocities (v{sub linear} {approx}> 500 km s{sup -1}). Furthermore, if SN remnants have diffused away and are not recognizable at a later stage, He PIRSs could be an additional source of single sdO stars and/or hypervelocity stars.

  3. DOE - Office of Legacy Management -- Eimco Corp - IL 0-01

    Office of Legacy Management (LM)

    Eimco Corp - IL 0-01 FUSRAP Considered Sites Site: Eimco Corp. (IL.0-01 ) Eliminated from consideration under FUSRAP Designated Name: Not Designated Alternate Name: None Location: Palatine , Illinois IL.0-01-1 Evaluation Year: 1987 IL.0-01-1 Site Operations: Conducted laboratory leaf filtration tests IL.0-01-1 Site Disposition: Eliminated - Potential for contamination considered remote based on the limited scope of activities at the site IL.0-01-1 Radioactive Materials Handled: Yes Primary

  4. DOE - Office of Legacy Management -- Granite City Army Depot - IL 0-02

    Office of Legacy Management (LM)

    Granite City Army Depot - IL 0-02 FUSRAP Considered Sites Site: GRANITE CITY ARMY DEPOT ( IL.0-02 ) Eliminated from consideration under FUSRAP - Referred to DOD Designated Name: Not Designated Alternate Name: None Location: Granite City , Illinois IL.0-02-1 Evaluation Year: 1987 IL.0-02-1 Site Operations: Site was used for storage of GSA thorium residues until circa 1964. IL.0-02-1 Site Disposition: Eliminated - Referred to DOD IL.0-02-1 Radioactive Materials Handled: Yes Primary Radioactive

  5. DOE - Office of Legacy Management -- Midwest Manufacturing Co - IL 0-04

    Office of Legacy Management (LM)

    Midwest Manufacturing Co - IL 0-04 FUSRAP Considered Sites Site: MIDWEST MANUFACTURING CO (IL.0-04 ) Eliminated from consideration under FUSRAP Designated Name: Not Designated Alternate Name: None Location: Evaluation Year: 1987 IL.0-04-3 Site Operations: Research and development on deep drawing of sheet metal in the mid- 1940s. IL.0-04-3 Site Disposition: Site Disposition IL.0-04-1 IL.0-04-3 Radioactive Materials Handled: None Indicated Primary Radioactive Materials Handled: None Indicated

  6. DOE - Office of Legacy Management -- Sciaky Brothers Inc - IL 0-06

    Office of Legacy Management (LM)

    Sciaky Brothers Inc - IL 0-06 FUSRAP Considered Sites Site: SCIAKY BROTHERS, INC (IL.0-06 ) Eliminated from consideration under FUSRAP Designated Name: Not Designated Alternate Name: None Location: 4915 West 67th Street , Chicago , Illinois IL.0-06-1 Evaluation Year: 1987 IL.0-06-2 Site Operations: One time operation involving stitch welding of uranium in 1953. IL.0-06-1 IL.0-06-2 Site Disposition: Eliminated - Potential for contamination considered remote based on limited operations at the site

  7. Mn4+ emission in pyrochlore oxides

    SciTech Connect (OSTI)

    Du, Mao-Hua

    2015-01-01

    For the existing Mn4+ activated red phosphors have relatively low emission energies (or long emission wavelengths) and are therefore inefficient for general lighting. Density functional calculations are performed to study Mn4+ emission in rare-earth hafnate, zirconate, and stannate pyrochlore oxides (RE2Hf2O7, RE2Zr2O7, and RE2Sn2O7). We show how the different sizes of the RE3+ cation in these pyrochlores affect the local structure of the distorted MnO6 octahedron, the Mn–O hybridization, and the Mn4+ emission energy. The Mn4+ emission energies of many pyrochlores are found to be higher than those currently known for Mn4+ doped oxides and should be closer to that of Y2O3:Eu3+ (the current commercial red phosphor for fluorescent lighting). The O–Mn–O bond angle distortion in a MnO6 octahedron is shown to play an important role in weakening Mn–O hybridization and consequently increasing the Mn4+ emission energy. Our result shows that searching for materials that allow significant O–Mn–O bond angle distortion in a MnO6 octahedron is an effective approach to find new Mn4+ activated red phosphors with potential to replace the relatively expensive Y2O3:Eu3+ phosphor.

  8. Structural and magnetic properties of Sm{sub 2?x}Mn{sub x}O{sub 3} nanoparticles

    SciTech Connect (OSTI)

    Heiba, Zein K.; Mohamed, Mohamed Bakr; Fuess, H.

    2013-10-15

    Graphical abstract: - Highlights: C-type Sm{sub 2?x}Mn{sub x}O{sub 3} (0.0 ? x ?0.20) is prepared by solgel method. A maximum solubility of x = 0.15 is confirmed by X-ray diffraction, Raman and infrared techniques. Samples with x > 0.05 exhibit weak ferromagnetic properties; for x ? 0.05 antiferromagnetic behaviors is obtained. Correlation between magnetic behaviors and structural and microstructural parameters is discussed. - Abstract: Mixed oxide Sm{sub 2?x}Mn{sub x}O{sub 3} (SMO), x = 0.0, 0.05, 0.10, 0.15 and 0.20 were synthesized by a solgel process. A single phase solid solution is formed up to x = 0.15 which confirmed by using X-ray diffraction, Raman spectroscopy and infrared techniques. Crystal structure and microstructure analyses were performed by Rietveld refinement. Preferential cationic distribution, over the two crystallographic sites 8b and 24d of space group Ia3{sup }, is found for doped samples but with different extent. The r.m.s. microstrain ??{sub L}{sup 2}?{sup 1/2} depends on composition x in a systematic way emphasizing the preferential distribution. Magnetization measurements show that samples with x ? 0.05 have antiferromagnetic behavior, while samples with x > 0.05 exhibit a weak ferromagnetic behavior with magnetic phase transformation at 15 and 16 K for x = 0.1 and x = 0.15, respectively.

  9. Electrochemical behavior of β-MnO{sub 2} and MnOOH nanorods in different electrolytes

    SciTech Connect (OSTI)

    Chinnasamy, Revathi; Thangavelu, Rajendrakumar Ramasamy

    2015-06-24

    A manganese dioxide (β-MnO{sub 2}) and MnOOH nanoparticles has been synthesized by hydrothermal method. As prepared samples are analyzed by X-ray Diffraction (XRD) and Field Emission Scanning Electron Microscopy (FESEM). FESEM showed rod morphology within the diameter of 50–200 and length of few nanometers. These nanorods are immobilized on a Glassy Carbon Electrode (GCE) by drop cast method. The comparative electrochemical behavior of β-MnO{sub 2} and MnOOH rod modified GCE electrodes are analyzed by cyclic Voltammetry (CV) method in different electrolytes of 0.1M KCl, 0.1M Na{sub 2}SO{sub 4}, 0.1M NaOH, 0.1M PBS, 0.1M H{sub 2}SO{sub 4}. From the cyclic Voltammetry analysis found that in all the electrolytes both β-MnO{sub 2} and MnOOH modified GCE electrodes exhibit electrochemical behavior and KCl shows well redox properties as compared with others. There is also an observable difference in reduction potential value of both crystalline nanostructurers and concluded that β-MnO{sub 2} has high catalytic ability as compared with MnOOH rods.

  10. Inverse spin Hall effect in Pt/(Ga,Mn)As

    SciTech Connect (OSTI)

    Nakayama, H.; Chen, L.; Chang, H. W.; Ohno, H.; Matsukura, F.

    2015-06-01

    We investigate dc voltages under ferromagnetic resonance in a Pt/(Ga,Mn)As bilayer structure. A part of the observed dc voltage is shown to originate from the inverse spin Hall effect. The sign of the inverse spin Hall voltage is the same as that in Py/Pt bilayer structure, even though the stacking order of ferromagnetic and nonmagnetic layers is opposite to each other. The spin mixing conductance at the Pt/(Ga,Mn)As interface is determined to be of the order of 10{sup 19 }m{sup −2}, which is about ten times greater than that of (Ga,Mn)As/p-GaAs.

  11. DOE - Office of Legacy Management -- Twin Cities Ammunition - MN 0-01

    Office of Legacy Management (LM)

    Twin Cities Ammunition - MN 0-01 FUSRAP Considered Sites Site: TWIN CITIES AMMUNITION (MN.0-01) Eliminated from further consideration under FUSRAP - Referred to DOD Designated Name: Not Designated Alternate Name: None Location: New Brighton , Minnesota MN.0-01-1 Evaluation Year: 1987 MN.0-01-2 Site Operations: Site was formerly licensed under 10CFR 70 by the NRC. MN.0-01-1 MN.0-01-2 Site Disposition: Eliminated - No Authority - Referred to DOD MN.0-01-1 Radioactive Materials Handled: None

  12. A Measurement of the Rate of Type Ia Supernovae in Galaxy Clusters from the SDSS-II Supernova Survey

    SciTech Connect (OSTI)

    Dilday, Benjamin; Bassett, Bruce; Becker, Andrew; Bender, Ralf; Castander, Francisco; Cinabro, David; Frieman, Joshua A.; Galbany, Lluis; Garnavich, Peter; Goobar, Ariel; Hopp, Ulrich; /Munich, Tech. U. /Munich U. Observ. /Tokyo U.

    2010-03-01

    We present measurements of the Type Ia supernova (SN) rate in galaxy clusters based on data from the Sloan Digital Sky Survey-II (SDSS-II) Supernova Survey. The cluster SN Ia rate is determined from 9 SN events in a set of 71 C4 clusters at z {le} 0.17 and 27 SN events in 492 maxBCG clusters at 0.1 {le} z {le} 0.3. We find values for the cluster SN Ia rate of (0.37{sub -0.12-0.01}{sup +0.17+0.01}) SNur h{sup 2} and (0.55{sub -0.11-0.01}{sup +0.13+0.02}) SNur h{sup 2} (SNux = 10{sup -12}L{sub x{circle_dot}}{sup -1} yr{sup -1}) in C4 and maxBCG clusters, respectively, where the quoted errors are statistical and systematic, respectively. The SN rate for early-type galaxies is found to be (0.31{sub -0.12-0.01}{sup +0.18+0.01}) SNur h{sup 2} and (0.49{sub -0.11-0.01}{sup +0.15+0.02}) SNur h{sup 2} in C4 and maxBCG clusters, respectively. The SN rate for the brightest cluster galaxies (BCG) is found to be (2.04{sub -1.11-0.04}{sup +1.99+0.07}) SNur h{sup 2} and (0.36{sub -0.30-0.01}{sup +0.84+0.01}) SNur h{sup 2} in C4 and maxBCG clusters, respectively. The ratio of the SN Ia rate in cluster early-type galaxies to that of the SN Ia rate in field early-type galaxies is 1.94{sub -0.91-0.015}{sup +1.31+0.043} and 3.02{sub -1.03-0.048}{sup +1.31+0.062}, for C4 and maxBCG clusters, respectively. The SN rate in galaxy clusters as a function of redshift, which probes the late time SN Ia delay distribution, shows only weak dependence on redshift. Combining our current measurements with previous measurements, we fit the cluster SN Ia rate data to a linear function of redshift, and find r{sub L} = [(0.49{sub -0.14}{sup +0.15}) + (0.91{sub -0.81}{sup +0.85}) x z] SNuB h{sup 2}. A comparison of the radial distribution of SNe in cluster to field early-type galaxies shows possible evidence for an enhancement of the SN rate in the cores of cluster early-type galaxies. With an observation of at most 3 hostless, intra-cluster SNe Ia, we estimate the fraction of cluster SNe that are

  13. PRODUCTION OF THE p-PROCESS NUCLEI IN THE CARBON-DEFLAGRATION MODEL FOR TYPE Ia SUPERNOVAE

    SciTech Connect (OSTI)

    Kusakabe, Motohiko; Iwamoto, Nobuyuki; Nomoto, Ken'ichi E-mail: iwamoto.nobuyuki@jaea.go.jp

    2011-01-01

    We calculate the nucleosynthesis of proton-rich isotopes in the carbon-deflagration model for Type Ia supernovae (SNe Ia). The seed abundances are obtained by calculating the s-process nucleosynthesis that is expected to occur in the repeating helium shell flashes on the carbon-oxygen (CO) white dwarf (WD) during mass accretion from a binary companion. When the deflagration wave passes through the outer layer of the CO WD, p-nuclei are produced by photodisintegration reactions on s-nuclei in a region where the peak temperature ranges from 1.9 to 3.6 x 10{sup 9} K. We confirm the sensitivity of the p-process on the initial distribution of s-nuclei. We show that the initial C/O ratio in the WD does not affect much the yield of p-nuclei. On the other hand, the abundance of {sup 22}Ne left after s-processing has a large influence on the p-process via the {sup 22}Ne({alpha},n) reaction. We find that about 50% of p-nuclides are co-produced when normalized to their solar abundances in all adopted cases of seed distribution. Mo and Ru, which are largely underproduced in Type II supernovae (SNe II), are produced more than in SNe II although they are underproduced with respect to the yield levels of other p-nuclides. The ratios between p-nuclei and iron in the ejecta are larger than the solar ratios by a factor of 1.2. We also compare the yields of oxygen, iron, and p-nuclides in SNe Ia and SNe II and suggest that SNe Ia could make a larger contribution than SNe II to the solar system content of p-nuclei.

  14. The crossing statistic: dealing with unknown errors in the dispersion of Type Ia supernovae

    SciTech Connect (OSTI)

    Shafieloo, Arman; Clifton, Timothy; Ferreira, Pedro E-mail: tclifton@astro.ox.ac.uk

    2011-08-01

    We propose a new statistic that has been designed to be used in situations where the intrinsic dispersion of a data set is not well known: The Crossing Statistic. This statistic is in general less sensitive than χ{sup 2} to the intrinsic dispersion of the data, and hence allows us to make progress in distinguishing between different models using goodness of fit to the data even when the errors involved are poorly understood. The proposed statistic makes use of the shape and trends of a model's predictions in a quantifiable manner. It is applicable to a variety of circumstances, although we consider it to be especially well suited to the task of distinguishing between different cosmological models using type Ia supernovae. We show that this statistic can easily distinguish between different models in cases where the χ{sup 2} statistic fails. We also show that the last mode of the Crossing Statistic is identical to χ{sup 2}, so that it can be considered as a generalization of χ{sup 2}.

  15. DOE - Office of Legacy Management -- Morse Chemical Co - IL 0-05

    Office of Legacy Management (LM)

    Morse Chemical Co - IL 0-05 FUSRAP Considered Sites Site: MORSE CHEMICAL CO. (IL.0-05 ) Eliminated from consideration under FUSRAP Designated Name: Not Designated Alternate Name: None Location: 8 South Michigan Avenue , Chicago , Illinois IL.05-1 Evaluation Year: 1987 IL.05-3 Site Operations: Submitted a bid to AEC for thorium work; proposal was not accepted; no indication work done for a DOE predecessor at this site. IL.05-3 Site Disposition: Eliminated - No Authority - No work for a DOE

  16. Constraints on the progenitor system of the type Ia supernova 2014J from pre-explosion Hubble space telescope imaging

    SciTech Connect (OSTI)

    Kelly, Patrick L.; Fox, Ori D.; Filippenko, Alexei V.; Shen, Ken J.; Zheng, WeiKang; Graham, Melissa L.; Tucker, Brad E.; Cenko, S. Bradley; Schaefer, Gail

    2014-07-20

    We constrain the properties of the progenitor system of the highly reddened Type Ia supernova (SN Ia) 2014J in Messier 82 (M82; d ? 3.5 Mpc). We determine the supernova (SN) location using Keck-II K-band adaptive optics images, and we find no evidence for flux from a progenitor system in pre-explosion near-ultraviolet through near-infrared Hubble Space Telescope (HST) images. Our upper limits exclude systems having a bright red giant companion, including symbiotic novae with luminosities comparable to that of RS Ophiuchi. While the flux constraints are also inconsistent with predictions for comparatively cool He-donor systems (T ? 35,000 K), we cannot preclude a system similar to V445 Puppis. The progenitor constraints are robust across a wide range of R{sub V} and A{sub V} values, but significantly greater values than those inferred from the SN light curve and spectrum would yield proportionally brighter luminosity limits. The comparatively faint flux expected from a binary progenitor system consisting of white dwarf stars would not have been detected in the pre-explosion HST imaging. Infrared HST exposures yield more stringent constraints on the luminosities of very cool (T < 3000 K) companion stars than was possible in the case of SN Ia 2011fe.

  17. Metabolomic profiling of the nectars of Aquilegia pubescens and <i>A. Canadensis

    SciTech Connect (OSTI)

    Noutsos, Christos; Perera, Ann M.; Nikolau, Basil J.; Seaver, Samuel M. D.; Ware, Doreen H.; Motta, Andrea

    2015-05-01

    To date, variation in nectar chemistry of flowering plants has not been studied in detail. Such variation exerts considerable influence on pollinator–plant interactions, as well as on flower traits that play important roles in the selection of a plant for visitation by specific pollinators. Over the past 60 years the Aquilegia genus has been used as a key model for speciation studies. In this study, we defined the metabolomic profiles of flower samples of two Aquilegia species, <i>A. Canadensis and <i>A. pubescens. We identified a total of 75 metabolites that were classified into six main categories: organic acids, fatty acids, amino acids, esters, sugars, and unknowns. The mean abundances of 25 of these metabolites were significantly different between the two species, providing insights into interspecies variation in floral chemistry. Using the PlantSEED biochemistry database, we found that the majority of these metabolites are involved in biosynthetic pathways. Finally, we explored the annotated genome of <i>A. coerulea, using the PlantSEED pipeline and reconstructed the metabolic network of Aquilegia. This network, which contains the metabolic pathways involved in generating the observed chemical variation, is now publicly available from the DOE Systems Biology Knowledge Base (KBase; http://kbase.us).

  18. Spectroscopic Properties of Star-Forming Host Galaxies and Type Ia Supernova Hubble Residuals in a Nearly Unbiased Sample

    SciTech Connect (OSTI)

    D'Andrea, Chris B.; et al.

    2011-12-20

    We examine the correlation between supernova host galaxy properties and their residuals on the Hubble diagram. We use supernovae discovered during the Sloan Digital Sky Survey II - Supernova Survey, and focus on objects at a redshift of z < 0.15, where the selection effects of the survey are known to yield a complete Type Ia supernova sample. To minimize the bias in our analysis with respect to measured host-galaxy properties, spectra were obtained for nearly all hosts, spanning a range in magnitude of -23 < M_r < -17. In contrast to previous works that use photometric estimates of host mass as a proxy for global metallicity, we analyze host-galaxy spectra to obtain gas-phase metallicities and star-formation rates from host galaxies with active star formation. From a final sample of ~ 40 emission-line galaxies, we find that light-curve corrected Type Ia supernovae are ~ 0.1 magnitudes brighter in high-metallicity hosts than in low-metallicity hosts. We also find a significant (> 3{\\sigma}) correlation between the Hubble residuals of Type Ia supernovae and the specific star-formation rate of the host galaxy. We comment on the importance of supernova/host-galaxy correlations as a source of systematic bias in future deep supernova surveys.

  19. A POSSIBLE EVOLUTIONARY SCENARIO OF HIGHLY MAGNETIZED SUPER-CHANDRASEKHAR WHITE DWARFS: PROGENITORS OF PECULIAR TYPE Ia SUPERNOVAE

    SciTech Connect (OSTI)

    Das, Upasana; Mukhopadhyay, Banibrata; Rao, A. R. E-mail: bm@physics.iisc.ernet.in

    2013-04-10

    Several recently discovered peculiar Type Ia supernovae seem to demand an altogether new formation theory that might help explain the puzzling dissimilarities between them and the standard Type Ia supernovae. The most striking aspect of the observational analysis is the necessity of invoking super-Chandrasekhar white dwarfs having masses {approx}2.1-2.8 M{sub Sun }, M{sub Sun} being the mass of Sun, as their most probable progenitors. Strongly magnetized white dwarfs having super-Chandrasekhar masses have already been established as potential candidates for the progenitors of peculiar Type Ia supernovae. Owing to the Landau quantization of the underlying electron degenerate gas, theoretical results yielded the observationally inferred mass range. Here, we sketch a possible evolutionary scenario by which super-Chandrasekhar white dwarfs could be formed by accretion on to a commonly observed magnetized white dwarf, invoking the phenomenon of flux freezing. This opens multiple possible evolution scenarios ending in supernova explosions of super-Chandrasekhar white dwarfs having masses within the range stated above. We point out that our proposal has observational support, such as the recent discovery of a large number of magnetized white dwarfs by the Sloan Digital Sky Survey.

  20. Radiogenic p-isotopes from type Ia supernova, nuclear physics uncertainties, and galactic chemical evolution compared with values in primitive meteorites

    SciTech Connect (OSTI)

    Travaglio, C.; Gallino, R.; Rauscher, T.; Dauphas, N.; Rpke, F. K.; Hillebrandt, W. E-mail: claudia.travaglio@b2fh.org

    2014-11-10

    The nucleosynthesis of proton-rich isotopes is calculated for multi-dimensional Chandrasekhar-mass models of Type Ia supernovae (SNe Ia) with different metallicities. The predicted abundances of the short-lived radioactive isotopes {sup 92}Nb, {sup 97,} {sup 98}Tc, and {sup 146}Sm are given in this framework. The abundance seeds are obtained by calculating s-process nucleosynthesis in the material accreted onto a carbon-oxygen white dwarf from a binary companion. A fine grid of s-seeds at different metallicities and {sup 13}C-pocket efficiencies is considered. A galactic chemical evolution model is used to predict the contribution of SN Ia to the solar system p-nuclei composition measured in meteorites. Nuclear physics uncertainties are critical to determine the role of SNe Ia in the production of {sup 92}Nb and {sup 146}Sm. We find that, if standard Chandrasekhar-mass SNe Ia are at least 50% of all SN Ia, they are strong candidates for reproducing the radiogenic p-process signature observed in meteorites.

  1. Magnetic domain tuning and the emergence of bubble domains in the bilayer manganite La<mn>2mn>->2mn>xSr<mn>1mn>+>2mn>xMn>2mn>O>7mn>(x=<mn>0.32mn>)

    SciTech Connect (OSTI)

    Jeong, Juyoung; Yang, Ilkyu; Yang, Jinho; Ayala-Valenzuela, Oscar E.; Wulferding, Dirk; Zhou, J. -S.; Goodenough, John B.; de Lozanne, Alex; Mitchell, J. F.; Leon, Neliza; Movshovich, Roman; Jeong, Yoon Hee; Yeom, Han Woong; Kim, Jeehoon

    2015-08-17

    Here, we report a magnetic force microscopy study of the magnetic domain evolution in the layered manganite La2–2xSr1+2xMn2O7 (with x = 0.32). This strongly correlated electron compound is known to exhibit a wide range of magnetic phases, including a recently uncovered biskyrmion phase. We observe a continuous transition from dendritic to stripelike domains, followed by the formation of magnetic bubbles due to a field- and temperature-dependent competition between in-plane and out-of-plane spin alignments. The magnetic bubble phase appears at comparable field and temperature ranges as the biskyrmion phase, suggesting a close relation between both phases. Based on our real-space images we construct a temperature-field phase diagram for this composition.

  2. #iWNCD W ONTAININO Il@MQWm;

    Office of Legacy Management (LM)

    decontmlmtlon proceam takee longer than originally anticipated 'U&e order .are urgently required to prevent a shutdown. "Z, mo-1 ' 2lda.p - from 4a6-55 to a possible 4-5-55 based on the receipt of vendor's plantby 1-22-55. #iWNCD W ONTAININO Il@MQWm; ;g hours worked; Hours worked will be observed and under the control of . . M%-.'E.Section . (Copy of Vendorts letter of quotation dated l/5/55 is VAWNWWXlINALORDEt :Y $ u(,507.60 upoDRpuiI9APPROPAk &movND* 0 3375.00 (rllaxlmum) Field

  3. CaMn2Al10: Itinerant Mn magnetism on the verge of magnetic order

    SciTech Connect (OSTI)

    Steinke, L.; Simonson, J. W.; Yin, W. -G.; Smith, G. J.; Kistner-Morris, J. J.; Zellman, S.; Puri, A.; Aronson, M. C.

    2015-07-24

    We report the discovery of CaMn2Al10, a metal with strong magnetic anisotropy and moderate electronic correlations. Magnetization measurements find a Curie-Weiss moment of 0.83μB/Mn, significantly reduced from the Hund's rule value, and the magnetic entropy obtained from specific heat measurements is correspondingly small, only ≈ 9% of Rln2. These results imply that the Mn magnetism is highly itinerant, a conclusion supported by density functional theory calculations that find strong Mn-Al hybridization. Consistent with the layered nature of the crystal structure, the magnetic susceptibility χ is anisotropic below 20 K, with a maximum ratio of χ[010][001] ≈ 3.5. A strong power-law divergence χ(T) ~ T–1.2 below 20 K implies incipient ferromagnetic order, an Arrott plot analysis of the magnetization suggests a vanishing low Curie temperature TC ~ 0. Our experiments indicate that CaMn2Al10 is a rare example of a system where the weak and itinerant Mn-based magnetism is poised on the verge of order.

  4. THE DETONATION MECHANISM OF THE PULSATIONALLY ASSISTED GRAVITATIONALLY CONFINED DETONATION MODEL OF Type Ia SUPERNOVAE

    SciTech Connect (OSTI)

    Jordan, G. C. IV; Graziani, C.; Weide, K.; Norris, J.; Hudson, R.; Lamb, D. Q.; Fisher, R. T.; Townsley, D. M.; Meakin, C.; Reid, L. B.

    2012-11-01

    We describe the detonation mechanism composing the 'pulsationally assisted' gravitationally confined detonation (GCD) model of Type Ia supernovae. This model is analogous to the previous GCD model reported in Jordan et al.; however, the chosen initial conditions produce a substantively different detonation mechanism, resulting from a larger energy release during the deflagration phase. The resulting final kinetic energy and {sup 56}Ni yields conform better to observational values than is the case for the 'classical' GCD models. In the present class of models, the ignition of a deflagration phase leads to a rising, burning plume of ash. The ash breaks out of the surface of the white dwarf, flows laterally around the star, and converges on the collision region at the antipodal point from where it broke out. The amount of energy released during the deflagration phase is enough to cause the star to rapidly expand, so that when the ash reaches the antipodal point, the surface density is too low to initiate a detonation. Instead, as the ash flows into the collision region (while mixing with surface fuel), the star reaches its maximally expanded state and then contracts. The stellar contraction acts to increase the density of the star, including the density in the collision region. This both raises the temperature and density of the fuel-ash mixture in the collision region and ultimately leads to thermodynamic conditions that are necessary for the Zel'dovich gradient mechanism to produce a detonation. We demonstrate feasibility of this scenario with three three-dimensional (3D), full star simulations of this model using the FLASH code. We characterized the simulations by the energy released during the deflagration phase, which ranged from 38% to 78% of the white dwarf's binding energy. We show that the necessary conditions for detonation are achieved in all three of the models.

  5. Persistent C II absorption in the normal type Ia supernova 2002fk

    SciTech Connect (OSTI)

    Cartier, Rgis; Zelaya, Paula [Millennium Institute of Astrophysics, Casilla 36-D, Santiago (Chile); Hamuy, Mario; Maza, Jos; Gonzlez, Luis; Huerta, Leonor [Departamento de Astronoma, Universidad de Chile, Casilla 36-D, Santiago (Chile); Pignata, Giuliano [Departamento Ciencias Fisicas, Universidad Andres Bello, Av. Repblica 252, Santiago (Chile); Frster, Francisco [Center for Mathematical Modelling, Universidad de Chile, Avenida Blanco Encalada 2120, Piso 7, Santiago (Chile); Folatelli, Gaston [Institute for the Physics and Mathematics of the Universe (IPMU), University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8583 (Japan); Phillips, Mark M.; Morrell, Nidia; Contreras, Carlos; Roth, Miguel; Gonzlez, Sergio [Carnegie Institution of Washington, Las Campanas Observatory, Colina el Pino s/n, Casilla 601 (Chile); Krisciunas, Kevin; Suntzeff, Nicholas B. [Department of Physics and Astronomy, Texas A and M University, 4242 TAMU, College Station, TX 77843 (United States); Clocchiatti, Alejandro [Departamento de Astronoma y Astrofsica, Pontificia Universidad Catlica de Chile, Casilla 306, Santiago (Chile); Coppi, Paolo [Department of Astronomy, Yale University, New Haven, CT 06520-8101 (United States); Koviak, Kathleen, E-mail: rcartier@das.uchile.cl [Carnegie Institution of Washington, 813 Santa Barbara Street, Pasadena, CA 911901 (United States)

    2014-07-01

    We present well-sampled UBVRIJHK photometry of SN 2002fk starting 12 days before maximum light through 122 days after peak brightness, along with a series of 15 optical spectra from 4 to +95 days since maximum. Our observations show the presence of C II lines in the early-time spectra of SN 2002fk, expanding at 11,000 km s{sup 1} and persisting until 8 days past maximum light with a velocity of ?9000 km s{sup 1}. SN 2002fk is characterized by a small velocity gradient of v-dot {sub Si} {sub II}=26 km s{sup 1} day{sup 1}, possibly caused by an off-center explosion with the ignition region oriented toward the observer. The connection between the viewing angle of an off-center explosion and the presence of C II in the early-time spectrum suggests that the observation of C II could be also due to a viewing angle effect. Adopting the Cepheid distance to NGC 1309 we provide the first H {sub 0} value based on near-infrared (near-IR) measurements of a Type Ia supernova (SN) between 63.0 0.8 (3.4 systematic) and 66.7 1.0 (3.5 systematic) km s{sup 1} Mpc{sup 1}, depending on the absolute magnitude/decline rate relationship adopted. It appears that the near-IR yields somewhat lower (6%-9%) H {sub 0} values than the optical. It is essential to further examine this issue by (1) expanding the sample of high-quality near-IR light curves of SNe in the Hubble flow, and (2) increasing the number of nearby SNe with near-IR SN light curves and precise Cepheid distances, which affords the promise to deliver a more precise determination of H {sub 0}.

  6. Strong enhancement of s -wave superconductivity near a quantum critical point of Ca<mn>3mn>Ir>4mn>Sn>13mn>

    SciTech Connect (OSTI)

    Biswas, P. K.; Guguchia, Z.; Khasanov, R.; Chinotti, M.; Li, L.; Wang, Kefeng; Petrovic, C.; Morenzoni, E.

    2015-11-11

    We report microscopic studies by muon spin rotation/relaxation as a function of pressure of the Ca<mn>3mn>Ir>4mn>Sn>13mn> and Sr3Ir4Sn13 system displaying superconductivity and a structural phase transition associated with the formation of a charge density wave (CDW). Our findings show a strong enhancement of the superfluid density and a dramatic increase of the pairing strength above a pressure of ≈ 1.6 GPa giving direct evidence of the presence of a quantum critical point separating a superconducting phase coexisting with CDW from a pure superconducting phase. The superconducting order parameter in both phases has the same s-wave symmetry. In spite of the conventional phonon-mediated BCS character of the weakly correlated (Ca1-xSrx)3Ir4Sn13 system the dependence of the effective superfluid density on the critical temperature puts this compound in the “Uemura” plot close to unconventional superconductors. This system exemplifies that conventional BCS superconductors in the presence of competing orders or multi-band structure can also display characteristics of unconventional superconductors.

  7. Mn-Fe base and Mn-Cr-Fe base austenitic alloys

    DOE Patents [OSTI]

    Brager, Howard R.; Garner, Francis A.

    1987-01-01

    Manganese-iron base and manganese-chromium-iron base austenitic alloys designed to have resistance to neutron irradiation induced swelling and low activation have the following compositions (in weight percent): 20 to 40 Mn; up to about 15 Cr; about 0.4 to about 3.0 Si; an austenite stabilizing element selected from C and N, alone or in combination with each other, and in an amount effective to substantially stabilize the austenite phase, but less than about 0.7 C, and less than about 0.3 N; up to about 2.5 V; up to about 0.1 P; up to about 0.01 B; up to about 3.0 Al; up to about 0.5 Ni; up to about 2.0 W; up to about 1.0 Ti; up to about 1.0 Ta; and with the remainder of the alloy being essentially iron.

  8. MID-IR SPECTRA OF TYPE Ia SN 2014J IN M82 SPANNING THE FIRST 4 MONTHS

    SciTech Connect (OSTI)

    Telesco, Charles M.; Li, Dan; Barnes, Peter J.; Mariñas, Naibí; Zhang, Han; Höflich, Peter; Álvarez, Carlos; Fernández, Sergio; Rebolo, Rafael; Hough, James H.; Levenson, N. A.; Pantin, Eric; Roche, Patrick E-mail: phoeflich77@gmail.com

    2015-01-10

    We present a time series of 8-13 μm spectra and photometry for SN 2014J obtained 57, 81, 108, and 137 days after the explosion using CanariCam on the Gran Telescopio Canarias. This is the first mid-IR time series ever obtained for a Type Ia supernova (SN Ia). These observations can be understood within the framework of the delayed detonation model and the production of ∼0.6 M {sub ☉} of {sup 56}Ni, consistent with the observed brightness, the brightness decline relation, and the γ-ray fluxes. The [Co III] line at 11.888 μm is particularly useful for evaluating the time evolution of the photosphere and measuring the amount of {sup 56}Ni and thus the mass of the ejecta. Late-time line profiles of SN 2014J are rather symmetric and not shifted in the rest frame. We see argon emission, which provides a unique probe of mixing in the transition layer between incomplete burning and nuclear statistical equilibrium. We may see [Fe III] and [Ni IV] emission, both of which are observed to be substantially stronger than indicated by our models. If the latter identification is correct, then we are likely observing stable Ni, which might imply central mixing. In addition, electron capture, also required for stable Ni, requires densities larger than ∼1 × 10{sup 9} g cm{sup –3}, which are expected to be present only in white dwarfs close to the Chandrasekhar limit. This study demonstrates that mid-IR studies of SNe Ia are feasible from the ground and provide unique information, but it also indicates the need for better atomic data.

  9. Systematic uncertainties associated with the cosmological analysis of the first Pan-STARRS1 type Ia supernova sample

    SciTech Connect (OSTI)

    Scolnic, D.; Riess, A.; Brout, D.; Rodney, S. [Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States); Rest, A. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Huber, M. E.; Tonry, J. L. [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Foley, R. J.; Chornock, R.; Berger, E.; Soderberg, A. M.; Stubbs, C. W.; Kirshner, R. P.; Challis, P.; Czekala, I.; Drout, M. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Narayan, G. [Department of Physics, Harvard University, 17 Oxford Street, Cambridge, MA 02138 (United States); Smartt, S. J.; Botticella, M. T. [Astrophysics Research Centre, School of Mathematics and Physics, Queens University Belfast, Belfast BT7 1NN (United Kingdom); Schlafly, E. [Max Planck Institute for Astronomy, Konigstuhl 17, D-69117 Heidelberg (Germany); and others

    2014-11-01

    We probe the systematic uncertainties from the 113 Type Ia supernovae (SN Ia) in the Pan-STARRS1 (PS1) sample along with 197 SN Ia from a combination of low-redshift surveys. The companion paper by Rest et al. describes the photometric measurements and cosmological inferences from the PS1 sample. The largest systematic uncertainty stems from the photometric calibration of the PS1 and low-z samples. We increase the sample of observed Calspec standards from 7 to 10 used to define the PS1 calibration system. The PS1 and SDSS-II calibration systems are compared and discrepancies up to ?0.02 mag are recovered. We find uncertainties in the proper way to treat intrinsic colors and reddening produce differences in the recovered value of w up to 3%. We estimate masses of host galaxies of PS1 supernovae and detect an insignificant difference in distance residuals of the full sample of 0.037 0.031 mag for host galaxies with high and low masses. Assuming flatness and including systematic uncertainties in our analysis of only SNe measurements, we find w =?1.120{sub ?0.206}{sup +0.360}(Stat){sub ?0.291}{sup +0.269}(Sys). With additional constraints from Baryon acoustic oscillation, cosmic microwave background (CMB) (Planck) and H {sub 0} measurements, we find w=?1.166{sub ?0.069}{sup +0.072} and ?{sub m}=0.280{sub ?0.012}{sup +0.013} (statistical and systematic errors added in quadrature). The significance of the inconsistency with w = 1 depends on whether we use Planck or Wilkinson Microwave Anisotropy Probe measurements of the CMB: w{sub BAO+H0+SN+WMAP}=?1.124{sub ?0.065}{sup +0.083}.

  10. Structure and magnetic properties of LnMnSbO ( Ln=La and Ce)

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

    Zhang, Qiang; Kumar, C. M. N.; Tian, Wei; Dennis, Kevin W.; Goldman, Alan I.; Vaknin, David

    2016-03-11

    Here, a neutron powder diffraction (NPD) study of LnMnSbO (Ln = La or Ce) reveals differences between the magnetic ground state of the two compounds due to the strong Ce-Mn coupling compared to La-Mn. The two compounds adopt the P4/nmm space group down to 2 K, and whereas magnetization measurements do not show obvious anomaly at high temperatures, NPD reveals a C-type antiferromagnetic (AFM) order below TN = 255K for LaMnSbO and 240 K for CeMnSbO. While the magnetic structure of LaMnSbO is preserved to base temperature, a sharp transition at TSR = 4.5K is observed in CeMnSbO due tomore » a spin-reorientation (SR) transition of the Mn2+ magnetic moments from pointing along the c axis to the ab plane. The SR transition in CeMnSbO is accompanied by a simultaneous long-range AFM ordering of the Ce moments, which indicates that the Mn SR transition is driven by the Ce-Mn coupling. The ordered moments are found to be somewhat smaller than those expected for Mn2+ (S = 5/2) in insulators, but large enough to suggest that these compounds belong to the class of local-moment antiferromagnets. The lower TN found in these two compounds compared to the As-based counterparts (TN = 317 for LaMnAsO, TN = 347K for CeMnAsO) indicates that the Mn-Pn (Pn=As or Sb) hybridization that mediates the superexchange Mn-Pn-Mn coupling is weaker for the Sb-based compounds.« less

  11. Revealing the Restructured Surface of Li[Mn2]O4

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

    Amos, Charles D.; Roldan, Manuel A.; Varela, Maria; Goodenough, John B.; Ferreira, Paulo J.

    2016-03-29

    The spinel Revealing the Restructured Surface of Li[Mn2]O4 is a candidate cathode for a Li-ion battery, but its capacity fades over a charge/discharge cycle of Li1–x[Mn2]O4 (0 < x < 1) that is associated with a loss of Mn to the organic-liquid electrolyte. It is known that the disproportionation reaction 2Mn3+ = Mn2+ + Mn4+ occurs at the surface of a Mn spinel, and it is important to understand the atomic structure and composition of the surface of Revealing the Restructured Surface of Li[Mn2]O4 in order to understand how Mn loss occurs. We report a study of the surface reconstructionmore » of Revealing the Restructured Surface of Li[Mn2]O4 by aberration-corrected scanning transmission electron microscopy. The atomic structure coupled with Mn-valence and the distribution of the atomic ratio of oxygen obtained by electron energy loss spectroscopy reveals a thin, stable surface layer of Mn3O4, a subsurface region of Li1+x[Mn2]O4 with retention of bulk Li[Mn2]O4. We conclude that this observation is compatible with the disproportionation reaction coupled with oxygen deficiency and a displacement of surface Li+ from the Mn3O4 surface phase. These results provide a critical step toward understanding how Mn is lost from Li[Mn2]O4, once inside a battery.« less

  12. Synthesis, characterization and electrochemical performance of Al-substituted Li₂MnO₃

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

    Dhital, Chetan; Huq, Ashfia; Paranthaman, Mariappan Parans; Manivannan, Ayyakkannu; Torres-Castro, Loraine; Shojan, Jifi; Julien, Christian M.; Katiyar, Ram S.

    2015-08-08

    Li2MnO3 is known to be electrochemically inactive due to Mn in tetravalent oxidation state. Several compositions such as Li2MnO3 , Li1.5Al0.17MnO3, Li1.0Al0.33MnO3 and Li0.5Al0.5MnO3 were synthesized by a sol–gel Pechini method. All the samples were characterized with x-ray diffraction, Raman, x-ray photoelectron spectroscopy, scanning electron microscopy, Tap density and BET analyzer. X-ray diffraction patterns indicated the presence of monoclinic phase for pristine Li2MnO3and mixed monoclinic/spinel phases (Li2 - xMn1 - yAlx + yO3 + z) for Al-substituted Li2MnO3compounds. The Al substitution seems to occur both at Li and Mn sites, which could explain the presence of spinel phase. X-ray photoelectronmore » spectroscopy for Mn 2p orbital reveals a significant decrease in binding energy for Li1.0Al0.33MnO3 and Li0.5Al0.5MnO3 compounds. Cyclic voltammetry, charge/discharge cycles and electrochemical impedance spectroscopy were also performed. A discharge capacity of 24 mAh g-1 for Li2MnO3, 68 mAh g-1 for Li1.5Al0.17MnO3, 58 mAh g-1 for Li1.0Al0.33MnO3 and 74 mAh g-1 for Li0.5Al0.5MnO3 were obtained. As a result, aluminum substitutions increased the formation of spinel phase which is responsible for cycling.« less

  13. Resonant spin tunneling in randomly oriented nanospheres of Mn?? acetate

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

    Lendinez, S.; Billinge, S. J. L.; Zarzuela, R.; Tejada, J.; Terban, M. W.; Espin, J.; Imaz, I.; Maspoch, D.; Chudnovsky, E. M.

    2015-01-06

    We report measurements and theoretical analysis of resonant spin tunneling in randomly oriented nanospheres of a molecular magnet. Amorphous nanospheres of Mn?? acetate have been fabricated and characterized by chemical, infrared, TEM, X-ray, and magnetic methods. Magnetic measurements have revealed sharp tunneling peaks in the field derivative of the magnetization that occur at the typical resonant field values for the Mn?? acetate crystal in the field parallel to the easy axis.Theoretical analysis is provided that explains these observations. We argue that resonant spin tunneling in a molecular magnet can be established in a powder sample, without the need for amoresingle crystal and without aligning the easy magnetization axes of the molecules. This is confirmed by re-analyzing the old data on a powdered sample of non-oriented micron-size crystals of Mn?? acetate. Our findings can greatly simplify the selection of candidates for quantum spin tunneling among newly synthesized molecular magnets.less

  14. Nearby Supernova Factory Observations of SN 2005gj: Another TypeIa Supernova in a Massive Circumstellar Envelope

    SciTech Connect (OSTI)

    Aldering, G.; Antilogus, P.; Bailey, S.; Baltay, C.; Bauer, A.; Blanc, N.; Bongard, S.; Copin, Y.; Gangler, E.; Gilles, S.; Kessler, R.; Kocevski, D.; Lee, B.C.; Loken, S.; Nugent, P.; Pain, R.; Pecontal, E.; Pereira, R.; Perlmutter, S.; Rabinowitz, D.; Rigaudier, G.; Scalzo, R.; Smadja, G.; Thomas, R.C.; Wang, L.; Weaver, B.A.; Rabinowitz, D.; Bauer, A.

    2006-06-01

    We report the independent discovery and follow-up observations of supernova 2005gj by the Nearby Supernova Factory. This is the second confirmed case of a ''hybrid'' Type Ia/IIn supernova, which like the prototype SN 2002ic, we interpret as the explosion of a white dwarf interacting with a circumstellar medium. Our early-phase photometry of SN 2005gj shows that the strength of the interaction between the supernova ejecta and circumstellar material is much stronger than for SN 2002ic. Our .rst spectrum shows a hot continuum with broad and narrow H{alpha} emission. Later spectra, spanning over 4 months from outburst, show clear Type Ia features combined with broad and narrow H{gamma}, H{beta},H{alpha} and He I {lambda}{lambda}5876,7065 in emission. At higher resolution, P Cygni profiles are apparent. Surprisingly, we also observe an inverted P Cygni profile for [O III] {lambda}5007. We find that the lightcurve and measured velocity of the unshocked circumstellar material imply mass loss as recently as 8 years ago. This is in contrast to SN 2002ic, for which an inner cavity in the circumstellar material was inferred. Within the context of the thin-shell approximation, the early lightcurve is well-described by a flat radial density profile for the circumstellar material. However, our decomposition of the spectra into Type Ia and shock emission components allows for little obscuration of the supernova, suggesting an aspherical or clumpy distribution for the circumstellar material. We suggest that the emission line velocity profiles arise from electron scattering rather than the kinematics of the shock. This is supported by the inferred high densities, and the lack of evidence for evolution in the line widths. Ground- and space-based photometry, and Keck spectroscopy, of the host galaxy are used to ascertain that the host galaxy has low metallicity (Z/Z{sub {circle_dot}} < 0.3; 95% confidence) and that this galaxy is undergoing a significant star formation event that

  15. ENVIRONMENTAL IlONITORING REPORT FOR THE NEVADA TEST SITE AND...

    Office of Legacy Management (LM)

    IlONITORING REPORT FOR THE NEVADA TEST SITE AND OTHER TEST AREAS USED FOR UNDERGROUND NUCLEAR DETONATIONS January through December 1975 Nonitoring Operations Division Environmental ...

  16. Association study of schizophrenia and IL-2 receptor {beta} chain gene

    SciTech Connect (OSTI)

    Nimgaonkar, V.L.; Yang, Z.W.; Zhang, X.R.; Brar, J.S.

    1995-10-09

    A case-control association study was conducted in Caucasian patients with schizophrenia (DSM-III-R, n = 42) and unaffected controls (n = 47) matched for ethnicity and area of residence. Serum interleukin-2 receptor (IL-2R) concentrations, as well as a dinucleotide repeat polymorphism in the IL-2RP chain gene, were examined in both groups. No significant differences in IL-2R concentrations or in the distribution of the polymorphism were noted. This study does not support an association between schizophrenia and the IL-2RP gene locus, contrary to the suggestive evidence from linkage analysis in multicase families. 17 refs., 2 tabs.

  17. DISPLAYING THE HETEROGENEITY OF THE SN 2002cx-LIKE SUBCLASS OF TYPE Ia SUPERNOVAE WITH OBSERVATIONS OF THE Pan-STARRS-1 DISCOVERED SN 2009ku

    SciTech Connect (OSTI)

    Narayan, G.; Foley, R. J.; Berger, E.; Chornock, R.; Rest, A.; Soderberg, A. M.; Kirshner, R. P.; Botticella, M. T.; Smartt, S.; Valenti, S.; Huber, M. E.; Scolnic, D.; Grav, T.; Burgett, W. S.; Chambers, K. C.; Flewelling, H. A.; Gates, G.; Kaiser, N.; Magnier, E. A.; Morgan, J. S. E-mail: rfoley@cfa.harvard.edu

    2011-04-10

    SN 2009ku, discovered by Pan-STARRS-1, is a Type Ia supernova (SN Ia), and a member of the distinct SN 2002cx-like class of SNe Ia. Its light curves are similar to the prototypical SN 2002cx, but are slightly broader and have a later rise to maximum in g. SN 2009ku is brighter ({approx}0.6 mag) than other SN 2002cx-like objects, peaking at M{sub V} = -18.4 mag, which is still significantly fainter than typical SNe Ia. SN 2009ku, which had an ejecta velocity of {approx}2000 km s{sup -1} at 18 days after maximum brightness, is spectroscopically most similar to SN 2008ha, which also had extremely low-velocity ejecta. However, SN 2008ha had an exceedingly low luminosity, peaking at M{sub V} = -14.2 mag, {approx}4 mag fainter than SN 2009ku. The contrast of high luminosity and low ejecta velocity for SN 2009ku is contrary to an emerging trend seen for the SN 2002cx class. SN 2009ku is a counterexample of a previously held belief that the class was more homogeneous than typical SNe Ia, indicating that the class has a diverse progenitor population and/or complicated explosion physics. As the first example of a member of this class of objects from the new generation of transient surveys, SN 2009ku is an indication of the potential for these surveys to find rare and interesting objects.

  18. Stress induced anisotropy in CoFeMn soft magnetic nanocomposites...

    Office of Scientific and Technical Information (OSTI)

    Journal Article: Stress induced anisotropy in CoFeMn soft magnetic nanocomposites Citation Details In-Document Search Title: Stress induced anisotropy in CoFeMn soft magnetic ...

  19. Pulsed laser deposition of Mn doped CdSe quantum dots for improved solar cell performance

    SciTech Connect (OSTI)

    Dai, Qilin; Wang, Wenyong E-mail: jtang2@uwyo.edu; Tang, Jinke E-mail: jtang2@uwyo.edu; Sabio, Erwin M.

    2014-05-05

    In this work, we demonstrate (1) a facile method to prepare Mn doped CdSe quantum dots (QDs) on Zn{sub 2}SnO{sub 4} photoanodes by pulsed laser deposition and (2) improved device performance of quantum dot sensitized solar cells of the Mn doped QDs (CdSe:Mn) compared to the undoped QDs (CdSe). The band diagram of photoanode Zn{sub 2}SnO{sub 4} and sensitizer CdSe:Mn QD is proposed based on the incident-photon-to-electron conversion efficiency (IPCE) data. Mn-modified band structure leads to absorption at longer wavelengths than the undoped CdSe QDs, which is due to the exchange splitting of the CdSe:Mn conduction band by the Mn dopant. Three-fold increase in the IPCE efficiency has also been observed for the Mn doped samples.

  20. Pulsed laser deposition of Mn doped CdSe quantum dots for improved...

    Office of Scientific and Technical Information (OSTI)

    Pulsed laser deposition of Mn doped CdSe quantum dots for improved solar cell performance Citation Details In-Document Search Title: Pulsed laser deposition of Mn doped CdSe ...

  1. Coexistence of charge-density wave and ferromagnetism in Ni2MnGa...

    Office of Scientific and Technical Information (OSTI)

    Coexistence of charge-density wave and ferromagnetism in Ni2MnGa Citation Details In-Document Search Title: Coexistence of charge-density wave and ferromagnetism in Ni2MnGa ...

  2. Mixing antiferromagnets to tune NiFe-[IrMn/FeMn] interfacial spin-glasses, grains thermal stability, and related exchange bias properties

    SciTech Connect (OSTI)

    Akmaldinov, K.; Ducruet, C.; Portemont, C.; Joumard, I.; Prejbeanu, I. L.; Dieny, B.; Baltz, V.

    2014-05-07

    Spintronics devices and in particular thermally assisted magnetic random access memories require a wide range of ferromagnetic/antiferromagnetic (F/AF) exchange bias (EB) properties and subsequently of AF materials to fulfil diverse functionality requirements for the reference and storage. For the reference layer, large EB energies and high blocking temperature (T{sub B}) are required. In contrast, for the storage layer, mostly moderate T{sub B} are needed. One of the present issues is to find a storage layer with properties intermediate between those of IrMn and FeMn and in particular: (i) with a T{sub B} larger than FeMn for better stability at rest-T but lower than IrMn to reduce power consumption at write-T and (ii) with improved magnetic interfacial quality, i.e., with reduced interfacial glassy character for lower properties dispersions. To address this issue, the EB properties of F/AF based stacks were studied for various mixed [IrMn/FeMn] AFs. In addition to EB loop shifts, the F/AF magnetic interfacial qualities and the AF grains thermal stability are probed via measurements of the low- and high-temperature contributions to the T{sub B} distributions, respectively. A tuning of the above three parameters is observed when evolving from IrMn to FeMn via [IrMn/FeMn] repetitions.

  3. Analysis of natural gases, AL, AR, FL, GA, IL, IN, IA, KY, LA, MD, MI, MS, MO, NJ, NY, NC, OH, PA, TN, VA, and WV; 1951-1991 (for microcomputers). Data file

    SciTech Connect (OSTI)

    Not Available

    1991-01-01

    The U.S. Bureau of Mines diskette contains analysis and related source data for 2,357 natural gas samples collected from miscellaneous states, which include the following states: Alabama, Arkansas (except Arkoma Basin), Florida, Georgia, Illinois, Indiana, Iowa, Kentucky, Louisiana, Maryland, Michigan, Mississippi, Missouri, New Jersey, New York, North Carolina, Ohio, Pennsylvania, Tennessee, Virginia, and West Virginia. All samples were obtained and analyzed as part of the Bureau's investigations of occurrences of helium in natural gases of countries with free market economies. The survey has been conducted since 1917. The analysis contained on the diskette contain the full range of component analysis data. Five files are on the diskette: READ.ME, MISC.TXT, MISC.DBF, USHEANAL.DBF, and BASINCDE.TXT.

  4. Epitaxial Growth of Intermetallic MnPt Films on Oxides and Large Exchange Bias

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

    Liu, Zhiqi; Biegalski, Michael D.; Hsu, Shang-Lin; Shang, Shunli; Marker, Cassie; Liu, Jian; Li, Li; Fan, Lisha S.; Meyer, Tricia L.; Wong, Anthony T.; et al

    2015-11-05

    High-quality epitaxial growth of intermetallic MnPt films on oxides is achieved, with potential for multiferroic heterostructure applications. Antisite-stabilized spin-flipping induces ferromagnetism in MnPt films, although it is robustly antiferromagnetic in bulk. Moreover, highly ordered antiferromagnetic MnPt films exhibit superiorly large exchange coupling with a ferromagnetic layer.

  5. Epitaxial growth of intermetallic MnPt films on oxides and large exchange bias

    SciTech Connect (OSTI)

    Liu, Zhiqi; Biegalski, Michael D.; Hsu, Shang-Lin; Shang, Shunli; Marker, Cassie; Liu, Jian; Li, Li; Fan, Lisha S.; Meyer, Tricia L.; Wong, Anthony T.; Nichols, John A.; Chen, Deyang; You, Long; Chen, Zuhuang; Wang, Kai; Wang, Kevin; Ward, Thomas Z.; Gai, Zheng; Lee, Ho Nyung; Sefat, Athena S.; Lauter, Valeria; Liu, Zi-kui; Christen, Hans M.

    2015-11-05

    High-quality epitaxial growth of intermetallic MnPt films on oxides is achieved, with potential for multiferroic heterostructure applications. Antisite-stabilized spin-flipping induces ferromagnetism in MnPt films, although it is robustly antiferromagnetic in bulk. Thus, highly ordered antiferromagnetic MnPt films exhibit superiorly large exchange coupling with a ferromagnetic layer.

  6. Cationic disorder and Mn{sup 3+}/Mn{sup 4+} charge ordering in the B? and B? sites of Ca{sub 3}Mn{sub 2}NbO{sub 9} perovskite: a comparison with Ca{sub 3}Mn{sub 2}WO{sub 9}

    SciTech Connect (OSTI)

    Lpez, C.A.; Saleta, M.E.; Pedregosa, J.C.; Snchez, R.D.; Alonso, J.A.; and others

    2014-02-15

    We describe the preparation, crystal structure determination, magnetic and transport properties of two novel Mn-containing perovskites, with a different electronic configuration for Mn atoms located in B site. Ca{sub 3}Mn{sup 3+}{sub 2}WO{sub 9} and Ca{sub 3}Mn{sup 3+/4+}{sub 2}NbO{sub 9} were synthesized by standard ceramic procedures; the crystallographic structure was studied from X-ray powder diffraction (XRPD) and neutron powder diffraction (NPD). Both phases exhibit a monoclinic symmetry (S.G.: P2{sub 1}/n); Ca{sub 3}Mn{sub 2}WO{sub 9} presents a long-range ordering over the B sites, whereas Ca{sub 3}Mn{sub 2}NbO{sub 9} is strongly disordered. By in-situ NPD, the temperature evolution of the structure study presents an interesting evolution in the octahedral size (?MnO?) for Ca{sub 3}Mn{sub 2}NbO{sub 9}, driven by a charge ordering effect between Mn{sup 3+} and Mn{sup 4+} atoms, related to the anomaly observed in the transport measurements at T?160 K. Both materials present a magnetic order below T{sub C}=30 K and 40 K for W and Nb materials, respectively. The magneto-transport measurements display non-negligible magnetoresistance properties in the paramagnetic regime. - Graphical abstract: Comparison between the octahedron size and the magnetic behaviour for Ca{sub 3}Mn{sub 2}NbO{sub 9} in the temperature region where the charge and magnetic order occur. Display Omitted - Highlights: Two novel Mn-containing double perovskites were obtained by solid-state reactions. Both double perovskites are monoclinic (P2{sub 1}/n) determined by XRPD and NPD. Ca{sub 3}Mn{sub 2}WO{sub 9} contains Mn{sup 3+} while Ca{sub 3}Mn{sub 2}NbO{sub 9} includes mixed-valence cations Mn{sup 3+}/Mn{sup 4+}. Ca{sub 3}Mn{sub 2}NbO{sub 9} presents a charge-ordering effect between Mn{sup 3+} and Mn{sup 4+} evidenced by NPD. The magnetic and transport studies evidenced the charge ordering in Ca{sub 3}Mn{sub 2}NbO{sub 9}.

  7. Neutron scattering study of spin ordering and stripe pinning in superconducting La<mn>1.93mn>Sr>0.07mn>CuO>4mn>

    SciTech Connect (OSTI)

    Jacobsen, H.; Zaliznyak, I. A.; Savici, A. T.; Winn, B. L.; Chang, S.; Hücker, M.; Gu, G. D.; Tranquada, J. M.

    2015-11-20

    The relationships among charge order, spin fluctuations, and superconductivity in underdoped cuprates remain controversial. We use neutron scattering techniques to study these phenomena in La<mn>1.93mn>Sr>0.07mn>CuO>4mn> a superconductor with a transition temperature of Tc = 20 K. At T<< Tc, we find incommensurate spin fluctuations with a quasielastic energy spectrum and no sign of a gap within the energy range from 0.2 to 15 meV. A weak elastic magnetic component grows below ~ 10 K, consistent with results from local probes. Regarding the atomic lattice, we have discovered unexpectedly strong fluctuations of the CuO6 octahedra about Cu-O bonds, which are associated with inequivalent O sites within the CuO2 planes. Moreover, we observed a weak elastic (3 30) superlattice peak that implies a reduced lattice symmetry. The presence of inequivalent O sites rationalizes various pieces of evidence for charge stripe order in underdoped La2-xSrxCuO4. The coexistence of superconductivity with quasi-static spin-stripe order suggests the presence of intertwined orders; however, the rotation of the stripe orientation away from the Cu-O bonds might be connected with evidence for a finite gap at the nodal points of the superconducting gap function.

  8. Cell type-specific roles of Jak3 in IL-2-induced proliferative signal transduction

    SciTech Connect (OSTI)

    Fujii, Hodaka . E-mail: hodaka@med.nyu.edu

    2007-03-16

    Binding of interleukin-2 (IL-2) to its specific receptor induces activation of two members of Jak family protein tyrosine kinases, Jak1 and Jak3. An IL-2 receptor (IL-2R)-reconstituted NIH 3T3 fibroblast cell line proliferates in response to IL-2 only when hematopoietic lineage-specific Jak3 is ectopically expressed. However, the mechanism of Jak3-dependent proliferation in the fibroblast cell line is not known. Here, I showed that Jak3 expression is dispensable for IL-2-induced activation of Jak1 and Stat proteins and expression of nuclear proto-oncogenes in the IL-2R-reconstituted fibroblast cell line. Jak3 expression markedly enhanced these IL-2-induced signaling events. In contrast, Jak3 expression was essential for induction of cyclin genes involved in the G1-S transition. These data suggest a critical role of Jak3 in IL-2 signaling in the fibroblast cell line and may provide further insight into the cell type-specific mechanism of cytokine signaling.

  9. Clarification of enhanced ferromagnetism in Be-codoped InMnP fabricated using Mn/InP:Be bilayers grown by molecular beam epitaxy

    SciTech Connect (OSTI)

    Shon, Yoon; Lee, Sejoon; Taek Yoon, Im; Jeon, H. C.; Lee, D. J.; Kang, T. W.; Song, J. D.; Yoon, Chong S.; Kim, D. Y.; Park, C. S.

    2011-11-07

    The p-type InMnP:Be epilayers were prepared by the sequential growth of Mn/InP:Be bilayers using molecular-beam-epitaxy and the subsequent in-situ annealing at 200-300 deg. C. In triple-axis x-ray diffraction patterns, the samples revealed a shoulder peak indicative of intrinsic InMnP. The ferromagnetic transition in InMnP:Be was observed to occur at the elevated temperature of {approx}140 K, and the ferromagnetic spin-domains clearly appeared in magnetic force microscopy images. The improved ferromagnetic properties are attributed to the increased p-d hybridation due to high p-type conductivity of InMnP:Be (p {approx} 10{sup 20 }cm{sup -3}). The results suggest that enhanced ferromagnetism can be effectively obtained from Be-codoped InMnP.

  10. Magnetic properties of α−MnO{sub 2} and Co-doped α−MnO{sub 2} nanowires

    SciTech Connect (OSTI)

    Stella, C. Soundararajan, N. Ramachandran, K.

    2014-04-24

    α−MnO{sub 2} and Co-doped α−MnO{sub 2} nanowires (NWs) were synthesized by hydrothermal method. The structural characterization by XRD revealed the tetragonal structure of α−MnO{sub 2}. The formation of one dimensional (1D) NWs of pure and Co-doped α−MnO{sub 2} was confirmed from SEM. From UV-Vis absorption spectra, it is found that both pure and Co-doped α−MnO{sub 2} NWs showed blue shift compared to bulk, which revealed the quantum confinement in the synthesized samples. The magnetic properties were analyzed by VSM, which suggest that pure and doped α−MnO{sub 2} exhibit ferromagnetic behavior at room temperature (RT)

  11. Role of t{sub 2g} electrons in Mn-Tb coupling of multiferroic TbMnO{sub 3}

    SciTech Connect (OSTI)

    Guo, Y. Y.; Wang, Y. L.; Liu, J.-M.; Wei, T.

    2014-08-14

    We investigate the effect of Cr-doping in polycrystalline TbMn{sub 1?x}Cr{sub x}O{sub 3} (x???6%) ceramics on the magnetism, ferroelectricity, and dielectricity. The Cr substitution gradually suppresses the ferroelectricity induced by the Mn spiral spin ordering, and results in a stronger modulation of polarization by magnetic field with increasing x. However, the transition temperature T{sub Tb} corresponding to onset of Tb magnetic ordering has barely shifted with Cr doping. In other words, although the Cr-doping obviously disrupts the Mn spiral spin ordering, the exchange field J{sub Mn-Tb} acting on the Tb moments from the Mn-spin structure is hardly impacted. Our work demonstrates that the e{sub g} electron of Mn{sup 3+} plays an important role in forming the Mn spiral spin order, but the f-d exchange interaction between the Mn 3d spins and the Tb 4f moments in multiferroic TbMnO{sub 3} almost involves only the t{sub 2g} electrons.

  12. Effect of Mn substitution on the transport properties of co-sputtered Fe{sub 3−x}Mn{sub x}Si epilayers

    SciTech Connect (OSTI)

    Tang, M.; Jin, C.; Bai, H. L.

    2014-11-07

    Motivated by the theoretical calculations that Fe{sub 3−x}Mn{sub x}Si can simultaneously exhibit a high spin polarization with a high Curie temperature to be applied in spintronic devices, and in order to further study the effect of Mn contents on the physical properties of Fe{sub 3−x}Mn{sub x}Si, we have investigated the effect of Mn substitution on the transport properties of epitaxial Fe{sub 3−x}Mn{sub x}Si (0≤x≤1) films systematically. The Fe{sub 3−x}Mn{sub x}Si films were epitaxially grown on MgO(001) plane with 45° rotation. The magnetization for various x shows enhanced irreversibility, implying the antiferromagnetic ordering induced by the substitution of Mn. A metal-semiconductor crossover was observed due to the enhanced disorders of interactions and the local lowering of symmetry induced by the substitution of Mn. The single-domain state in the Fe{sub 3−x}Mn{sub x}Si films leads to twofold symmetric curves of the anisotropic magnetoresistance and planar Hall resistivity.

  13. Irreversible inhibition of RANK expression as a possible mechanism for IL-3 inhibition of RANKL-induced osteoclastogenesis

    SciTech Connect (OSTI)

    Khapli, Shruti M.; Tomar, Geetanjali B.; Barhanpurkar, Amruta P.; Gupta, Navita; Yogesha, S.D.; Pote, Satish T.; Wani, Mohan R.

    2010-09-03

    Research highlights: {yields} IL-3 inhibits receptor activator of NF-{kappa}B ligand (RANKL)-induced osteoclastogenesis. {yields} IL-3 inhibits RANKL-induced JNK activation. {yields} IL-3 down-regulates expression of c-Fos and NFATc1 transcription factors. {yields} IL-3 down-regulates RANK expression posttranscriptionally and irreversibly. {yields} IL-3 inhibits in vivo RANK expression. -- Abstract: IL-3, a cytokine secreted by activated T lymphocytes, stimulates the proliferation, differentiation and survival of pluripotent hematopoietic stem cells. In this study, we investigated the mechanism of inhibitory action of IL-3 on osteoclast differentiation. We show here that IL-3 significantly inhibits receptor activator of NF-{kappa}B (RANK) ligand (RANKL)-induced activation of c-Jun N-terminal kinase (JNK). IL-3 down-regulates expression of c-Fos and nuclear factor of activated T cells (NFATc1) transcription factors. In addition, IL-3 down-regulates RANK expression posttranscriptionally in both purified osteoclast precursors and whole bone marrow cells. Furthermore, the inhibitory effect of IL-3 on RANK expression was irreversible. Interestingly, IL-3 inhibits in vivo RANK expression in mice. Thus, we provide the first evidence that IL-3 irreversibly inhibits RANK expression that results in inhibition of important signaling molecules induced by RANKL.

  14. Plutonium Oxidation and Subsequent Reduction by Mn (IV) Minerals

    SciTech Connect (OSTI)

    KAPLAN, DANIEL

    2005-09-13

    Plutonium sorbed to rock tuff was preferentially associated with manganese oxides. On tuff and synthetic pyrolusite (Mn{sup IV}O{sub 2}), Pu(IV) or Pu(V) was initially oxidized, but over time Pu(IV) became the predominant oxidation state of sorbed Pu. Reduction of Pu(V/VI), even on non-oxidizing surfaces, is proposed to result from a lower Gibbs free energy of the hydrolyzed Pu(IV) surface species versus that of the Pu(V) or Pu(VI) surface species. This work suggests that despite initial oxidation of sorbed Pu by oxidizing surfaces to more soluble forms, the less mobile form of Pu, Pu(IV), will dominate Pu solid phase speciation during long term geologic storage. The safe design of a radioactive waste or spent nuclear fuel geologic repository requires a risk assessment of radionuclides that may potentially be released into the surrounding environment. Geochemical knowledge of the radionuclide and the surrounding environment is required for predicting subsurface fate and transport. Although difficult even in simple systems, this task grows increasingly complicated for constituents, like Pu, that exhibit complex environmental chemistries. The environmental behavior of Pu can be influenced by complexation, precipitation, adsorption, colloid formation, and oxidation/reduction (redox) reactions (1-3). To predict the environmental mobility of Pu, the most important of these factors is Pu oxidation state. This is because Pu(IV) is generally 2 to 3 orders of magnitude less mobile than Pu(V) in most environments (4). Further complicating matters, Pu commonly exists simultaneously in several oxidation states (5, 6). Choppin (7) reported Pu may exist as Pu(IV), Pu(V), or Pu(VI) oxic natural groundwaters. It is generally accepted that plutonium associated with suspended particulate matter is predominantly Pu(IV) (8-10), whereas Pu in the aqueous phase is predominantly Pu(V) (2, 11-13). The influence of the character of Mn-containing minerals expected to be found in subsurface

  15. Relation between the magnetization and the electrical properties of alloy GaSb-MnSb films

    SciTech Connect (OSTI)

    Koplak, O. V.; Polyakov, A. A.; Davydov, A. B.; Morgunov, R. B.; Talantsev, A. D.; Kochura, A. V.; Fedorchenko, I. V.; Novodvorskii, O. A.; Parshina, L. S.; Khramova, O. D.; Shorokhova, A. V.; Aronzon, B. A.

    2015-06-15

    The influence of the charge carrier concentration on the magnetic properties of GaSb-MnSb alloys is studied. The ferromagnetism of GaSb-MnSb films is caused by the presence of MnSb granules and manifests itself in both magnetometric measurements and the presence of an anisotropic magnetoresistance and the anomalous Hall effect. Electric conduction is executed by charge carriers (holes) in a GaSb matrix. The magnetization of clusters depends on stoichiometry and the concentration of Mn{sup 2+} and Mn{sup 3+} ions, which is specified by the film growth conditions. At high film growth temperatures, ferromagnetic clusters containing Mn{sup 2+} ions mainly form. At low growth temperatures, an antiferromagnetic phase containing Mn{sup 3+} ions forms.

  16. Effect of Composition and Heat Treatment on MnBi Magnetic Materials

    SciTech Connect (OSTI)

    Cui, Jun; Choi, Jung-Pyung; Polikarpov, Evgueni; Bowden, Mark E.; Xie, Wei; Li, Guosheng; Nie, Zimin; Zarkevich, Nikolai; Kramer, Matthew J.; Johnson, Duane D.

    2014-08-17

    The metallic compound MnBi is a promising rare-earth-free permanent magnet material. Compare to other rare-earth-free candidates, MnBi stands out for its high intrinsic coercivity (Hci) and its large positive temperature coefficient. Several groups have demonstrated that the Hci of MnBi compound in thin film or in powder form can exceed 12 kOe and 26 kOe at 300 K and 523 K, respectively. Such steep increase in Hci with increasing temperature is unique to MnBi. Consequently, MnBi is a highly sought-after hard phase for exchange coupling nanocomposite magnets. The reaction between Mn and Bi is peritectic, so Mn tends to precipitate out of the MnBi liquid during the solidification process. As result, the composition of the Mn-Bi alloy with the largest amount of the desired LTP (low temperature phase) MnBi and highest saturation magnetization will be over-stoichiometric and rich in Mn. The amount of additional Mn required to compensate the Mn precipitation depends on solidification rate: the faster the quench speed, the less Mn precipitates. Here we report a systematic study of the effect of composition and heat treatments on the phase contents and magnetic properties of Mn-Bi alloys. In this study, Mn-Bi alloys with 14 compositions were prepared using conventional metallurgical methods such as arc melting and vacuum heat treatment, and the obtained alloys were analyzed for compositions, crystal structures, phase content, and magnetic properties. The results show that the composition with 55 at.% Mn exhibits the highest LTP MnBi content and the highest magnetization. The sample with this composition shows >90 wt.% LTP MnBi content. Its measured saturation magnetization is 68 emu/g with 2.3 T applied field at 300 K; its coercivity is 13 kOe and its energy product is 12 MGOe at 300 K. A bulk magnet fabricated using this powder exhibits an energy product of 8.2 MGOe.

  17. Magnetostructural phase transformations in Tb 1-x Mn 2

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

    Zou, Junding; Paudyal, Durga; Liu, Jing; Mudryk, Yaroslav; Pecharsky, Vitalij K.; Gschneidner, Karl A.

    2015-01-16

    Magnetism and phase transformations in non-stoichiometric Tb1-xMn2 (x = 0.056, 0.039) have been studied as functions of temperature and magnetic field using magnetization, heat capacity, and X-ray powder diffraction measurements. Lowering the temperature, the compounds sequentially order ferrimagnetically and antiferromagnetically, and finally, exhibit spin reorientation transitions. Moreover, these structural distortions from room temperature cubic to low temperature rhombohedral structures occur at TN, and are accompanied by large volume changes reaching ~-1.27% and -1.42%, respectively. First principles electronic structure calculations confirm the phase transformation from the ferrimagnetic cubic structure to the antiferromagnetic rhombohedral structure in TbMn2.

  18. On the state of Mn impurity implanted in Si

    SciTech Connect (OSTI)

    Orlov, A. F.; Bublik, V. T.; Vdovin, V. I.; Agafonov, Yu. A.; Balagurov, L. A.; Zinenko, V. I.; Kulemanov, I. V.; Shcherbachev, K. D.

    2009-07-15

    The state of manganese impurity in implanted silicon at implantation doses of up to 5 x 10{sup 16} cm{sup -2} has been investigated by X-ray diffraction and transmission electron microscopy. It is established that, after short-term vacuum annealing at 850{sup o}C, most of the implanted manganese impurities are in microinclusions up to 20 nm in size formed by a tetragonal silicide phase of the Mn{sub 15}Si{sub 26} type.

  19. High-pressure structural study of MnF2

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

    Stavrou, Elissaios; Yao, Yansun; Goncharov, Alexander F.; Konopkova, Zuzana; Raptis, Constantine

    2015-02-01

    In this study, manganese fluoride (MnF2) with the tetragonal rutile-type structure has been studied using a synchrotron angle-dispersive powder x-ray diffraction and Raman spectroscopy in a diamond anvil cell up to 60 GPa at room temperature combined with first-principles density functional calculations. The experimental data reveal two pressure-induced structural phase transitions with the following sequence: rutile → SrI2 type (3 GPa)→ α–PbCl2 type (13 GPa). Complete structural information, including interatomic distances, has been determined in the case of MnF2 including the exact structure of the debated first high-pressure phase. First-principles density functional calculations confirm this phase transition sequence, and themore » two calculated transition pressures are in excellent agreement with the experiment. Lattice dynamics calculations also reproduce the experimental Raman spectra measured for the ambient and high-pressure phases. The results are discussed in line with the possible practical use of rutile-type fluorides in general and specifically MnF2 as a model compound to reveal the HP structural behavior of rutile-type SiO2 (Stishovite).« less

  20. Manganese valence and coordination structure in Mn,Mg-codoped {gamma}-AlON green phosphor

    SciTech Connect (OSTI)

    Takeda, Takashi; Xie, Rong-Jun; Hirosaki, Naoto; Matsushita, Yoshitaka; Honma, Tetuso

    2012-10-15

    The valence and coordination structure of manganese in a Mn,Mg-codoped {gamma}-AlON spinel-type oxynitride green phosphor were studied by synchrotron X-ray diffraction and absorption fine structure measurements. The absorption edge position of the XANES revealed the bivalency of Mn. Two cation sites are available in the spinel structure for cation doping: a tetrahedral site and an octahedral site. The pre-edge of the XANES and the distance to the nearest neighbor atoms obtained from the EXAFS measurement showed that Mn was situated at the tetrahedral site. Rietveld analysis showed that the vacancy occupied the octahedral site. The preferential occupation of the tetrahedral site by Mn and the roles of N and Mg are discussed in relation to the spinel crystal structure. - Graphical Abstract: Fourier transform of EXAFS of Mn K-edge for Mn,Mg-codoped green phosphor and Mn coordination structure. Highlights: Black-Right-Pointing-Pointer Mn, Mg-codoped {gamma}-AlON green phosphor for white LED. Black-Right-Pointing-Pointer The valence of Mn is divalent. Black-Right-Pointing-Pointer Mn occupies the tetrahedral site in the spinel structure.

  1. Ferromagnetic interactions and martensitic transformation in Fe doped Ni-Mn-In shape memory alloys

    SciTech Connect (OSTI)

    Lobo, D. N.; Priolkar, K. R.; Emura, S.; Nigam, A. K.

    2014-11-14

    The structure, magnetic, and martensitic properties of Fe doped Ni-Mn-In magnetic shape memory alloys have been studied by differential scanning calorimetry, magnetization, resistivity, X-ray diffraction (XRD), and EXAFS. While Ni{sub 2}MnIn{sub 1?x}Fe{sub x} (0???x???0.6) alloys are ferromagnetic and non martensitic, the martensitic transformation temperature in Ni{sub 2}Mn{sub 1.5}In{sub 1?y}Fe{sub y} and Ni{sub 2}Mn{sub 1.6}In{sub 1?y}Fe{sub y} increases for lower Fe concentrations (y???0.05) before decreasing sharply for higher Fe concentrations. XRD analysis reveals presence of cubic and tetragonal structural phases in Ni{sub 2}MnIn{sub 1?x}Fe{sub x} at room temperature with tetragonal phase content increasing with Fe doping. Even though the local structure around Mn and Ni in these Fe doped alloys is similar to martensitic Mn rich Ni-Mn-In alloys, presence of ferromagnetic interactions and structural disorder induced by Fe affect Mn-Ni-Mn antiferromagnetic interactions resulting in suppression of martensitic transformation in these Fe doped alloys.

  2. Effect of composition and heat treatment on MnBi magnetic materials

    SciTech Connect (OSTI)

    Cui, Jun [Pacific Northwest National Laboratory; Choi, Jung-Pyung [Pacific Northwest National Laboratory; Polikarpov, Evgueni [Pacific Northwest National Laboratory; Bowden, Mark E [Pacific Northwest National Laboratory; Xie, Wei [Pacific Northwest National Laboratory; Li, Guosheng [Pacific Northwest National Laboratory; Nie, Zimin [Pacific Northwest National Laboratory; Zarkevich, Nikolai [Ames Laboratory; Kramer, Matthew J [Ames Laboratory; Johnson, Duane [Ames Laboratory

    2014-10-01

    The metallic compound MnBi is a promising rare-earth-free permanent magnet material, unique among all candidates for its high intrinsic coercivity (Hci) and its large positive temperature coefficient. The Hci of MnBi in thin-film or powder form can exceed 12 and 26 kOe at 300 and 523 K, respectively. Such a steep rise in Hci with increasing temperature is unique to MnBi. Consequently, MnBi is a highly sought-after hard phase for exchange coupling nanocomposite magnets. However, the reaction between Mn and Bi is peritectic, and hence Mn tends to precipitate out of the MnBi liquid during the solidification process. As result, when the alloy is prepared using conventional induction or arc-melting casting methods, additional Mn is required to compensate the precipitation of Mn. In addition to composition, post-casting annealing plays an important role in obtaining a high content of MnBi low-temperature phase (LTP) because the annealing encourages the Mn precipitates and the unreacted Bi to react, forming the desired LTP phase. Here we report a systematic study of the effect of composition and heat treatments on the phase content and magnetic properties of MnBi alloys. In this study, 14 compositions were prepared using conventional metallurgical methods, and the compositions, crystal structures, phase content and magnetic properties of the resulting alloys were analyzed. The results show that the composition with 55 at.% Mn exhibits both the highest LTP content (93 wt.%) and magnetization (74 emu g?1 with 9 T applied field at 300 K).

  3. Dynamic study of (De)sodiation in alpha-MnO2 nanowires

    SciTech Connect (OSTI)

    Yuan, Yifei; Ma, Lu; He, Kun; Yao, Wentao; Nie, Anmin; Bi, Xuanxuan; Amine, Khalil; Wu, Tianpin; Lu, Jun; Shahbazian-Yassr, Reza

    2016-01-01

    In this report, the electrochemical sodiation and desodiation in single crystalline alpha-MnO2 nanowires are studied dynamically at both single particle level using in situ transmission electron microscopy (TEM) and bulk level using in situ synchrotron X-ray. The TEM results suggest that the first sodiation process starts with tunnel-based Na+ intercalation, experiences the formation of Na0.5MnO2 as a result of tunnel degradation, and ends with the Mn2O3 phase. The inserted Na+ can be partially extracted out of the sodiated products, and the following cycles are dominated by the reversible conversion reaction between Na0.5MnO2 and Mn2O3. The Mn valence evolution inside a cycling coin using alpha-MnO2 nanowire electrode also exhibits partially reversible characteristic, agreeing well with the in situ TEM analysis. The sodiation is compared with lithiation in the same alpha-MnO2 nanowires. Both Na+ and Li+ interact with the tunneled structure via a similar tunnel -driven intercalation mechanism before Mn4+ is reduced to Mn3.5+. For the following deep insertion, the tunnels survive up. to LiMnO2 (Mn3+) during lithiation, while the sodiation proceeds via a different mechanism that involves obvious phase transition and fast tunnel degradation after Mn's valence is below 3.5+. The difference in charge carrier insertion mechanisms can be ascribed to the strong interaction between the tunnel frame and inserted Na+ possessing a larger ionic size than inserted Li+.

  4. Large exchange bias enhancement in (Pt(or Pd)/Co)/IrMn/Co trilayers with ultrathin IrMn thanks to interfacial Cu dusting

    SciTech Connect (OSTI)

    Vinai, G. [SPINTEC, UMR 8191 CEA/CNRS/UJF/Grenoble-INP, CEA/INAC, 17, rue des Martyrs, 38054 Grenoble (France); Crocus Technology, 4 Place Robert Schuman, 38054 Grenoble (France); Moritz, J. [Institut Jean Lamour, UMR 7198 CNRS - Universit de Lorraine, Bd des Aiguillettes, BP 70239, F-54506 Vandoeuvre-les-Nancy Cedex (France); Bandiera, S. [Crocus Technology, 4 Place Robert Schuman, 38054 Grenoble (France); Prejbeanu, I. L.; Dieny, B. [SPINTEC, UMR 8191 CEA/CNRS/UJF/Grenoble-INP, CEA/INAC, 17, rue des Martyrs, 38054 Grenoble (France)

    2014-04-21

    The magnitude of exchange bias (H{sub ex}) at room temperature can be significantly enhanced in IrMn/Co and (Pt(or Pd)/Co)/IrMn/Co structures thanks to the insertion of an ultrathin Cu dusting layer at the IrMn/Co interface. The combination of trilayer structure and interfacial Cu dusting leads to a three-fold increase in H{sub ex} as compared to the conventional IrMn/Co bilayer structure, with an increased blocking temperature (T{sub B}) and a concave curvature of the temperature dependence H{sub ex}(T), ideal for improved Thermally Assisted-Magnetic Random Access Memory storage layer. This exchange bias enhancement is ascribed to a reduction of the spin frustration at the IrMn/Co interface thanks to interfacial Cu addition.

  5. File:USDA-CE-Production-GIFmaps-IL.pdf | Open Energy Information

    Open Energy Info (EERE)

    IL.pdf Jump to: navigation, search File File history File usage Illinois Ethanol Plant Locations Size of this preview: 463 599 pixels. Other resolution: 464 600 pixels. Full...

  6. DOE - Office of Legacy Management -- Hydroblast Corp - IL 0-03

    Office of Legacy Management (LM)

    FUSRAP Also see Documents Related to HYDROBLAST CORP. IL.0-03-1 - AEC Memorandum; Smith to Malone; Subject: Shipment of Bethlehem Rods, Reference NYC-504; June 22, 1951 ...

  7. Synthesis, characterization and electrochemical performance of Al-substituted Li₂MnO₃

    SciTech Connect (OSTI)

    Dhital, Chetan; Huq, Ashfia; Paranthaman, Mariappan Parans; Manivannan, Ayyakkannu; Torres-Castro, Loraine; Shojan, Jifi; Julien, Christian M.; Katiyar, Ram S.

    2015-08-08

    Li2MnO3 is known to be electrochemically inactive due to Mn in tetravalent oxidation state. Several compositions such as Li2MnO3 , Li1.5Al0.17MnO3, Li1.0Al0.33MnO3 and Li0.5Al0.5MnO3 were synthesized by a sol–gel Pechini method. All the samples were characterized with x-ray diffraction, Raman, x-ray photoelectron spectroscopy, scanning electron microscopy, Tap density and BET analyzer. X-ray diffraction patterns indicated the presence of monoclinic phase for pristine Li2MnO3and mixed monoclinic/spinel phases (Li2 - xMn1 - yAlx + yO3 + z) for Al-substituted Li2MnO3compounds. The Al substitution seems to occur both at Li and Mn sites, which could explain the presence of spinel phase. X-ray photoelectron spectroscopy for Mn 2p orbital reveals a significant decrease in binding energy for Li1.0Al0.33MnO3 and Li0.5Al0.5MnO3 compounds. Cyclic voltammetry, charge/discharge cycles and electrochemical impedance spectroscopy were also performed. A discharge capacity of 24 mAh g-1 for Li2MnO3, 68 mAh g-1 for Li1.5Al0.17MnO3, 58 mAh g-1 for Li1.0Al0.33MnO3 and 74 mAh g-1 for Li0.5Al0.5MnO3 were obtained. As a result, aluminum substitutions increased the formation of spinel phase which is responsible for cycling.

  8. The magnetic origin of multiferroic Y{sub 2}CoMnO{sub 6}

    SciTech Connect (OSTI)

    Jia, Ting; Zeng, Zhi; Li, X. G.; Lin, H. Q.

    2015-05-07

    It has been found experimentally that the ferroelectricity in Y{sub 2}CoMnO{sub 6} is driven by a magnetic ordering of collinear up-up-down-down (↑↑↓↓). Here, the origin of the magnetism and thereby ferroelectricity is studied using first-principles calculations. We first confirm that the experimentally observed ↑↑↓↓ antiferromagnetic structure is the ground state of Y{sub 2}CoMnO{sub 6}. Additionally, both the Co{sup 2+} and Mn{sup 4+} are in the high-spin state. By analyzing the exchange coupling and corresponding pathways, we conclude that the ↑↑↓↓ spin order in Y{sub 2}CoMnO{sub 6} originates from a subtle competition between the ferromagnetic Co-O-Mn super-exchange and antiferromagnetic Co-Mn direct-exchange along c axis.

  9. Structural and ferromagnetic properties of an orthorhombic phase of MnBi stabilized with Rh additions

    SciTech Connect (OSTI)

    Taufour, Valentin; Thimmaiah, Srinivasa; March, Stephen; Saunders, Scott; Sun, Kewei; Lamichhane, Tej Nath; Kramer, Matthew J.; Bud’ko, Sergey L.; Canfield, Paul C.

    2015-07-28

    The article addresses the possibility of alloy elements in MnBi which may modify the thermodynamic stability of the NiAs-type structure without significantly degrading the magnetic properties. The addition of small amounts of Rh and Mn provides an improvement in the thermal stability with some degradation of the magnetic properties. The small amounts of Rh and Mn additions in MnBi stabilize an orthorhombic phase whose structural and magnetic properties are closely related to the ones of the previously reported high-temperature phase of MnBi (HT MnBi). The properties of the HT MnBi, which is stable between 613 and 719 K, have not been studied in detail because of its transformation to the stable low-temperature MnBi (LT MnBi), making measurements near and below its Curie temperature difficult. The Rh-stabilized MnBi with chemical formula Mn1.0625–xRhxBi [x=0.02(1)] adopts a new superstructure of the NiAs/Ni2In structure family. It is ferromagnetic below a Curie temperature of 416 K. The critical exponents of the ferromagnetic transition are not of the mean-field type but are closer to those associated with the Ising model in three dimensions. The magnetic anisotropy is uniaxial; the anisotropy energy is rather large, and it does not increase when raising the temperature, contrary to what happens in LT MnBi. The saturation magnetization is approximately 3μB/f.u. at low temperatures. Thus, while this exact composition may not be application ready, it does show that alloying is a viable route to modifying the stability of this class of rare-earth-free magnet alloys.

  10. Cr(OH)₃(s) Oxidation Induced by Surface Catalyzed Mn(II) Oxidation

    SciTech Connect (OSTI)

    Namgung, Seonyi; Kwon, M.; Qafoku, Nikolla; Lee, Gie Hyeon

    2014-09-16

    This study examined the feasibility of Cr(OH)₃(s) oxidation mediated by surface catalyzed Mn(II) oxidation under common groundwater pH conditions as a potential pathway of natural Cr(VI) contaminations. Dissolved Mn(II) (50 μM) was reacted with or without synthesized Cr(OH)₃(s) (1.0 g/L) at pH 7 – 9 under oxic or anoxic conditions. In the absence of Cr(OH)₃(s), homogeneous Mn(II) oxidation by dissolved O₂ was not observed at pH ≤ 8.0 for 50 d. At pH 9.0, by contrast, dissolved Mn(II) was completely removed within 8 d and precipitated as hausmannite. When Cr(OH)₃(s) was present, this solid was oxidized and released substantial amounts of Cr(VI) as dissolved Mn(II) was added into the suspension at pH ≥ 8.0 under oxic conditions. Our results suggest that Cr(OH)₃(s) was readily oxidized by a newly formed Mn oxide as a result of Mn(II) oxidation catalyzed on Cr(OH)₃(s) surface. XANES analysis of the residual solids after the reaction between 1.0 g/L Cr(OH)₃(s) and 204 μM Mn(II) at pH 9.0 for 22 d revealed that the product of surface catalyzed Mn(II) oxidation resembled birnessite. The rate and extent of Cr(OH)₃(s) oxidation was likely controlled by those of surface catalyzed Mn(II) oxidation as the production of Cr(VI) increased with increasing pH and initial Mn(II) concentrations. This study evokes the potential environmental hazard of sparingly soluble Cr(OH)₃(s) that can be a source of Cr(VI) in the presence of dissolved Mn(II).

  11. Structural and ferromagnetic properties of an orthorhombic phase of MnBi stabilized with Rh additions

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

    Taufour, Valentin; Thimmaiah, Srinivasa; March, Stephen; Saunders, Scott; Sun, Kewei; Lamichhane, Tej Nath; Kramer, Matthew J.; Bud’ko, Sergey L.; Canfield, Paul C.

    2015-07-28

    The article addresses the possibility of alloy elements in MnBi which may modify the thermodynamic stability of the NiAs-type structure without significantly degrading the magnetic properties. The addition of small amounts of Rh and Mn provides an improvement in the thermal stability with some degradation of the magnetic properties. The small amounts of Rh and Mn additions in MnBi stabilize an orthorhombic phase whose structural and magnetic properties are closely related to the ones of the previously reported high-temperature phase of MnBi (HT MnBi). The properties of the HT MnBi, which is stable between 613 and 719 K, have notmore » been studied in detail because of its transformation to the stable low-temperature MnBi (LT MnBi), making measurements near and below its Curie temperature difficult. The Rh-stabilized MnBi with chemical formula Mn1.0625–xRhxBi [x=0.02(1)] adopts a new superstructure of the NiAs/Ni2In structure family. It is ferromagnetic below a Curie temperature of 416 K. The critical exponents of the ferromagnetic transition are not of the mean-field type but are closer to those associated with the Ising model in three dimensions. The magnetic anisotropy is uniaxial; the anisotropy energy is rather large, and it does not increase when raising the temperature, contrary to what happens in LT MnBi. The saturation magnetization is approximately 3μB/f.u. at low temperatures. Thus, while this exact composition may not be application ready, it does show that alloying is a viable route to modifying the stability of this class of rare-earth-free magnet alloys.« less

  12. Electronic Structure and Oxidation State Changes in the Mn (4) Ca Cluster of Photosystem II

    SciTech Connect (OSTI)

    Yano, J.; Pushkar, Y.; Messinger, J.; Bergmann, U.; Glatzel, P.; Yachandra, V.K.; /SLAC

    2012-08-17

    Oxygen-evolving complex (Mn{sub 4}Ca cluster) of Photosystem II cycles through five intermediate states (S{sub i}-states, i = 0-4) before a molecule of dioxygen is released. During the S-state transitions, electrons are extracted from the OEC, either from Mn or alternatively from a Mn ligand. The oxidation state of Mn is widely accepted as Mn{sub 4}(III{sub 2},IV{sub 2}) and Mn{sub 4}(III,IV{sub 3}) for S{sub 1} and S{sub 2} states, while it is still controversial for the S{sub 0} and S{sub 3} states. We used resonant inelastic X-ray scattering (RIXS) to study the electronic structure of Mn{sub 4}Ca complex in the OEC. The RIXS data yield two-dimensional plots that provide a significant advantage by obtaining both K-edge pre-edge and L-edge-like spectra (metal spin state) simultaneously. We have collected data from PSII samples in the each of the S-states and compared them with data from various inorganic Mn complexes. The spectral changes in the Mn 1s2p{sub 3/2} RIXS spectra between the S-states were compared to those of the oxides of Mn and coordination complexes. The results indicate strong covalency for the electronic configuration in the OEC, and we conclude that the electron is transferred from a strongly delocalized orbital, compared to those in Mn oxides or coordination complexes. The magnitude for the S{sub 0} to S{sub 1}, and S{sub 1} to S{sub 2} transitions is twice as large as that during the S{sub 2} to S{sub 3} transition, indicating that the electron for this transition is extracted from a highly delocalized orbital with little change in charge density at the Mn atoms.

  13. IL-33 inhibits RANKL-induced osteoclast formation through the regulation of Blimp-1 and IRF-8 expression

    SciTech Connect (OSTI)

    Kiyomiya, Hiroyasu; Ariyoshi, Wataru; Okinaga, Toshinori; Kaneuji, Takeshi; Mitsugi, Sho; Sakurai, Takuma; Habu, Manabu; Yoshioka, Izumi; Tominaga, Kazuhiro; and others

    2015-05-01

    Interleukin (IL)-33 is a recently discovered proinflammatory cytokine that belongs to the IL-1 family. Several studies have reported that IL-33 inhibits osteoclast differentiation. However, the mechanism of IL-33 regulation of osteoclastogenesis remains unclear. In the present study, we examined the effect of IL-33 on osteoclast formation in vitro. IL-33 suppressed osteoclast formation in both mouse bone marrow cells and monocyte/macrophage cell line RAW264.7 cells induced by receptor activator of NF-κB ligand (RANKL) and/or macrophage stimulating factor (M-CSF). IL-33 also inhibited the expression of RANKL-induced nuclear factor of activated T-cell cytoplasmic 1 (NFATc1), thereby decreasing the expression of osteoclastogenesis-related marker genes, including Cathepsin K, Osteoclast stimulatory transmembrane protein (Oc-stamp) and Tartrate-resistant acid phosphatase (Trap). Blockage of IL-33-ST2 binding suppressed the IL-33-mediated inhibition of NFATc1. RANKL-induced B-lymphocyte-induced maturation protein-1 (Blimp-1) expression was also suppressed by IL-33, which was followed by the stimulation of anti-osteoclastic genes such as interferon regulatory factor-8 (IRF-8). These results suggest that IL-33-ST2 interactions down-regulate both RANKL-induced NFATc1 activation and osteoclast differentiation via the regulation of Blimp-1 and IRF-8 expression. - Highlights: • IL-33 inhibits RANKL-induced osteoclast formation. • IL-33 has inhibitory effect on the RANKL-induced NFATc1 expression. • IL-33-induced NFATc1 suppression depends on the regulation of Blimp-1 and IRF-8.

  14. Cosmological constraints from measurements of type Ia supernovae discovered during the first 1.5 yr of the Pan-STARRS1 survey

    SciTech Connect (OSTI)

    Rest, A. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Scolnic, D.; Riess, A.; Rodney, S.; Brout, D. [Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States); Foley, R. J.; Chornock, R.; Berger, E.; Soderberg, A. M.; Stubbs, C. W.; Kirshner, R. P.; Challis, P.; Czekala, I.; Drout, M. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Huber, M. E.; Tonry, J. L. [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Narayan, G. [Department of Physics, Harvard University, 17 Oxford Street, Cambridge, MA 02138 (United States); Smartt, S. J. [Astrophysics Research Centre, School of Mathematics and Physics, Queens University Belfast, Belfast BT71NN (United Kingdom); Schlafly, E. [Max Planck Institute for Astronomy, Knigstuhl 17, D-69117 Heidelberg (Germany); Botticella, M. T. [INAF-Osservatorio Astronomico di Capodimonte, Salita Moiariello 16, I-80131 Napoli (Italy); and others

    2014-11-01

    We present griz {sub P1} light curves of 146 spectroscopically confirmed Type Ia supernovae (SNe Ia; 0.03 < z < 0.65) discovered during the first 1.5 yr of the Pan-STARRS1 Medium Deep Survey. The Pan-STARRS1 natural photometric system is determined by a combination of on-site measurements of the instrument response function and observations of spectrophotometric standard stars. We find that the systematic uncertainties in the photometric system are currently 1.2% without accounting for the uncertainty in the Hubble Space Telescope Calspec definition of the AB system. A Hubble diagram is constructed with a subset of 113 out of 146 SNe Ia that pass our light curve quality cuts. The cosmological fit to 310 SNe Ia (113 PS1 SNe Ia + 222 light curves from 197 low-z SNe Ia), using only supernovae (SNe) and assuming a constant dark energy equation of state and flatness, yields w=?1.120{sub ?0.206}{sup +0.360}(Stat){sub ?0.291}{sup +0.269}(Sys). When combined with BAO+CMB(Planck)+H {sub 0}, the analysis yields ?{sub M}=0.280{sub ?0.012}{sup +0.013} and w=?1.166{sub ?0.069}{sup +0.072} including all identified systematics. The value of w is inconsistent with the cosmological constant value of 1 at the 2.3? level. Tension endures after removing either the baryon acoustic oscillation (BAO) or the H {sub 0} constraint, though it is strongest when including the H {sub 0} constraint. If we include WMAP9 cosmic microwave background (CMB) constraints instead of those from Planck, we find w=?1.124{sub ?0.065}{sup +0.083}, which diminishes the discord to <2?. We cannot conclude whether the tension with flat ?CDM is a feature of dark energy, new physics, or a combination of chance and systematic errors. The full Pan-STARRS1 SN sample with ?three times as many SNe should provide more conclusive results.

  15. Preparation and electrochemical properties of lamellar MnO{sub 2} for supercapacitors

    SciTech Connect (OSTI)

    Yan, Jun; Wei, Tong; Cheng, Jie; Fan, Zhuangjun; Zhang, Milin

    2010-02-15

    Lamellar birnessite-type MnO{sub 2} materials were prepared by changing the pH of the initial reaction system via hydrothermal synthesis. The interlayer spacing of MnO{sub 2} with a layered structure increased gradually when the initial pH value varied from 12.43 to 2.81, while the MnO{sub 2}, composed of {alpha}-MnO{sub 2} and {gamma}-MnO{sub 2}, had a rod-like structure at pH 0.63. Electrochemical studies indicated that the specific capacitance of birnessite-type MnO{sub 2} was much higher than that of rod-like MnO{sub 2} at high discharge current densities due to the lamellar structure with fast intercalation/deintercalation of protons and high utilization of MnO{sub 2}. The initial specific capacitance of MnO{sub 2} prepared at pH 2.81 was 242.1 F g{sup -1} at 2 mA cm{sup -2} in 2 mol L{sup -1} (NH{sub 4}){sub 2}SO{sub 4} aqueous electrolyte. The capacitance increased by about 8.1% of initial capacitance after 200 cycles at a current density of 100 mA cm{sup -2}.

  16. In operando X-ray studies of the conversion reaction in Mn3O4...

    Office of Scientific and Technical Information (OSTI)

    of the conversion reaction in Mn3O4 lithium battery anodes Citation Details ... energy storage (including batteries and capacitors), hydrogen and fuel ...

  17. Phase stability of the SrMnO[subscript 3] hexagonal perovskite...

    Office of Scientific and Technical Information (OSTI)

    SrMnOsubscript 3 hexagonal perovskite system at high pressure and temperature Citation ... Country of Publication: United States Language: ENGLISH Word Cloud More Like This Full ...

  18. International Falls, MN Natural Gas Pipeline Imports From Canada (Dollars

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

    per Thousand Cubic Feet) Dollars per Thousand Cubic Feet) International Falls, MN Natural Gas Pipeline Imports From Canada (Dollars per Thousand Cubic Feet) Decade Year-0 Year-1 Year-2 Year-3 Year-4 Year-5 Year-6 Year-7 Year-8 Year-9 1990's 1.71 2.03 2.00 2.33 2000's 2.77 4.85 3.01 -- -- 11.20 -- - = No Data Reported; -- = Not Applicable; NA = Not Available; W = Withheld to avoid disclosure of individual company data. Release Date: 08/31/2016 Next Release Date: 09/30/2016 Referring Pages:

  19. International Falls, MN Natural Gas Pipeline Imports From Canada (Million

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

    Cubic Feet) Million Cubic Feet) International Falls, MN Natural Gas Pipeline Imports From Canada (Million Cubic Feet) Decade Year-0 Year-1 Year-2 Year-3 Year-4 Year-5 Year-6 Year-7 Year-8 Year-9 1990's 6,373 6,544 6,103 4,857 2000's 3,022 617 602 0 0 22 0 - = No Data Reported; -- = Not Applicable; NA = Not Available; W = Withheld to avoid disclosure of individual company data. Release Date: 08/31/2016 Next Release Date: 09/30/2016 Referring Pages: U.S.

  20. Electrochemical performance studies of MnO{sub 2} nanoflowers recovered from spent battery

    SciTech Connect (OSTI)

    Ali, Gomaa A.M.; Tan, Ling Ling; Jose, Rajan; Yusoff, Mashitah M.; Chong, Kwok Feng

    2014-12-15

    Highlights: MnO{sub 2} is recovered from spent zinccarbon batteries as nanoflowers structure. Recovered MnO{sub 2} nanoflowers show high specific capacitance. Recovered MnO{sub 2} nanoflowers show stable electrochemical cycling up to 900 cycles. Recovered MnO{sub 2} nanoflowers show low resistance in EIS data. - Abstract: The electrochemical performance of MnO{sub 2} nanoflowers recovered from spent household zinccarbon battery is studied by cyclic voltammetry, galvanostatic charge/discharge cycling and electrochemical impedance spectroscopy. MnO{sub 2} nanoflowers are recovered from spent zinccarbon battery by combination of solution leaching and electrowinning techniques. In an effort to utilize recovered MnO{sub 2} nanoflowers as energy storage supercapacitor, it is crucial to understand their structure and electrochemical performance. X-ray diffraction analysis confirms the recovery of MnO{sub 2} in birnessite phase, while electron microscopy analysis shows the MnO{sub 2} is recovered as 3D nanostructure with nanoflower morphology. The recovered MnO{sub 2} nanoflowers exhibit high specific capacitance (294 F g{sup ?1} at 10 mV s{sup ?1}; 208.5 F g{sup ?1} at 0.1 A g{sup ?1}) in 1 M Na{sub 2}SO{sub 4} electrolyte, with stable electrochemical cycling. Electrochemical data analysis reveal the great potential of MnO{sub 2} nanoflowers recovered from spent zinccarbon battery in the development of high performance energy storage supercapacitor system.

  1. No X-rays from the very nearby type Ia SN 2014J: Constraints on its environment

    SciTech Connect (OSTI)

    Margutti, R.; Parrent, J.; Kamble, A.; Soderberg, A. M.; Milisavljevic, D.; Drout, M. R.; Kirshner, R. [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States); Foley, R. J. [Astronomy Department, University of Illinois at Urbana-Champaign, 1002 W. Green Street, Urbana, IL 61801 (United States)

    2014-07-20

    Deep X-ray observations of the post-explosion environment around the very nearby Type Ia SN 2014J (d{sub L} = 3.5 Mpc) reveal no X-ray emission down to a luminosity L{sub x} < 7 10{sup 36} erg s{sup 1} (0.3-10 keV) at ?t ? 20 days after the explosion. We interpret this limit in the context of inverse Compton emission from upscattered optical photons by the supernova shock and constrain the pre-explosion mass-loss rate of the stellar progenitor system to be M-dot <10{sup ?9} M{sub ?} yr{sup ?1} (for wind velocity v{sub w} = 100 km s{sup 1}). Alternatively, the SN shock might be expanding into a uniform medium with density n{sub CSM} < 3 cm{sup 3}. These results rule out single-degenerate (SD) systems with steady mass loss until the terminal explosion and constrain the fraction of transferred material lost at the outer Lagrangian point to be ?1%. The allowed progenitors are (1) white dwarf-white dwarf progenitors, (2) SD systems with unstable hydrogen burning experiencing recurrent nova eruptions with recurrence time t < 300 yr, and (3) stars where the mass loss ceases before the explosion.

  2. ASYMMETRY IN THE OBSERVED METAL-RICH EJECTA OF THE GALACTIC TYPE IA SUPERNOVA REMNANT G299.22.9

    SciTech Connect (OSTI)

    Post, Seth; Park, Sangwook [Department of Physics, University of Texas at Arlington, Arlington, Box 19059, TX 76019 (United States); Badenes, Carles [Department of Physics and Astronomy and Pittsburgh Particle Physics, Astrophysics, and Cosmology Center (PITT-PACC), University of Pittsburgh, 3941 OHara Street, Pittsburgh, PA 15260 (United States); Burrows, David N. [Department of Astronomy and Astrophysics, Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802 (United States); Hughes, John P. [Department of Physics and Astronomy, Rutgers University, 136 Frelinghuysen Road, Piscataway, NJ 08854-8019 (United States); Lee, Jae-Joon [Korea Astronomy and Space Science Institute, Daejeon 305-348 (Korea, Republic of); Mori, Koji [Department of Applied Physics, University of Miyazaki, 1-1 Gakuen Kibana-dai Nishi, Miyazaki 889-2192 (Japan); Slane, Patrick O., E-mail: seth.post@mavs.uta.edu, E-mail: badenes@pitt.edu, E-mail: burrows@astro.psu.edu, E-mail: jph@physics.rutgers.edu, E-mail: mori@astro.miyazaki-u.ac.jp, E-mail: slane@cfa.harvard.edu [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

    2014-09-01

    We have performed a deep Chandra observation of the Galactic TypeIa supernova remnant G299.22.9. Here we report the initial results from our imaging and spectral analysis. The observed abundance ratios of the central ejecta are in good agreement with those predicted by delayed-detonation TypeIa supernovae models. We reveal inhomogeneous spatial and spectral structures of metal-rich ejecta in G299.22.9. The Fe/Si abundance ratio in the northern part of the central ejecta region is higher than that in the southern part. A significant continuous elongation of ejecta material extends out to the western outermost boundary of the remnant. In this western elongation, both the Si and Fe are enriched with a similar abundance ratio to that in the southern part of the central ejecta region. These structured distributions of metal-rich ejecta material suggest that this TypeIa supernova might have undergone a significantly asymmetric explosion and/or has been expanding into a structured medium.

  3. Lattice Mn3+ Behaviors in Li4Ti5O12/LiNi0.5Mn1.5O4 Full Cells

    SciTech Connect (OSTI)

    Zheng, Jianming; Xiao, Jie; Nie, Zimin; Zhang, Jiguang

    2013-05-28

    High voltage spinels LiNi0.5Mn1.5O4 (LNMO) with different contents of residual Mn3+ ions have been evaluated in full cells using Li4Ti5O12 (LTO) as standard anode. Greatly improved cycling stability has been observed for all spinels in LTO-limited full cell, compared with those in LNMO-limited ones, while the underlying mechanisms are quite different. It has been discovered that the participation of active Mn3+ in the extended cycling and thus its observable contribution to Li+ diffusion kinetics depend on the limiting electrode and the sufficiency of Li+ ions. Potential Mn dissolution has also been discussed to identify the key factors that need to be considered to construct full cells employing high voltage spinel as the cathode.

  4. Magnetic and structural properties of Zn doped MnV{sub 2}O{sub 4}

    SciTech Connect (OSTI)

    Shahi, Prashant; Shukla, K. K.; Singh, Rahul; Chatterjee, Sandip; Das, A.; Ghosh, A. K.; Nigam, A. K.

    2014-04-24

    The magnetization, Neutron diffraction and X-ray diffraction of Zn doped MnV{sub 2}O{sub 4} as a function of temperature have been measured. It has been observed, with increase of Zn the non-linear orientation of Mn spins with the V spins will decrease which effectively decrease the structural transition temperature more rapidly than Curie Temperature.

  5. Spin correlations and electron transport in MnBi:Au films

    SciTech Connect (OSTI)

    Kharel, P.; Skomski, R.; Sellmyer, D. J.

    2011-04-01

    The structural, magnetic, and electron transport properties of Mn{sub 55-x}Au{sub x}Bi{sub 45} (x = 0, 4.5) thin films prepared by magnetron sputtering have been investigated. The magnetization of the MnBi films decreases and the coercivity increases due to Au doping. The temperature dependence of resistivity between 2 to 300 K shows that the films are metallic but the 4.5% Au-doped film shows a Kondo behavior with resistance minimum at 10.2 K. The magnetoresistance is anisotropic and the positive transverse magnetoresistance is significantly enhanced (16.3% at 70 kOe) by Au doping. We interpret these data in terms of a model in which Au atoms preferentially substitute for Mn atoms on the Mn lattice, and some Mn atoms are displaced to interstitial sites in the NiAs structure. These interstitial Mn atoms are coupled antiferromagnetically to the Mn atoms on the original Mn lattice leading to the large decrease in magnetization, Kondo effect, and the positive magnetoresistance.

  6. Room temperature spin-polarizations of Mn-based antiferromagnetic nanoelectrodes

    SciTech Connect (OSTI)

    Yamada, Toyo Kazu; Vazquez de Parga, Amadeo L.

    2014-11-03

    Antiferromagnets produce no stray field, and therefore, a tip electrode made of antiferromagnetic material has been considered to be the most suitable choice to measure such as magnetoresistance (MR) through single isolated magnetic nanoparticles, molecules, and ultrathin films. Spin polarizations (P) of antiferromagnetic 3-nm, 6-nm, and annealed 3-nm Mn films grown on W tips with a bcc(110) apex as well as bulk-NiMn tips were obtained at 300?K by measuring MR in ultrahigh vacuum by means of spin-polarized scanning tunneling microscopy using a layerwise antiferromagnetically stacking bct-Mn(001) film electrode. The Mn-coated tips with coverages of 3 and 6?nm exhibited P values of 1??1% and 3??2%, respectively, which tips likely contain ?- or strained Mn. With a thermal assist, the crystalline quality and the magnetic stability of the film could increase. The annealed tip exhibited P?=?9??2%. The bulk-NiMn tips exhibit spin polarizations of 0 or 6??2% probably depending on the chemical species (Mn or Ni) present at the apex of the tip. Fe-coated W tips were used to estimate the bct-Mn(001) film spin polarization.

  7. Site Determination and Magnetism of Mn Doping in Protein Encapsulated Iron Oxide Nanoparticles

    SciTech Connect (OSTI)

    Pool, V.; Klem, M.; Jolley, J.; Arenholz, E.A.; Douglas, T.; Young, M.; Idzerda, Y.U.

    2010-01-11

    Soft-X-ray absorption spectroscopy, soft-X-ray magnetic circular dichroism, and alternating current magnetic susceptibility were performed on 6.7 nm iron oxide nanoparticles doped with (5-33%) Mn grown inside the horse-spleen ferritin protein cages and compared to similarly protein encapsulated pure Fe-oxide and Mn-oxide nanoparticles to determine the site of the Mn dopant and to quantify the magnetic behavior with varying Mn concentration. The Mn dopant is shown to substitute preferentially as Mn{sup +2} and prefers the octahedral site in the defected spinel structure. The Mn multiplet structure for the nanoparticles is simpler than for the bulk standards, suggesting that the nanoparticle lattices are relaxed from the distortions present in the bulk. Addition of Mn is found to alter the host Fe-oxide lattice from a defected ferrimagnetic spinel structure similar to {gamma}-Fe{sub 2}O{sub 3} to an non-ferromagnetic spinel structure with a local Fe environment similar to Fe{sub 3}O{sub 4}.

  8. Impedance studies of the thin film LiMn2O4/electrolyteinterface

    SciTech Connect (OSTI)

    Striebel, Kathryn A.; Sakai, E.; Cairns, Elton J.

    2001-04-07

    Room-temperature impedance measurements of a thin-film LiMn2O4/LiPF6-EC-DMC interface have been used to identify the spontaneous formation Li2Mn2O4 at the interface at room temperature at voltages of 3.7 and higher. The impedance of the LiMn2O4 films exhibited two time constants: at about 14 kHz and 60 to 200 Hz. The high frequency loop is dependent on film morphology and was attributed to the substrate/oxide interface. The low frequency behavior was dependent on both state-of-charge (SOC) and time at a given SOC. At full charge the impedance in this electrolyte was stable at room temperature over several days. At high lithium contents, film OCV and impedance tended to grow logarithmically with time, with lower rates for lower Mn3+ content in the film. The increased impedance was removed by oxidation of the film to 4.5V vs. Li/Li+. The observations are consistent with a reversible disproportionation of part of the LiMn2O4 into Li2Mn2O4 and a lithium-deficient spinel. With extended constant current cycling part of the Li2Mn2O4 degrades to the Mn2O3 and the process is no longer reversible.

  9. Electric-Field Modulation of Curie Temperature in (Ga, Mn)As Field-Effect Transistor Structures with Varying Channel Thickness and Mn Compositions

    SciTech Connect (OSTI)

    Nishitani, Y.; Endo, M.; Chiba, D.; Matsukura, F.; Ohno, H.

    2010-01-04

    We have investigated the change of T{sub C} of ferromagnetic semiconductor (Ga, Mn)As by changing hole concentration p. The field effect transistor structure was utilized to change p. The relation T{sub C}propor top{sup 0.2} is obtained for three samples, despite the difference of their Mn composition and thickness, indicating that the relation holds over 2 decades of p.

  10. K and Mn co-doped BaCd{sub 2}As{sub 2}: A hexagonal structured...

    Office of Scientific and Technical Information (OSTI)

    K and Mn co-doped BaCdsub 2Assub 2: A hexagonal structured bulk diluted magnetic semiconductor with large magnetoresistance Citation Details In-Document Search Title: K and Mn ...

  11. Scanning tunneling microscopy reveals LiMnAs is a room temperature anti-ferromagnetic semiconductor

    SciTech Connect (OSTI)

    Wijnheijmer, A. P.; Koenraad, P. M.; Marti, X.; Holy, V.; Cukr, M.; Novak, V.; Jungwirth, T.

    2012-03-12

    We performed scanning tunneling microscopy and spectroscopy on a LiMnAs(001) thin film epitaxially grown on an InAs(001) substrate by molecular beam epitaxy. While the in situ cleavage exposed only the InAs(110) non-polar planes, the cleavage continued into the LiMnAs thin layer across several facets. We combined both topography and current mappings to confirm that the facets correspond to LiMnAs. By spectroscopy we show that LiMnAs has a band gap. The band gap evidenced in this study, combined with the known Neel temperature well above room temperature, confirms that LiMnAs is a promising candidate for exploring the concepts of high temperature semiconductor spintronics based on antiferromagnets.

  12. Magnetic properties and photoabsorption of the Mn-doped CeO{sub 2} nanorods

    SciTech Connect (OSTI)

    Xia, Chuanhui; Science College of Chongqing Jiaotong University, Chongqing 400074 ; Hu, Chenguo; Chen, Peng; Wan, Buyong; He, Xiaoshan; Tian, Yongshu; Chongqing Communication College, Chongqing 400035

    2010-07-15

    Mn-doped CeO{sub 2} nanorods have been prepared from CeO{sub 2} particles through a facile composite-hydroxide-mediated (CHM) approach. The analysis from X-ray photoelectron spectroscopy indicates that the manganese doped in CeO{sub 2} exists as Mn{sup 2+}. The magnetic measurement of the Mn-doped CeO{sub 2} nanorods exhibits an enhanced ferromagnetic property at room temperature with a remanence magnetization (Mr) of 1.36 x 10{sup -3} emu/g and coercivity (Hc) of 22 Oe. Comparative UV-visible spectra reveal the shift of the absorption peak of the CeO{sub 2} from ultraviolet region to visible light region after being doped with Mn. The room temperature ferromagnetic properties and light absorption of the Mn-doped CeO{sub 2} nanorods would have potential applications in photocatalysis and building of photovoltaic devices.

  13. Giant atomic displacement at a magnetic phase transition in metastable Mn3O4

    SciTech Connect (OSTI)

    Hirai, Shigeto; Moreira Dos Santos, Antonio F; Shapiro, Max C; Molaison, Jamie J; Pradhan, Neelam; Guthrie, Malcolm; Tulk, Christopher A; Fisher, Ian R; Mao, Wendy

    2013-01-01

    We present x-ray, neutron scattering, and heat capacity data that reveal a coupled first-order magnetic and structural phase transition of the metastable mixed-valence postspinel compound Mn3O4 at 210 K. Powder neutron diffraction measurements reveal a magnetic structure in which Mn3+ spins align antiferromagnetically along the edge-sharing a axis, with a magnetic propagation vector k = [1/2,0,0]. In contrast, the Mn2+ spins, which are geometrically frustrated, do not order until a much lower temperature. Although the Mn2+ spins do not directly participate in the magnetic phase transition at 210 K, structural refinements reveal a large atomic shift at this phase transition, corresponding to a physical motion of approximately 0.25 angstrom, even though the crystal symmetry remains unchanged. This "giant" response is due to the coupled effect of built-in strain in the metastable postspinel structure with the orbital realignment of the Mn3+ ion.

  14. Secretary Chu Announces Agreement on FutureGen Project in Mattoon, IL |

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

    Department of Energy Agreement on FutureGen Project in Mattoon, IL Secretary Chu Announces Agreement on FutureGen Project in Mattoon, IL June 12, 2009 - 12:00am Addthis Washington, D.C. - U.S. Secretary of Energy Steven Chu today announced an agreement with the FutureGen Alliance that advances the construction of the first commercial scale, fully integrated, carbon capture and sequestration project in the country in Mattoon, Illinois. "This important step forward for FutureGen reflects

  15. Ferromagnetic (Ga,Mn)As nanostructures for spintronic applications

    SciTech Connect (OSTI)

    Wosinski, Tadeusz; Andrearczyk, Tomasz; Figielski, Tadeusz; Makosa, Andrzej; Wrobel, Jerzy; Sadowski, Janusz

    2013-12-04

    Magneto-resistive, cross-like nanostructures have been designed and fabricated by electron-beam lithography patterning and chemical etching from thin epitaxial layers of the ferromagnetic semiconductor (Ga,Mn)As. The nanostructures, composed of two perpendicular nanostripes crossing in the middle of their length, represent four-terminal devices, in which an electric current can be driven through any of the two nanostripes. In these devices, a novel magneto-resistive memory effect, related to a rearrangement of magnetic domain walls in the central part of the device, has been demonstrated. It consists in that the zero-field resistance of a nanostripe depends on the direction of previously applied magnetic field. The nanostructures can thus work as two-state devices providing basic elements of nonvolatile memory cells.

  16. 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.

  17. U.S. Energy Information Administration | Annual Coal Report 2014

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

    5. Coal Consumers in the Manufacturing and Coke Sectors, 2014 Company Name Plant Location Top Ten Manufacturers American Crystal Sugar Co MN, ND Archer Daniels Midland IA, IL, MN, NE Carmeuse Lime Stone Inc AL, IN, KY, MI, OH, PA, TN, WI Cemex Inc AL, CA, CO, FL, GA, KY, OH, TN, TX Dakota Gasification Company ND Eastman Chemical Company TN Georgia-Pacific Consumer Products LP AL, GA, OK, VA, WI Holcim (US) Inc AL, CO, MD, MO, MT, OK, SC, TX, UT NewPage Corporation MD, MI, WI U S Steel

  18. SAS Output

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

    5. Coal Consumers in the Manufacturing and Coke Sectors, 2014" "Company Name","Plant Location" "Top Ten Manufacturers" "American Crystal Sugar Co","MN, ND" "Archer Daniels Midland","IA, IL, MN, NE" "Carmeuse Lime Stone Inc","AL, IN, KY, MI, OH, PA, TN, WI" "Cemex Inc","AL, CA, CO, FL, GA, KY, OH, TN, TX" "Dakota Gasification Company","ND" "Eastman Chemical

  19. Ab initio study of Fe{sub 2}MnZ (Al, Si, Ge) Heusler alloy using GGA approximation

    SciTech Connect (OSTI)

    Jain, Vivek Kumar Jain, Vishal Lakshmi, N. Venugopalan, K.

    2014-04-24

    Density functional theory based on FP-LAPW method used to investigate the electronic structure of Fe{sub 2}MnZ, shows that the total spin magnetic moment shows a trend consistent with the Slater–Pauling curve. The Fe and Mn magnetic moment depend on choice of Z element although the magnetic moment of Z element is negative and less than 0.1 μ{sub B}. Spin polarization calculations evidence 100% spin polarization for Fe{sub 2}MnSi. Fe{sub 2}MnAl and Fe{sub 2}MnGe show metallic behavior with 93%, 98% spin polarization.

  20. Quantum Anomalous Hall Effect in Hg_1-yMn_yTe Quantum Wells

    SciTech Connect (OSTI)

    Liu, Chao-Xing; Qi, Xiao-Liang; Dai, Xi; Fang, Zhong; Zhang, Shou-Cheng; /Stanford U., Phys. Dept.

    2010-03-19

    The quantum Hall effect is usually observed when the two-dimensional electron gas is subjected to an external magnetic field, so that their quantum states form Landau levels. In this work we predict that a new phenomenon, the quantum anomalous Hall effect, can be realized in Hg{sub 1-y}Mn{sub y}Te quantum wells, without the external magnetic field and the associated Landau levels. This effect arises purely from the spin polarization of the Mn atoms, and the quantized Hall conductance is predicted for a range of quantum well thickness and the concentration of the Mn atoms. This effect enables dissipationless charge current in spintronics devices.

  1. Recent progress of magnetocaloric effect and magnetic refrigerant materials of Mn compounds (invited)

    SciTech Connect (OSTI)

    Wada, H. Takahara, T.; Katagiri, K.; Ohnishi, T.; Soejima, K.; Yamashita, K.

    2015-05-07

    Magnetocaloric and related properties of Ru and Ni substituted (MnFe){sub 2}(PSi) are presented. It is found that Ru and Ni are effective doping elements to reduce the thermal hysteresis of (MnFe){sub 2}(PSi). The origin of the thermal hysteresis is discussed on the basis of a thermodynamic model. It is shown that the elastic energy is responsible for the thermal hysteresis. We also show recent developments of the production process of Mn compounds in an industrial scale.

  2. Unoccupied electronic structure of Ni2MnGa ferromagnetic shape memory alloy

    SciTech Connect (OSTI)

    Maniraj, M.; D?Souza, S. W.; Rai, Abhishek; Schlagel, D. L.; Lograsso, T. A.; Chakrabarti, Aparna; Barman, S. R.

    2015-08-20

    Momentum resolved inverse photoemission spectroscopy measurements show that the dispersion of the unoccupied bands of Ni2MnGa is significant in the austenite phase. Furthermore, in the martensite phase, it is markedly reduced, which is possibly related to the structural transition to an incommensurate modulated state in the martensite phase. Finally, based on the first principle calculations of the electronic structure of NiMnGa, we show that the modification of the spectral shape with surface composition is related to change in the hybridization between the Mn 3d and Ni 3d-like states that dominate the unoccupied conduction band.

  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. Unique light-induced degradation in yellow-emitting K₂SiF₆:Mn²⁺ phosphor

    SciTech Connect (OSTI)

    Oyama, Takuya; Adachi, Sadao

    2014-10-07

    Photo-induced luminescence intensity degradation in yellow-emitting K₂SiF₆:Mn²⁺ phosphor is studied using x-ray diffraction measurement, photoluminescence (PL) analysis, PL excitation (PLE) spectroscopy, PL decay analysis, and electron spin resonance (ESR) measurement. The yellow-emitting K₂SiF₆:Mn²⁺ phosphor exhibits remarkable degradation in the PL intensity under Xe lamp exposure. Coherent laser irradiation also induces degradation and its degree is in the order of He–Cd (λ = 325 nm) > Ar⁺ (488 nm) > He–Ne laser (632.8 nm). The degradation mechanism is proposed to be due to change in the valence state of manganese ions from Mn²⁺ to Mn³⁺ by the photooxidation (Mn²⁺ → Mn³⁺) or disproportionation reaction (2Mn²⁺ → Mn⁺ + Mn³⁺). The ESR measurement confirms the decreased Mn²⁺ spin density in the sample exposed with Xe lamp. The PLE spectrum suggests that the excitation of Mn³⁺ ions occurs through energy transfer upon absorption of exciting radiation by the Mn²⁺ ions. Thermal annealing of the degraded samples at ≥200 °C causes a blueshift in the PL emission band with an appearance of the Mn⁴⁺-related sharp red emission lines.

  5. Planar Hall effect in Y{sub 3}Fe{sub 5}O{sub 12}/IrMn films

    SciTech Connect (OSTI)

    Zhang, X. Zou, L. K.

    2014-12-29

    The planar Hall effect of IrMn on an yttrium iron garnet (YIG = Y{sub 3}Fe{sub 5}O{sub 12}) was measured in the magnetic field rotating in the film plane. The magnetic field angular dependence of planar Hall resistance (PHR) was observed in YIG/IrMn bilayer at different temperatures, while the Gd{sub 3}Ga{sub 5}O{sub 12}/IrMn film shows constant PHR for different magnetic field angles at both 10 K and 300 K. This provides evidence that IrMn has interfacial spins which can be led by ferrimagnetic layer in YIG/IrMn structure. A hysteresis can be observed in PHR-magnetic field angle loop of YIG/IrMn film at 10 K, indicative of the irreversible switching of IrMn interfacial spins at low temperature.

  6. First-principles study of spin-transfer torque in Co{sub 2}MnSi/Al/Co{sub 2}MnSi spin-valve

    SciTech Connect (OSTI)

    Tang, Ling Yang, Zejin

    2013-11-21

    The spin-transfer torque (STT) in Co{sub 2}MnSi(CMS)/Al/Co{sub 2}MnSi spin-valve system with and without interfacial disorder is studied by a first-principles noncollinear wave-function-matching method. It is shown that in the case of clean interface the angular dependence of STT for CoCo/Al (the asymmetry parameter Λ≈4.5) is more skewed than that for MnSi/Al (Λ≈2.9), which suggests the clean CoCo/Al architecture is much more efficient for the application on radio frequency oscillation. We also find that even with interfacial disorder the spin-valve of half-metallic CMS still has a relatively large parameter Λ compared to that of conventional ferromagnet. In addition, for clean interface the in-plane torkance of MnSi/Al is about twice as large as that of CoCo/Al. However, as long as the degree of interfacial disorder is sufficiently large, the CoCo/Al and MnSi/Al will show approximately the same magnitude of in-plane torkance. Furthermore, our results demonstrate that CMS/Al/CMS system has very high efficiency of STT to switch the magnetic layer of spin-valve.

  7. Expectations for the hard x-ray continuum and gamma-ray line fluxes from the typE IA supernova SN 2014J in M82

    SciTech Connect (OSTI)

    The, Lih-Sin [Department of Physics and Astronomy, Clemson University, SC 29634 (United States); Burrows, Adam, E-mail: tlihsin@clemson.edu, E-mail: burrows@astro.princeton.edu [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States)

    2014-05-10

    The hard X-ray continuum and gamma-ray lines from a Type Ia supernova dominate its integrated photon emissions and can provide unique diagnostics of the mass of the ejecta, the {sup 56}Ni yield and spatial distribution, its kinetic energy and expansion speed, and the mechanism of explosion. Such signatures and their time behavior 'X-ray' the bulk debris field in direct fashion, and do not depend on the ofttimes problematic and elaborate UV, optical, and near-infrared spectroscopy and radiative transfer that have informed the study of these events for decades. However, to date no hard photons have ever been detected from a Type Ia supernova in explosion. With the advent of the supernova SN 2014J in M82, at a distance of ?3.5 Mpc, this situation may soon change. Both NuSTAR and INTEGRAL have the potential to detect SN 2014J, and, if spectra and light curves can be measured, would usefully constrain the various explosion models published during the last ?30 yr. In support of these observational campaigns, we provide predictions for the hard X-ray continuum and gamma-line emissions for 15 Type Ia explosion models gleaned from the literature. The model set, containing as it does deflagration, delayed detonation, merger detonation, pulsational delayed detonation, and sub-Chandrasekhar helium detonation models, collectively spans a wide range of properties, and hence signatures. We provide a brief discussion of various diagnostics (with examples), but importantly make the spectral and line results available electronically to aid in the interpretation of the anticipated data.

  8. THE EFFECT OF THE PRE-DETONATION STELLAR INTERNAL VELOCITY PROFILE ON THE NUCLEOSYNTHETIC YIELDS IN TYPE Ia SUPERNOVA

    SciTech Connect (OSTI)

    Kim, Yeunjin; Jordan, G. C. IV; Graziani, Carlo; Lamb, D. Q.; Truran, J. W.; Meyer, B. S.

    2013-07-01

    A common model of the explosion mechanism of Type Ia supernovae is based on a delayed detonation of a white dwarf. A variety of models differ primarily in the method by which the deflagration leads to a detonation. A common feature of the models, however, is that all of them involve the propagation of the detonation through a white dwarf that is either expanding or contracting, where the stellar internal velocity profile depends on both time and space. In this work, we investigate the effects of the pre-detonation stellar internal velocity profile and the post-detonation velocity of expansion on the production of {alpha}-particle nuclei, including {sup 56}Ni, which are the primary nuclei produced by the detonation wave. We perform one-dimensional hydrodynamic simulations of the explosion phase of the white dwarf for center and off-center detonations with five different stellar velocity profiles at the onset of the detonation. In order to follow the complex flows and to calculate the nucleosynthetic yields, approximately 10,000 tracer particles were added to every simulation. We observe two distinct post-detonation expansion phases: rarefaction and bulk expansion. Almost all the burning to {sup 56}Ni occurs only in the rarefaction phase, and its expansion timescale is influenced by pre-existing flow structure in the star, in particular by the pre-detonation stellar velocity profile. We find that the mass fractions of the {alpha}-particle nuclei, including {sup 56}Ni, are tight functions of the empirical physical parameter {rho}{sub up}/v{sub down}, where {rho}{sub up} is the mass density immediately upstream of the detonation wave front and v{sub down} is the velocity of the flow immediately downstream of the detonation wave front. We also find that v{sub down} depends on the pre-detonation flow velocity. We conclude that the properties of the pre-existing flow, in particular the internal stellar velocity profile, influence the final isotopic composition of burned

  9. Gorchakova-IA

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

    Atl anta, Georgia, March 19-23, 2001 1 Estimate of Horizontal Cloud Inhomogeneity Effect on Solar Radiative Fluxes for Conditions of Winter Zvenigorod Experiment I. A. Gorchakova, G. S. Golitsyn, and I. I. Mokhov Oboukhov Institute of Atmospheric Physics Russian Academy of Sciences Moscow, Russia T. B. Zhuravleva Institute of Atmospheric Optics Tomsk, Russia Introduction Study of physical phenomena determining large-scale dynamical and energetic processes in the atmosphere requires quite full

  10. Type Ia Supernovae

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

    that the universe is undergoing an accelerated expansion - a result which fits the General Relativity if a yet unknown form of "dark" energy is assumed to dominate the...

  11. IA Blog Archive

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

    2014 21:03:00 +0000 921386 at http:energy.gov Ministers Meet in Addis Ababa for U.S.-Africa Energy Ministerial http:energy.goviaarticlesministers-meet-addis-ababa-us-africa-...

  12. IA News Archive

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

    Dilma Rousseff of Brazil and he announced the creation of a Strategic Energy Dialogue (SED) to support the two countries' common goals of developing safe, secure and affordable...

  13. File:USDA-CE-Production-GIFmaps-MN.pdf | Open Energy Information

    Open Energy Info (EERE)

    MN.pdf Jump to: navigation, search File File history File usage Minnesota Ethanol Plant Locations Size of this preview: 776 600 pixels. Full resolution (1,650 1,275...

  14. Unoccupied electronic structure of Ni2MnGa ferromagnetic shape...

    Office of Scientific and Technical Information (OSTI)

    shape memory alloy This content will become publicly available on August 20, 2016 Prev Next Title: Unoccupied electronic structure of Ni2MnGa ferromagnetic shape memory alloy ...

  15. Microstructure and Mechanical Properties of Two-Phase Fe30Ni20Mn20Al30...

    Office of Scientific and Technical Information (OSTI)

    Title: Microstructure and Mechanical Properties of Two-Phase Fe30Ni20Mn20Al30 Alloy Authors: Wu, Xiaolan 1 ; Baker, Ian 1 ; Wu, H 1 ; Miller, Michael K 2 ; More, Karren ...

  16. Magnetocaloric effect of Pr2Fe17-x Mn x alloys (Journal Article...

    Office of Scientific and Technical Information (OSTI)

    SciTech Connect Search Results Journal Article: Magnetocaloric effect of Pr2Fe17-x Mn x ... OSTI Identifier: 1221829 Report Number(s): IS-J 8426 Journal ID: ISSN 1001-0521; PII: 134 ...

  17. Effect of Mn substitution on the transport properties of co-sputtered...

    Office of Scientific and Technical Information (OSTI)

    on the transport properties of co-sputtered Fesub 3-xMnsub xSi epilayers Citation Details In-Document Search Title: Effect of Mn substitution on the transport properties of ...

  18. X-Ray Spectroscopy of the Mn(4) Ca Cluster in the Water-Oxidation...

    Office of Scientific and Technical Information (OSTI)

    Ca Cluster in the Water-Oxidation Complex of Photosystem II Citation Details In-Document Search Title: X-Ray Spectroscopy of the Mn(4) Ca Cluster in the Water-Oxidation Complex ...

  19. Electrochemical Performances of LiMnPO4 Synthesized from Non...

    Office of Scientific and Technical Information (OSTI)

    Li1.1MnPO4 exhibits the most stable cycling ability probably because of the existence of a trace amount of Li3PO4 impurity that functions as a solid-state electrolyte on...

  20. Spectroscopic properties of (PVA+ZnO):Mn{sup 2+} polymer films

    SciTech Connect (OSTI)

    Rani, Ch.; Raju, D. Siva; Bindu, S. Hima; Krishna, J. Suresh; Raju, Ch. Linga

    2015-05-15

    Electron Paramagnetic Resonance (EPR), optical absorption and infrared spectral studies have been carried out on Mn{sup 2+} ions doped in poly(vinyl alcohol) complexed with zinc oxide polymer films prepared by solution cast technique. The EPR spectra of 1 mol% Mn{sup 2+} ions doped polymer complex (PVA+ZnO) at room temperature exhibit sextet hyperfine structure (hfs), centered at 2.01. The spin-Hamiltonian parameter values indicate that the ground state of Mn{sup 2+} ion in d{sup 5} and the site symmetry around Mn{sup 2+} ions in tetragonally distorted octa hedral site. The optical absorption spectra exhibits two bands centered at 275nm at 437nm. The FTIR spectrum exhibits bands characteristic of stretching and banding vibrations of O-H, C-H and C=C groups.

  1. Modeling and Characterization of the Magnetocaloric Effect in Ni2MnGa Materials

    SciTech Connect (OSTI)

    Nicholson, Don M; Odbadrakh, Khorgolkhuu; Rios, Orlando; Hodges, Jason P; Ludtka, Gerard Michael; Porter, Wallace D; Sefat, A. S.; Rusanu, Aurelian; Evans III, Boyd Mccutchen

    2012-01-01

    Magnetic shape memory alloys have great promise as magneto-caloric effect refrigerant materials due to their combined magnetic and structural transitions. Computational and experimental research is reported on the Ni2MnGa material system. The magnetic states of this system have been explored using the Wang-Landau statistical approach in conjunction with the Locally Self-consistent Multiple-Scattering (LSMS) method to explore the magnetic states responsible for the magnet-caloric effect in this material. The effects of alloying agents on the transition temperatures of the Ni2MnGa alloy were investigated using differential scanning calorimetry (DSC) and superconducting quantum interference device (SQUID). Neutron scattering experiments were performed to observe the structural and magnetic phase transformations at the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory (ORNL) on alloys of Ni-Mn-Ga and Ni-Mn-Ga-Cu-Fe. Data from the observations are discussed in comparison with the computational studies.

  2. In-situ Electrical Conductivity of LixMnO2 Nanowires as a Function...

    Office of Scientific and Technical Information (OSTI)

    of LixMnO2 Nanowires as a Function of "x" and Size Authors: Le, Mya ; Liu, Yu ; Wang, Hui ; Dutta, Rajen ; Yan, Wenbo ; Hemminger, John C ; Wu, Ruqian ; Penner, Reginald...

  3. Pressure-Induced Metallization of the Mott Insulator MnO (Journal...

    Office of Scientific and Technical Information (OSTI)

    Pressure-Induced Metallization of the Mott Insulator MnO Citation ... Publication Date: 2004-01-12 OSTI Identifier: 15013737 Report Number(s): UCRL-JRNL-201933 Journal ID: ISSN ...

  4. Synthesis and characterization of MnPS{sub 3} for hydrogen sorption

    SciTech Connect (OSTI)

    Ismail, N.; Temerk, Y.M.; El-Meligi, A.A.; Badr, M.A.; Madian, M.

    2010-05-15

    Single phase MnPS{sub 3} powder was prepared by solid state reaction between Mn, S and P carried out at 650 deg. C in evacuated silica tube. The structure, morphology and sorption characteristics of the prepared solid were investigated. The results revealed that the obtained MnPS{sub 3} compound was capable of adsorbing 3.5 wt% hydrogen at -193 deg. C and a pressure of 30 bar. Little amount of hydrogen (0.07 wt%) was adsorbed at room temperature. The hydrogen adsorption/desorption cycles at various temperatures did not result in irreversible chemical structural changes of the MnPS{sub 3} compound, but the microstructure after hydrogen cycling diminished and became finer. - Graphical abstract: Atomic building of MPS{sub 3}

  5. Understanding the Structural and Electronic Evolution of Li2MnO3 During

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

    Electron Irradiation Via Electron Microscopy - Joint Center for Energy Storage Research November 17, 2014, Research Highlights Understanding the Structural and Electronic Evolution of Li2MnO3 During Electron Irradiation Via Electron Microscopy In-situ electron beam irradiation induces localized pockets of damage (a) and (b) characterized by the Mn atoms migrating to occupy Li sites, as shown in the annular bright field image of (c). This effect is clearly visible in an intensity line profile

  6. The role of C and Mn at the austenite/pearlite reaction front during non-steady-state pearlite growth in a Fe-C-Mn steel

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

    Aranda, M. M.; Rementeria, R.; Poplawsky, Jonathan D.; Urones-Garrote, E.; Capdevila, Carlos

    2015-04-18

    The role of C and Mn during the growth of pearlite under non-steady state conditions is analyzed by comparing the phase compositions of austenite, ferrite and cementite (γ+α+θ) through the use of transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS), and atom probe tomography (APT) measurements across the austenite/pearlite interface. Furthermore, a local Mn enrichment and C depletion at the austenite/pearlite interface has been measured, which causes a change in the driving force with time during divergent pearlite growth.

  7. The structure of the Caenorhabditis elegans manganese superoxide dismutase MnSOD-3-azide complex

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

    Hunter, Gary J.; Trinh, Chi H.; Bonetta, Rosalin; Stewart, Emma E.; Cabelli, Diane E.; Hunter, Therese

    2015-08-27

    C. elegans MnSOD-3 has been implicated in the longevity pathway and its mechanism of catalysis is relevant to the aging process and carcinogenesis. The structures of MnSOD-3 provide unique crystallographic evidence of a dynamic region of the tetrameric interface (residues 41–54). We have determined the structure of the MnSOD-3-azide complex to 1.77-Å resolution. The analysis of this complex shows that the substrate analog, azide, binds end-on to the manganese center as a sixth ligand and that it ligates directly to a third and new solvent molecule also positioned within interacting distance to the His30 and Tyr34 residues of the substratemore » access funnel. This is the first structure of a eukaryotic MnSOD-azide complex that demonstrates the extended, uninterrupted hydrogen-bonded network that forms a proton relay incorporating three outer sphere solvent molecules, the substrate analog, the gateway residues, Gln142, and the solvent ligand. This configuration supports the formation and release of the hydrogen peroxide product in agreement with the 5-6-5 catalytic mechanism for MnSOD. The high product dissociation constant k₄ of MnSOD-3 reflects low product inhibition making this enzyme efficient even at high levels of superoxide.« less

  8. Hydrothermal synthesis of Mn vanadate nanosheets and visible-light photocatalytic performance for the degradation of methyl blue

    SciTech Connect (OSTI)

    Pei, L.Z. Xie, Y.K.; Pei, Y.Q.; Jiang, Y.X.; Yu, H.Y.; Cai, Z.Y.

    2013-07-15

    Graphical abstract: - Highlights: Mn vanadate nanosheets have been synthesized by simple hydrothermal process. The formation of Mn vanadate nanosheets can be controlled by growth conditions. Mn vanadate nanosheets exhibit good photocatalytic activities for methyl blue. - Abstract: Mn vanadate nanosheets have been synthesized via a facile hydrothermal route using ammonium metavanadate and Mn acetate as the raw materials, polyvinyl pyrrolidone (PVP) as the surfactant. X-ray diffraction (XRD) shows that the Mn vanadate nanosheets are composed of monoclinic MnV{sub 2}O{sub 6} phase. Scanning electron microscopy (SEM) observation indicates that the nanosheets have the average thickness of about 50 nm, length of 210 ?m and width of 800 nm to 2 ?m. The growth process of the Mn vanadate nanosheets has also been discussed based on the analysis of the roles of the growth conditions on the formation of the Mn vanadate nanosheets. The nanosheets show good photocatalytic activities for the degradation of methylene blue (MB) under visible light irradiation. About 72.96% MB can be degraded after visible light irradiation for 1 h over 10 mg Mn vanadate nanosheets in 10 mL MB solution with the concentration of 10 mg L{sup ?1}.

  9. IL.26

    Office of Legacy Management (LM)

    ... by the AEC Health and Safety Laboratory; (4) establishment of a program for area clearance after each cycle; (5) supply of the uranium billets allocated for a work cycle ...

  10. DOE Zero Energy Ready Home Case Study: StreetScape Development, LLC, Libertyville, IL, Custom

    Broader source: Energy.gov [DOE]

    Case study of a DOE Zero Energy Ready Home in Libertyville, IL, that scored HERS 45 without PV. This 2,763-square-foot custom home has advanced framed walls with R-20 of open-cell spray foam, R-49 open-cell spray-foam sealed attic, an HRV, and a tankless water heater for hydro coil furnace with high-velocity, small-diameter ducts.

  11. Inverse magnetocaloric effect in Mn{sub 2}NiGa and Mn{sub 1.75}Ni{sub 1.25}Ga magnetic shape memory alloys

    SciTech Connect (OSTI)

    Singh, Sanjay Barman, S. R.; Esakki Muthu, S.; Arumugam, S.; Senyshyn, A.; Rajput, P.; Suard, E.

    2014-02-03

    Inverse magnetocaloric effect is demonstrated in Mn{sub 2}NiGa and Mn{sub 1.75}Ni{sub 1.25}Ga magnetic shape memory alloys. The entropy change at the martensite transition is larger in Mn{sub 1.75}Ni{sub 1.25}Ga, and it increases linearly with magnetic field in both the specimens. Existence of inverse magnetocaloric effect is consistent with the observation that magnetization in the martensite phase is smaller than the austenite phase. Although the Mn content is smaller in Mn{sub 1.75}Ni{sub 1.25}Ga, from neutron diffraction, we show that the origin of inverse magnetocaloric effect is the antiferromagnetic interaction between the Mn atoms occupying inequivalent sites.

  12. The prominent role of oxygen in the multiferroicity of DyMnO3 and TbMnO3: a resonant soft x-ray scattering spectroscopy study

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

    S. W. Huang; Lee, J. M.; Jeng, H. -T.; Shao, Y.; Wray, L. A.; Chen, J. M.; Qiao, R.; Yang, W. L.; Cao, Y.; Lin, J. -Y.; et al

    2016-07-21

    Oxygen is known to play an important role in the multiferroicity of rare earth manganites; however, how this role changes with rare earth elements is still not fully understood. To address this question, we have used resonant soft x-ray scattering spectroscopy to study the F-type (0; ; 0) diffraction peak from the antiferromagnetic order in DyMnO3 and TbMnO3. We focus on the measurements at O K-edge of these two manganites, supplemented by the results at Mn L2- and Dy M5-edge of DyMnO3. We show that the electronic states of di erent elements are coupled more strongly in DyMnO3 than inmore » TbMnO3, presumably due to the stronger lattice distortion and the tendency to develop E-type antiferromagnetism in the ferroelectric state that promote the orbital hybridization. We also show that the anomaly in the correlation length of (0; ; 0) peak in DyMnO3 signifies the exchange interaction between Mn and rare earth spins, which is absent in TbMnO3. Our findings reveal the prominent role of oxygen orbitals in the multiferroicity of rare earth manganites and the distinct energetics between them.« less

  13. Synthesis of spherical LiMnPO{sub 4}/C composite microparticles

    SciTech Connect (OSTI)

    Bakenov, Zhumabay; Taniguchi, Izumi

    2011-08-15

    Highlights: {yields} We could prepare LiMnPO{sub 4}/C composites by a novel preparation method. {yields} The LiMnPO{sub 4}/C composites were spherical particles with a mean diameter of 3.65 {mu}m. {yields} The LiMnPO{sub 4}/C composite cathode exhibited 112 mAh g{sup -1} at 0.05 C. {yields} It also showed a good rate capability up to 5 C at room temperature and 55 {sup o}C. -- Abstract: Spherical LiMnPO{sub 4}/C composite microparticles were prepared by a combination of spray pyrolysis and spray drying followed by heat treatment and examined as a cathode material for lithium batteries. The structure, morphology and electrochemical performance of the resulting spherical LiMnPO{sub 4}/C microparticles were characterized by X-ray diffraction, field-emission scanning electron microscopy, transmission electronic microscopy and standard electrochemical techniques. The final sample was identified as a single phase orthorhombic structure of LiMnPO{sub 4} and spherical powders with a geometric mean diameter of 3.65 {mu}m and a geometric standard deviation of 1.34. The electrochemical cells contained the spherical LiMnPO{sub 4}/C microparticles exhibited first discharge capacities of 112 and 130 mAh g{sup -1} at 0.05 C at room temperature and 55 {sup o}C, respectively. These also showed a good rate capability up to 5 C at room temperature and 55 {sup o}C.

  14. 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.

  15. Demonstration Assessment of Light-Emitting Diode (LED) Accent Lighting at the Field Museum in Chicago, IL

    SciTech Connect (OSTI)

    Myer, Michael; Kinzey, Bruce R.

    2010-12-10

    This report reviews a demonstration of light-emitting diode (LED) accent lighting compared to halogen (typical) accent lighting in a gallery of the Field Museum in Chicago, IL.

  16. Peculiarly strong room-temperature ferromagnetism from low Mn-doping in ZnO grown by molecular beam epitaxy

    SciTech Connect (OSTI)

    Zuo Zheng; Morshed, Muhammad; Liu Jianlin; Beyermann, W. P.; Zheng Jianguo; Xin Yan

    2013-03-15

    Strong room-temperature ferromagnetism is demonstrated in single crystalline Mn-doped ZnO thin films grown by molecular beam epitaxy. Very low Mn doping concentration is investigated, and the measured magnetic moment is much larger than what is expected for an isolated ion based on Hund's rules. The ferromagnetic behavior evolves with Mn concentration. Both magnetic anisotropy and anomalous Hall effect confirm the intrinsic nature of ferromagnetism. While the Mn dopant plays a crucial role, another entity in the system is needed to explain the observed large magnetic moments.

  17. Mn-Stabilized Zirconia: From Imitation Diamonds to a New Potential High-T{sub C} Ferromagnetic Spintronics Material

    SciTech Connect (OSTI)

    Ostanin, S.; Ernst, A.; Sandratskii, L. M.; Bruno, P.; Daene, M.; Hergert, W.; Mertig, I.; Hughes, I. D.; Staunton, J. B.; Kudrnovsky, J.

    2007-01-05

    From the basis of ab initio electronic structure calculations which include the effects of thermally excited magnetic fluctuations, we predict Mn-stabilized cubic zirconia to be ferromagnetic above 500 K. We find this material, which is well known both as an imitation diamond and as a catalyst, to be half-metallic with the majority and minority spin Mn impurity states lying in zirconia's wide gap. The Mn concentration can exceed 40%. The high-T{sub C} ferromagnetism is robust to oxygen vacancy defects and to how the Mn impurities are distributed on the Zr fcc sublattice. We propose this ceramic as a promising future spintronics material.

  18. Properties of Ga{sub 1-x}Mn{sub x}As with high x (>0.1)

    SciTech Connect (OSTI)

    Chiba, D.; Yu, K. M.; Walukiewicz, W.; Nishitani, Y.; Matsukura, F.; Ohno, H.

    2008-04-01

    We have investigated the magnetic and the crystalline properties of a set of Ga{sub 1-x}Mn{sub x}As layers with high nominal Mn compositions (x=0.101-0.198). Magnetization measurements and combined channeling Rutherford backscattering (c-RBS) and particle induced x-ray emission (c-PIXE) measurements have been performed to determine the effective Mn composition x{sub eff} and the fraction of Mn atoms at various lattice sites. Here, x{sub eff} determined from magnetization measurements, which increases with increasing x, is consistent with the results determined from c-RBS-PIXE measurements.

  19. Enhanced ferromagnetic order in Sr{sub 4}Mn{sub 3}O{sub 3}(GeO{sub 4}){sub 3} featuring canted [MnO{sub 4}]{sub ∞} spin chains of mixed-valent Mn(III)/Mn(IV). Aliovalent substitution of the Sr{sub 4−x}Ln{sub x}Mn{sup III}{sub 2+x}Mn{sup IV}{sub 1−x}O{sub 3}(GeO{sub 4}){sub 3} solid-solution

    SciTech Connect (OSTI)

    West, J. Palmer; Sulejmanovic, Dino; Becht, Gregory; He, Jian; Hitchcock, Dale; Yan, Yonggao; Hwu, Shiou-Jyh

    2013-10-15

    Crystals of Sr{sub 4−x}Ln{sub x}Mn{sub 3}O{sub 3}(GeO{sub 4}){sub 3} (x=0; x∼0.15 for Ln=La, Pr, Nd, Sm. Eu, Gd, Dy; x∼0.3 for Ln=Gd) were isolated upon using high-temperature, solid-state methods in molten-salt media. These compounds are isostructural with the previously reported Na{sub 3}LnMn{sub 3}O{sub 3}(AsO{sub 4}){sub 3} (Ln=La, Sm, Gd) series that contains the same [MnO{sub 4}]{sub ∞} spin chains. The synthesis of the Sr{sub 4}Mn{sub 3}O{sub 3}(GeO{sub 4}){sub 3} (x=0) phase was carried out by a double aliovalent substitution with respect to the Sr{sup 2+} and Ge{sup 4+} ions that replace Na{sup +}/Ln{sup 3+} and As{sup 5+} in Na{sub 3}LnMn{sub 3}O{sub 3}(AsO{sub 4}){sub 3}, respectively. The title series contains mixed-valent Mn(III)/Mn(IV) and shows a limited range of solid solution, both of which were not observed in the previously reported Na{sub 3}LnMn{sub 3}O{sub 3}(AsO{sub 4}){sub 3} series. To form the Sr{sub 4−x}Ln{sub x}Mn{sub 3}O{sub 3}(GeO{sub 4}){sub 3} solid solution, one of the Sr{sup 2+} sites, i.e., the original Ln-site in Na{sub 3}LnMn{sub 3}O{sub 3}(AsO{sub 4}){sub 3}, is partially substituted by Ln{sup 3+} in a statistical disorder of Sr{sub 1−x}/Ln{sub x}. Initial magnetic investigations of selected derivatives reveal higher ferromagnetic ordering temperatures than those reported for the Na{sub 3}LnMn{sub 3}O{sub 3}(AsO{sub 4}){sub 3} series, presumably attributed to a lesser degree of canting as a result of introducing non-Jahn–Teller Mn{sup 4+} ions. Also intriguing is the observation of multiple anomalies at low temperatures which appear to be of electronic origins. - Graphical abstract: Sr{sub 4−x}Ln{sub x}Mn(III){sub 2+x}Mn(IV){sub 1−x}O{sub 3}(GeO{sub 4}){sub 3}. Display Omitted - Highlights: • Double aliovalent substitution: Sr{sub 4}Mn{sub 3}O{sub 3}(GeO{sub 4}){sub 3} with respect to Na{sub 3}LnMn{sub 3}O{sub 3}(AsO{sub 4}){sub 3}. • Solid solution with respect to statistical disorder of Sr{sub 1

  20. Delivery of human NKG2D-IL-15 fusion gene by chitosan nanoparticles to enhance antitumor immunity

    SciTech Connect (OSTI)

    Yan, Chen; Jie, Leng; Yongqi, Wang; Weiming, Xiao; Juqun, Xi; Yanbing, Ding; Li, Qian; Xingyuan, Pan; Mingchun, Ji; Weijuan, Gong

    2015-07-31

    Nanoparticles are becoming promising carriers for gene delivery because of their high capacity in gene loading and low cell cytotoxicity. In this study, a chitosan-based nanoparticle encapsulated within a recombinant pcDNA3.1-dsNKG2D-IL-15 plasmid was generated. The fused dsNKG2D-IL-15 gene fragment consisted of double extracellular domains of NKG2D with IL-15 gene at downstream. The average diameter of the gene nanoparticles ranged from 200 nm to 400 nm, with mean zeta potential value of 53.8 ± 6.56 mV. The nanoparticles which were loaded with the dsNKG2D-IL-15 gene were uptaken by tumor cells with low cytotoxicity. Tumor cells pre-transfected by gene nanopartilces stimulated NK and T cells in vitro. Intramuscular injection of gene nanoparticles suppressed tumor growth and prolonged survival of tumor-bearing mice through activation of NK and CD8{sup +} T cells. Thus, chitosan-based nanoparticle delivery of dsNKG2D-IL-15 gene vaccine can be potentially used for tumor therapy. - Highlights: • Generation of a nanoparticle for delivery of dsNKG2D-IL-15 gene. • Characterization of the gene nanoparticle. • Antitumor activity mediated by the gene nanoparticle.

  1. Comparison of LiMnPO4 made by Combustion and Hydrothermal Syntheses

    SciTech Connect (OSTI)

    Chen, Jiajun; Doeff, Marca M.; Wang, Ruigang

    2008-05-15

    Among the olivine-structured metal phosphate family, LiMnPO{sub 4} exhibits a high discharge potential (4V), which is still compatible with common electrolytes, making it interesting for use in the next generation of Li ion batteries. The extremely low electronic conductivity of this material severely limits its electrochemical performance, however. One strategy to overcome this limitation is to make LiMnPO{sub 4} nanoparticulate to decrease the diffusion distance. Another is to add a carbon or other conductive coating in intimate contact with the nanoparticles of the main phase, as is commonly done with LiFePO{sub 4}. The electrochemical performance of LiFePO{sub 4} is highly dependent on the quality of the carbon coatings on the particles [1-2], among other variables. Combustion synthesis allows the co-synthesis of nanoparticles coated with carbon in one step. Hydrothermal synthesis is used industrially to make LiFePO{sub 4} cathode materials [3] and affords a good deal of control over purity, crystallinity, and particle size. A wide range of olivine-structured materials has been successfully prepared by this technique [4], including LiMnPO{sub 4} in this study. In this paper, we report on the new synthesis of nano-LiMnPO{sub 4} by a combustion method. The purity is dependent upon the conditions used for synthesis, including the type of fuel and precursors that are chosen. The fuel to nitrate ratio influences the combustion temperature, which determines the type and amount of carbon found in the LiMnPO{sub 4} composites. This can further be modified by use of carbon structural modifiers added during a subsequent (optional) calcination step. Figure 1 shows a transmission electron microscopy (TEM) image of the spherical nano-sized LiMnPO{sub 4} particles typically formed by combustion synthesis. The average particle size is around 30 nm, in agreement with values obtained by the Rietveld refinement of XRD patterns. The small size of the particles cause the peak

  2. Comparison of LiMnPO4 made by Combustion and Hydrothermal Syntheses

    SciTech Connect (OSTI)

    Chen, Jiajun; Doeff, Marca M.; Wang, Ruigang

    2008-10-12

    Among the olivine-structured metal phosphate family, LiMnPO{sub 4} exhibits a high discharge potential (4V), which is still compatible with common electrolytes, making it interesting for use in the next generation of Li ion batteries. The extremely low electronic conductivity of this material severely limits its electrochemical performance, however. One strategy to overcome this limitation is to make LiMnPO{sub 4} nanoparticulate to decrease the diffusion distance. Another is to add a carbon or other conductive coating in intimate contact with the nanoparticles of the main phase, as is commonly done with LiFePO{sub 4}. The electrochemical performance of LiFePO{sub 4} is highly dependent on the quality of the carbon coatings on the particles, among other variables. Combustion synthesis allows the co-synthesis of nanoparticles coated with carbon in one step. Hydrothermal synthesis is used industrially to make LiFePO{sub 4} cathode materials and affords a good deal of control over purity, crystallinity, and particle size. A wide range of olivine-structured materials has been successfully prepared by this technique, including LiMnPO{sub 4} in this study. In this paper, we report on the new synthesis of nano-LiMnPO{sub 4} by a combustion method. The purity is dependent upon the conditions used for synthesis, including the type of fuel and precursors that are chosen. The fuel to nitrate ratio influences the combustion temperature, which determines the type and amount of carbon found in the LiMnPO{sub 4} composites. This can further be modified by use of carbon structural modifiers added during a subsequent (optional) calcination step. Figure 1 shows a transmission electron microscopy (TEM) image of the spherical nano-sized LiMnPO{sub 4} particles typically formed by combustion synthesis. The average particle size is around 30 nm, in agreement with values obtained by the Rietveld refinement of XRD patterns. The small size of the particles cause the peak broadening evident

  3. Disorder dependent half-metallicity in Mn{sub 2}CoSi inverse Heusler alloy

    SciTech Connect (OSTI)

    Singh, Mukhtiyar; Saini, Hardev S.; Thakur, Jyoti; Reshak, Ali H.; Kashyap, Manish K.

    2013-12-15

    Heusler alloys based thin-films often exhibit a degree of atomic disorder which leads to the lowering of spin polarization in spintronic devices. We present ab-initio calculations of atomic disorder effects on spin polarization and half-metallicity of Mn{sub 2}CoSi inverse Heusler alloy. The five types of disorder in Mn{sub 2}CoSi have been proposed and investigated in detail. The A2{sub a}-type and B2-type disorders destroy the half-metallicity whereas it sustains for all disorders concentrations in DO{sub 3a}- and A2{sub b}-type disorder and for smallest disorder concentration studied in DO{sub 3b}-type disorder. Lower formation energy/atom for A2{sub b}-type disorder than other four disorders in Mn{sub 2}CoSi advocates the stability of this disorder. The total magnetic moment shows a strong dependence on the disorder and the change in chemical environment. The 100% spin polarization even in the presence of disorders explicitly supports that these disorders shall not hinder the use of Mn{sub 2}CoSi inverse Heusler alloy in device applications. - Graphical abstract: Minority-spin gap (E{sub g↓}) and HM gap (E{sub sf}) as a function of concentrations of various possible disorder in Mn{sub 2}CoSi inverse Heusler alloy. The squares with solid line (black color)/dotted line (blue color)/dashed line (red color) reperesents E{sub g↓} for DO{sub 3a}-/DO{sub 3b}-/A2{sub b}-type disorder in Mn{sub 2}CoSi and the spheres with solid line (black color)/dottedline (blue color)/dashed line (red color) represents E{sub sf} for DO{sub 3a}-/DO{sub 3b}-/A2{sub b}-type disorder in Mn{sub 2}CoSi. - Highlights: • The DO{sub 3}- and A2-type disorders do not affect the half-metallicity in Mn{sub 2}CoSi. • The B2-type disorder solely destroys half-metallicity in Mn{sub 2}CoSi. • The A2-type disorder most probable to occur out of all three types. • The total spin magnetic moment strongly depends on the disorder concentrations.

  4. Novel Solar Energy Conversion Materials by Design of Mn(II) Oxides

    SciTech Connect (OSTI)

    Lany, S.; Peng, H.; Ndione, P.; Zakutayev, A.; Ginley, D. S.

    2013-01-01

    Solar energy conversion materials need to fulfill simultaneously a number of requirements in regard of their band-structure, optical properties, carrier transport, and doping. Despite their desirable chemical properties, e.g., for photo-electrocatalysis, transition-metal oxides usually do not have desirable semiconducting properties. Instead, oxides with open cation d-shells are typically Mott or charge-transfer insulators with notoriously poor transport properties, resulting from large effective electron/hole masses or from carrier self-trapping. Based on the notion that the electronic structure features (p-d interaction) supporting the p-type conductivity in d10 oxides like Cu2O and CuAlO2 occurs in a similar fashion also in the d5 (high-spin) oxides, we recently studied theoretically the band-structure and transport properties of the prototypical binary d5 oxides MnO and Fe2O3 [PRB 85, 201202(R)]. We found that MnO tends to self-trap holes by forming Mn+III, whereas Fe2O3 self-traps electrons by forming Fe+II. However, the self-trapping of holes is suppressed by when Mn is tetrahedrally coordinated, which suggests specific routes to design novel solar conversion materials by considering ternary Mn(II) oxides or oxide alloys. We are presenting theory, synthesis, and initial characterization for these novel energy materials.

  5. Magnetic susceptibilities of liquid Cr-Au, Mn-Au and Fe-Au alloys

    SciTech Connect (OSTI)

    Ohno, S.; Shimakura, H.; Tahara, S.; Okada, T.

    2015-08-17

    The magnetic susceptibility of liquid Cr-Au, Mn-Au, Fe-Au and Cu-Au alloys was investigated as a function of temperature and composition. Liquid Cr{sub 1-c}Au{sub c} with 0.5 ≤ c and Mn{sub 1-c}Au{sub c} with 0.3≤c obeyed the Curie-Weiss law with regard to their dependence of χ on temperature. The magnetic susceptibilities of liquid Fe-Au alloys also exhibited Curie-Weiss behavior with a reasonable value for the effective number of Bohr magneton. On the Au-rich side, the composition dependence of χ for liquid TM-Au (TM=Cr, Mn, Fe) alloys increased rapidly with increasing TM content, respectively. Additionally, the composition dependences of χ for liquid Cr-Au, Mn-Au, and Fe-Au alloys had maxima at compositions of 50 at% Cr, 70 at% Mn, and 85 at% Fe, respectively. We compared the composition dependences of χ{sub 3d} due to 3d electrons for liquid binary TM-M (M=Au, Al, Si, Sb), and investigated the relationship between χ{sub 3d} and E{sub F} in liquid binary TM-M alloys at a composition of 50 at% TM.

  6. Extended magnetic exchange interactions in the high-temperature ferromagnet MnBi

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

    Christianson, Andrew D.; Hahn, Steven E.; Fishman, Randy Scott; Parker, David S.; McGuire, Michael A.; Sales, Brian C.; Lumsden, Mark D.; Williams, T. J.; Taylor, A. E.

    2016-05-09

    Here, the high-temperature ferromagnet MnBi continues to receive attention as a candidate to replace rare-earth-containing permanent magnets in applications above room temperature. This is due to a high Curie temperature, large magnetic moments, and a coercivity that increases with temperature. The synthesis of MnBi also allows for crystals that are free of interstitial Mn, enabling more direct access to the key interactions underlying the physical properties of binary Mn-based ferromagnets. In this work, we use inelastic neutron scattering to measure the spin waves of MnBi in order to characterize the magnetic exchange at low temperature. Consistent with the spin reorientationmore » that occurs below 140~K, we do not observe a spin gap in this system above our experimental resolution. A Heisenberg model was fit to the spin wave data in order to characterize the long-range nature of the exchange. It was found that interactions up to sixth nearest neighbor are required to fully parameterize the spin waves. Surprisingly, the nearest-neighbor term is antiferromagnetic, and the realization of a ferromagnetic ground state relies on the more numerous ferromagnetic terms beyond nearest neighbor, suggesting that the ferromagnetic ground state arises as a consequence of the long-ranged interactions in the system.« less

  7. High-Resolution Structure of the Photosynthetic Mn4Ca Catalyst from X-ray Spectroscopy

    SciTech Connect (OSTI)

    Yachandra, Vittal; Yano, Junko; Kern, Jan; Pushkar, Yulia; Sauer, Kenneth; Glatzel, Pieter; Bergmann, Uwe; Messinger, Johannes; Zouni, Athina; Yachandra, Vittal K.

    2007-08-01

    The application of high-resolution X-ray spectroscopy methods to study the photosynthetic water oxidizing complex, which contains a unique hetero-nuclear catalytic Mn4Ca cluster, are described. Issues of X-ray damage especially at the metal sites in the Mn4Ca cluster are discussed. The structure of the Mn4Ca catalyst at high-resolution which has so far eluded attempts of determination by X-ray diffraction, EXAFS and other spectroscopic techniques has been addressed using polarized EXAFS techniques applied to oriented PS II membrane preparations and PS II single crystals. A review of how the resolution of traditional EXAFS techniques can be improved, using methods such as range-extended EXAFS is presented, and the changes that occur in the structure of the cluster as it advances through the catalytic cycle are described. X-ray absorption and emission techniques (XANES and K? emission) have been used earlier to determine the oxidation states of the Mn4Ca cluster, and in this report we review the use of X-ray resonant Raman spectroscopy to understand the electronic structure of the Mn4Ca cluster as it cycles through the intermediate S-states.

  8. Electronic structure and the origin of the Dzyaloshinskii-Moriya interaction in MnSi

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

    Satpathy, S.; Shanavas, K. V.

    2016-05-02

    Here, the metallic helimagnet MnSi has been found to exhibit skyrmionic spin textures when subjected to magnetic fields at low temperatures. The Dzyaloshinskii-Moriya (DM) interaction plays a key role in stabilizing the skyrmion state. With the help of first-principles calculations, crystal field theory and a tight-binding model we study the electronic structure and the origin of the DM interaction in the B20 phase of MnSi. The strength ofmore » $$\\vec{D}$$ parameter is determined by the magnitude of the spin-orbit interaction and the degree of orbital mixing, induced by the symmetry-breaking distortions in the B20 phase. We find that, strong coupling between Mn-$d$ and Si-$p$ states lead to a mixed valence ground state $$|d^{7-x}p^{2+x}\\rangle$$ configuration. The experimental magnetic moment of $$0.4~\\mu_B$$ is consistent with the Coulomb-corrected DFT+$U$ calculations, which redistributes electrons between the majority and minority spin channels. We derive the magnetic interaction parameters $J$ and $$\\vec{D}$$ for Mn-Si-Mn superexchange paths using Moriya's theory assuming the interaction to be mediated by $e_g$ electrons near the Fermi level. Using parameters from our calculations, we get reasonable agreement with the observations.« less

  9. DFPARThIl!NT OF ENERGY EERE PROJECT MANAGEMENT CENTER NEPA DETERlIfiNATION

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

    s DFPARThIl!NT OF ENERGY EERE PROJECT MANAGEMENT CENTER NEPA DETERlIfiNATION Page 1 of3 RECIPIENT :State of Hawaii DBEOT STATE : HI PROJECf TITLE: Loan Loss Reserve Funding Opportunity Announc~ment Number DE-FOA-0000052 Procurement Inslrument Number DE-EEOOOO216 NEPA Control Number em Number GF0-0000216-001 GO Based on my review ofthe informalion concerning the proposed aClion, as NEPA Compliance Officer (authorized under DOE Order 451.1A), I have made the following determination: ex, EA, EIS

  10. Elasticity and magnetocaloric effect in MnFe4Si3

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

    Herlitschke, Marcus; Klobes, B.; Sergueev, I.; Hering, Paul; Persson, Joerg; Hermann, Raphael P.

    2016-03-16

    The room temperature magnetocaloric material MnFe4Si3 was investigated with nuclear inelastic scattering (NIS) and resonant ultrasound spectroscopy (RUS) at different temperatures and applied magnetic fields in order to assess the infuence of the magnetic transition and the magnetocaloric effect on the lattice dynamics. The NIS data give access to phonons with energies above 3 meV, whereas RUS probes the elasticity of the material in the MHz frequency range and thus low energy, ~5 neV, phonon modes. A significant infuence of the magnetic transition on the lattice dynamics is observed only in the low energy region. Here, MnFe4Si3 and other compoundsmore » in the Mn5-xFexSi3 series were also investigated with vibrating sample magnetometry, resistivity measurements and Moessbauer spectroscopy in order to study the magnetic transitions and to complement the obtained results on the lattice dynamics.« less

  11. Electronic structural and magnetic properties of Mn{sub 5}Ge{sub 3} clusters

    SciTech Connect (OSTI)

    Yuan, H. K.; Chen, H. Kuang, A. L.; Tian, C. L.; Wang, J. Z.

    2013-11-28

    Theoretical understanding of the stability, ferromagnetism, and spin polarization of Mn{sub 5}Ge{sub 3} clusters has been performed by using the density functional theory with generalized gradient approximation for exchange and correlation. The magnetic moments and magnetic anisotropy energy (MAE) have been calculated for both bulk and clusters, and the enhanced magnetic moment as well as the enlarged MAE have been identified in clusters. The most attractive achievement is that Mn{sub 5}Ge{sub 3} clusters show a fine half-metallic character with large energy scales. The present results may have important implications for potential applications of small Mn{sub 5}Ge{sub 3} clusters as both emerging spintronics and next-generation data-storage technologies.

  12. Theoretical study on the role of dynamics on the unusual magnetic properties in MnBi

    SciTech Connect (OSTI)

    Shanavas, K. V.; Parker, David; Singh, David J.

    2014-11-27

    Here we study the electronic structure and lattice dynamics in the ferromagnet MnBi using first-principles calculations and a tight-binding model. The band structure around the Fermi level is dominated by Bi-p states which are the primary contributors to the magnetic anisotropy energy in the low temperature structure. A tight-binding model consisting of Mn-d and Bi-p states is developed and the parameters are determined from first-principles calculations. Phonon dispersions and elastic moduli exhibit several interesting features. In conclusion, the results imply that the magnetic interaction with the crystal lattice in MnBi is considerably more complex than previously thought and in particular that there is a rich interplay between phonons and magnetism involving both magnetoelastic and magnetostrictive coupling.

  13. Theoretical study on the role of dynamics on the unusual magnetic properties in MnBi

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

    Shanavas, K. V.; Parker, David; Singh, David J.

    2014-11-27

    Here we study the electronic structure and lattice dynamics in the ferromagnet MnBi using first-principles calculations and a tight-binding model. The band structure around the Fermi level is dominated by Bi-p states which are the primary contributors to the magnetic anisotropy energy in the low temperature structure. A tight-binding model consisting of Mn-d and Bi-p states is developed and the parameters are determined from first-principles calculations. Phonon dispersions and elastic moduli exhibit several interesting features. In conclusion, the results imply that the magnetic interaction with the crystal lattice in MnBi is considerably more complex than previously thought and in particularmore » that there is a rich interplay between phonons and magnetism involving both magnetoelastic and magnetostrictive coupling.« less

  14. Anomalous magnetic configuration of Mn{sub 2}NiAl ribbon and the role of hybridization in the martensitic transformation of Mn{sub 50}Ni{sub 50−x}Al{sub x} ribbons

    SciTech Connect (OSTI)

    Zhao, R. B.; Zhao, D. W.; Li, G. K.; Ma, L. E-mail: houdenglu@mail.hebtu.edu.cn; Zhen, C. M.; Hou, D. L. E-mail: houdenglu@mail.hebtu.edu.cn; Wang, W. H.; Liu, E. K.; Chen, J. L.; Wu, G. H.

    2014-12-08

    The magnetic configuration of Mn{sub 2}NiAl ribbon has been investigated. In contrast to Ni{sub 2}MnAl, the compound Mn{sub 2}NiAl with considerable disorder does exhibit ferromagnetism and, due to exchange interaction competition, both ferromagnetic and antiferromagnetic moment orientations can coexist between nearest neighbor Mn atoms. This is unexpected in Heusler alloys. Regarding the mechanism of the martensitic transformation in Mn{sub 50}Ni{sub 50−x}Al{sub x}, it is found that increasing the Al content results in an unusual change in the lattice constant, a decrease of the transformation entropy change, and enhancement of the calculated electron localization. These results indicate that the p-d covalent hybridization between Mn (or Ni) and Al atoms gradually increases at the expense of the d-d hybridization between Ni and Mn atoms. This leads to an increased stability of the austenite phase and a decrease of the martensitic transformation temperature. For 11 ≤ x ≤ 14, Mn{sub 50}Ni{sub 50−x}Al{sub x} ferromagnetic shape memory alloys are obtained.

  15. Enhanced performance of branched TiO{sub 2} nanorod based Mn-doped CdS and Mn-doped CdSe quantum dot-sensitized solar cell

    SciTech Connect (OSTI)

    Kim, Soo-Kyoung; Gopi, Chandu V. V. M.; Lee, Jae-Cheol; Kim, Hee-Je

    2015-04-28

    TiO{sub 2} branched nanostructures could be efficient as photoanodes for quantum dot-sensitized solar cells (QDSCs) due to their large surface area for QD deposition. In this study, Mn-doped CdS/Mn-doped CdSe deposited branched TiO{sub 2} nanorods were fabricated to enhance the photovoltaic performance of QDSCs. Mn doping in CdS and CdSe retards the recombination losses of electrons, while branched TiO{sub 2} nanorods facilitate effective electron transport and compensate for the low surface area of the nanorod structure. As a result, the charge-transfer resistance (R{sub CT}), electron lifetime (?{sub e}), and the amount of QD deposition were significantly improved with branched TiO{sub 2} nanorod based Mn-doped CdS/Mn-doped CdSe quantum dot-sensitized solar cell.

  16. Fabrication of (Mn,Co)3O4 Surface Coatings onto Alloy Substrates

    SciTech Connect (OSTI)

    Yang, Zhenguo; Xia, Guanguang; Li, Xiaohong S.; Singh, Prabhakar; Stevenson, Jeffry W.

    2007-04-30

    Ferritic stainless steels are promising candidates for IT-SOFC interconnect applications due to their low cost and resistance to oxidation at SOFC operating temperatures. However, several challenges remain, including long term electrical conductivity and surface stability under interconnect exposure conditions and chromia scale evaporation. One means of extending interconnect lifetime and improving performance is to apply a protective coating, such as (Mn,Co)3O4 spinel, to the cathode side of the interconnect. These coatings have proven effective in reducing scale growth kinetics and Cr volatility. This report describes several procedures developed at PNNL for fabricating (Mn,Co)3O4 spinel coatings onto ferritic stainless steels.

  17. Unoccupied electronic structure of Ni2MnGa ferromagnetic shape memory alloy

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

    Maniraj, M.; D׳Souza, S. W.; Rai, Abhishek; Schlagel, D. L.; Lograsso, T. A.; Iowa State Univ., Ames, IA; Chakrabarti, Aparna; Barman, S. R.

    2015-08-20

    Momentum resolved inverse photoemission spectroscopy measurements show that the dispersion of the unoccupied bands of Ni2MnGa is significant in the austenite phase. Furthermore, in the martensite phase, it is markedly reduced, which is possibly related to the structural transition to an incommensurate modulated state in the martensite phase. Finally, based on the first principle calculations of the electronic structure of Ni–Mn–Ga, we show that the modification of the spectral shape with surface composition is related to change in the hybridization between the Mn 3d and Ni 3d-like states that dominate the unoccupied conduction band.

  18. Study of lattice dynamics in yttrium doped NdMnO{sub 3} using Raman spectroscopy

    SciTech Connect (OSTI)

    Yadav, Ruchika Elizabeth, Suja; Nair, Harikrishnan S.

    2014-04-24

    A systematic study of Raman spectra on Yttrium doped NdMnO{sub 3} polycrystalline samples was undertaken to understand the lattice dynamics in this compound. Raman active phonons were analyzed and the observed peak were assigned to elucidate various phonon modes in the range (200 - 800) cm{sup −1}. It was observed that at 325 cm{sup −1} phonon frequency shifts upward as much as upto 4 % with increase in Yttrium content. Lattice distortions manifest themselves by frequency shifts in both bending and tilt modes of MnO{sub 6} octahedra, resulting in increase of Raman band line-widths.

  19. Antiferromagentic resonance detected by direct current voltages in MnF{sub 2}/Pt bilayers

    SciTech Connect (OSTI)

    Ross, Philipp; Schreier, Michael Lotze, Johannes; Huebl, Hans; Goennenwein, Sebastian T. B.; Gross, Rudolf

    2015-12-21

    We performed coplanar waveguide-based broadband ferromagnetic resonance experiments on the antiferromagnetic insulator MnF{sub 2}, while simultaneously recording the DC voltage arising in a thin platinum film deposited onto the MnF{sub 2}. The antiferromagnetic resonance is clearly reflected in both the transmission through the waveguide as well as the DC voltage in the Pt strip. The DC voltage remains largely unaffected by field reversal and thus presumably stems from microwave rectification and/or heating effects. However, we identify a small magnetic field orientation dependent contribution, compatible with antiferromagnetic spin pumping theory.

  20. Graphene in proximity to magnetic insulating LaMnO{sub 3}

    SciTech Connect (OSTI)

    Cheng, Guanghui; Wei, Laiming, E-mail: laiming@ustc.edu.cn, E-mail: cgzeng@ustc.edu.cn; Cheng, Long; Liang, Haixing; Zhang, Xiaoqiang; Li, Hui [Hefei National Laboratory for Physical Sciences at the Microscale (HFNL) and Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China); Yu, Guolin [Shanghai Institute of Technical Physics, Chinese Academy of Science, Shanghai 200083 (China); Zeng, Changgan, E-mail: laiming@ustc.edu.cn, E-mail: cgzeng@ustc.edu.cn [Hefei National Laboratory for Physical Sciences at the Microscale (HFNL) and Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China); International Center for Quantum Design of Functional Materials (ICQD), HFNL, University of Science and Technology of China, Hefei, Anhui 230026 (China); Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China)

    2014-09-29

    Proximity to functional substrates may enhance the coupling between the quantum degrees of freedom and thus develop nontrivial quantum effects in graphene. Here, we demonstrate the successful fabrication of graphene in proximity to atomically flat magnetic insulating LaMnO{sub 3} films. The insulating nature of the LaMnO{sub 3} films not only ensures the electronic transport only occur in the graphene layers but also allow them to serve as dielectric layers for gating. Transport measurements reveal anomalous behaviors, including asymmetrical longitudinal magnetoresistivity and nonlinear Hall effect. This work may pave a way toward the realization of intriguing quantum phases in graphene.

  1. Electron-hole asymmetry, Dirac fermions, and quantum magnetoresistance in BaMnBi2

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

    Li, Lijun; Wang, Kefeng; Graf, D.; Wang, Limin; Wang, Aifeng; Petrovic, C.

    2016-03-28

    Here, we report two-dimensional quantum transport and Dirac fermions in BaMnBi2 single crystals. BaMnBi2 is a layered bad metal with highly anisotropic conductivity and magnetic order below 290 K. Magnetotransport properties, nonzero Berry phase, small cyclotron mass, and the first-principles band structure calculations indicate the presence of Dirac fermions in Bi square nets. Quantum oscillations in the Hall channel suggest the presence of both electron and hole pockets, whereas Dirac and parabolic states coexist at the Fermi level.

  2. Orbital two-channel Kondo effect in epitaxial ferromagnetic L10-MnAl films

    Office of Scientific and Technical Information (OSTI)

    (Journal Article) | SciTech Connect Journal Article: Orbital two-channel Kondo effect in epitaxial ferromagnetic L10-MnAl films Citation Details In-Document Search Title: Orbital two-channel Kondo effect in epitaxial ferromagnetic L10-MnAl films The orbital two-channel Kondo effect displaying exotic non-Fermi liquid behaviour arises in the intricate scenario of two conduction electrons compensating a pseudo-spin-1/2 impurity of two-level system. Despite extensive efforts for several decades,

  3. Structural transformations in Mn{sub 2}NiGa due to residual stress

    SciTech Connect (OSTI)

    Singh, Sanjay; Maniraj, M.; D'Souza, S. W.; Barman, S. R.; Ranjan, R.

    2010-02-22

    Powder x-ray diffraction study of Mn{sub 2}NiGa ferromagnetic shape memory alloy shows the existence of a 7M monoclinic modulated structure at room temperature (RT). The structure of Mn{sub 2}NiGa is found to be highly dependent on residual stress. For higher stress, the structure is tetragonal at RT, and for intermediate stress it is 7M monoclinic. However, only when the stress is considerably relaxed, the structure is cubic, as is expected at RT since the martensitic transition temperature is 230 K.

  4. MnO spin-wave dispersion curves from neutron powder diffraction

    SciTech Connect (OSTI)

    Goodwin, Andrew L.; Dove, Martin T.; Tucker, Matthew G.; Keen, David A.

    2007-02-15

    We describe a model-independent approach for the extraction of spin-wave dispersion curves from powder neutron total scattering data. Our approach is based on a statistical analysis of real-space spin configurations to calculate spin-dynamical quantities. The RMCPROFILE implementation of the reverse Monte Carlo refinement process is used to generate a large ensemble of supercell spin configurations from MnO powder diffraction data collected at 100 K. Our analysis of these configurations gives spin-wave dispersion curves for MnO that agree well with those determined independently using neutron triple-axis spectroscopic techniques.

  5. Study of structural and electronic properties of Mn{sub 3}O{sub 4}

    SciTech Connect (OSTI)

    Kaur, Ramandeep Maitra, Tulika Nautiyal, Tashi

    2014-04-24

    Using density functional theory calculations we have examined the structural and electronic properties of magnetic spinel Mn{sub 3}O{sub 4}. We have optimized the structure (both volume and c/a ratio) within GGA. Then Coulomb correlations are included in the calculations to study the electronic properties. We observe that both the band gap and magnetic moment increase with the increase in Coulomb correlation due to the increased Jahn-Teller splitting and localization of the single e{sub g} electron of Mn{sup 3+}.

  6. Perpendicularly magnetized {tau}-MnAl (001) thin films epitaxied on GaAs

    SciTech Connect (OSTI)

    Nie, S. H.; Zhu, L. J.; Lu, J.; Pan, D.; Wang, H. L.; Yu, X. Z.; Xiao, J. X.; Zhao, J. H.

    2013-04-15

    Perpendicularly magnetized {tau}-MnAl films have been epitaxied on GaAs (001) by molecular-beam epitaxy. Crystalline quality and magnetic properties of the samples were strongly dependent on growth temperature. The highest coercivity of 10.7 kOe, saturation magnetization of 361.4 emu/cm{sup 3}, perpendicular magnetic anisotropy constant of 13.65 Merg/cm{sup 3}, and magnetic energy product of 4.44 MGOe were achieved. These tunable magnetic properties make MnAl films valuable as excellent and cost-effective alternative for not only high density perpendicular magnetic recording storage and spintronics devices but also permanent magnets.

  7. Modeling and Characterization of the Magnetocaloric Effect in Ni2MnGa Materials

    SciTech Connect (OSTI)

    Nicholson, Don M; Odbadrakh, Khorgolkhuu; Shassere, Benjamin; Rios, Orlando; Hodges, Jason P; Ludtka, Gerard Michael; Porter, Wallace D; Safa-Sefat, Athena; Rusanu, Aurelian; Brown, Greg; Evans III, Boyd Mccutchen

    2014-01-01

    Magnetic shape memory alloys have great promise as magneto-caloric effect refrigerant materials due to their combined magnetic and structural transitions. Computational and experimental research is reported on the Ni2MnGa material system. The magnetic states of this system are explored using the Wang-Landau statistical approach in conjunction with the Locally Self-consistent Multiple-Scattering method. The effects of alloying agents on the transition temperatures of the Ni2MnGa alloy are investigated using differential scanning calorimetry and superconducting quantum interference device. Experiments are performed at the Spallation Neutron Source at Oak Ridge National Laboratory to observe the structural and magnetic phase transformations.

  8. Enlarged Mn 3s splitting and room-temperature ferromagnetism in epitaxially grown oxygen doped Mn{sub 2}N{sub 0.86} films

    SciTech Connect (OSTI)

    Meng, M.; Wu, S. X. Ren, L. Z.; Zhou, W. Q.; Wang, Y. J.; Wang, G. L.; Li, S. W.

    2014-11-07

    Single-phase and oxygen doped Mn{sub 2}N{sub 0.86} thin films have been grown on MgO (111) by plasma-assisted molecular beam epitaxy. The films grow under tensile strain and, remarkably, they show ferromagnetic-like interactions at low temperature and ferromagnetic ordering agreed well with the Bloch-law T{sup 3/2} at room-temperature. We further demonstrate the enlarged Mn 3s splitting (6.46 eV) and its possible relation to the observed ferromagnetism. Our study not only provide a strategy for further theoretical work on oxygen doped manganese nitrides, but also shed promising light on utilizing its room-temperature FM property to fabricate spintronic devices.

  9. Synthesis of MnO{sub 2}-graphene composites with enhanced supercapacitive performance via pulse electrodeposition under supergravity field

    SciTech Connect (OSTI)

    Liu, Tingting; Shao, Guangjie; Ji, Mingtong; Wang, Guiling

    2014-07-01

    A method of pulse electrodeposition under supergravity field was proposed to synthesize MnO{sub 2}-graphene composites. Supergravity is very efficient for promoting mass transfer and decreasing concentration polarization during the electrodeposition process. The synthesis was conducted on our homemade supergravity equipment. The strength of supergravity field depended on the rotating speed of the ring electrode. 3D flower like MnO{sub 2} spheres composed of nanoflakes were acquired when the rotating speed was 3000 rpm. Graphene nanosheets play as a role of conductive substrates for MnO{sub 2} growing. The composites are evaluated as electrode materials for supercapacitors. Electrochemical results show that the maximum specific capacitance of the MnO{sub 2}-graphene composite is 595.7 F g{sup ?1} at a current density of 0.5 A g{sup ?1}. In addition, the composite exhibits excellent cycle stability with no capacitance attenuation after 1000 cycles. The approach provides new ideas for developing supercapacitor electrode materials with high performance. - Graphical abstract: 3D flower like MnO{sub 2} spheres composed of nanoflakes were acquired at 3000 rpm. - Highlights: MnO{sub 2}-graphene composites were prepared by pulse electrodeposition under supergravity. 3D flower like MnO{sub 2} spheres are anchored on the graphene nanosheets. The MnO{sub 2}-graphene electrode exhibits a specific capacitance of 595.7 F g{sup ?1}.

  10. Growth of single-crystal {alpha}-MnO{sub 2} nanorods on multi-walled carbon nanotubes

    SciTech Connect (OSTI)

    Chen Yong; Liu Chenguang; Liu Chang; Lu Gaoqing; Cheng Huiming

    2007-11-06

    Single-crystal {alpha}-MnO{sub 2} nanorods were grown on multi-walled carbon nanotubes (MWNTs) in H{sub 2}SO{sub 4} aqueous solution. The morphology and microstructure of the composites were examined by transmission electron microscopy, high-resolution transmission electron microscopy (HRTEM), X-ray diffractometry and energy dispersive spectroscopy (EDS). The results show that {alpha}-MnO{sub 2} single-crystal nanorods with a mean diameter of 15 nm were densely grown on the surface of MWNTs. Those MWNTs/MnO{sub 2} composites were used as an electrode material for supercapacitors, and it was found that the supercapacitor performance using MWNTs/MnO{sub 2} composites was improved largely compared to that using pure MWNTs and {alpha}-MnO{sub 2} nanorod mechanically mixed with MWNTs.

  11. Low frequency sonochemical synthesis of nanoporous amorphous manganese dioxide (MnO{sub 2}) and adsorption of remazol reactive dye

    SciTech Connect (OSTI)

    Hasan, Siti Zubaidah; Yusop, Muhammad Rahimi; Othman, Mohamed Rozali

    2015-09-25

    Nanoporous amorphous-MnO{sub 2} was synthesized by sonochemical process (sonication) on the solid manganese (II) acetate tetrahydrate (Mn(CH{sub 3}COO){sub 2}.4H{sub 2}O) in 0.1 M KMnO{sub 4}. The product was characterized by X-ray diffraction (XRD), morphology of the material was scanned by Field Emission Scanning Electron Microscopy (FE-SEM) and absorptions of MnO{sub 2} bonding was characterized by Fourier Transform Infra-Red Spectrometer (FT-IR). Remazol reactive dye or Red 3BS, was used in the adsorption study using nanoporous amorphous-MnO{sub 2}. In batch experiment, 10 ppm of Remazol reactive dye was used and experiment was carried out at room temperature. Adsorption of Remazol dye on 0.2g synthesized nanoporous amorphous-MnO{sub 2} showed 99 – 100% decolorization.

  12. Observation of Precipitation Evolution in Fe-Ni-Mn-Ti-Al Maraging Steel using Atom Probe Tomography

    SciTech Connect (OSTI)

    Pereloma, E. V.; Stohr, R A; Miller, Michael K; Ringer, S. P.

    2009-01-01

    We describe the full decomposition sequence in an Fe-Ni-Mn-Ti-Al maraging steel during isothermal annealing at 550 C. Following significant pre-precipitation clustering reactions within the supersaturated martensitic solid solution, (Ni,Fe){sub 3}Ti and (Ni,Fe){sub 3}(Al,Mn) precipitates eventually form after isothermal aging for {approx}60 seconds. The morphology of the (Ni,Fe){sub 3}Ti particles changes gradually during aging from predominantly plate-like to rod-like, and, importantly, Mn and Al were observed to segregate to these precipitate/matrix interfaces. The (Ni,Fe){sub 3}(Al,Mn) precipitates occurred at two main locations: uniformly within the matrix and at the periphery of the (Ni,Fe){sub 3}Ti particles. We relate this latter mode of precipitation to the Mn-Al segregation.

  13. X-ray absorption spectroscopy of Mn doped ZnO thin films prepared by rf sputtering technique

    SciTech Connect (OSTI)

    Yadav, Ashok Kumar; Jha, S. N.; Bhattacharyya, D.; Haque, Sk Maidul; Shukla, Dinesh; Choudhary, Ram Janay

    2015-11-15

    A set of r.f. sputter deposited ZnO thin films prepared with different Mn doping concentrations have been characterised by Extended X-ray Absorption Fine Structure (EXAFS) and X-ray Absorption Near Edge Spectroscopy (XANES) measurements at Zn, Mn and O K edges and at Mn L{sub 2,3} edges apart from long range structural characterisation by Grazing Incident X-ray Diffraction (GIXRD) technique. Magnetic measurements show room temperature ferromagnetism in samples with lower Mn doping which is however, gets destroyed at higher Mn doping concentration. The results of the magnetic measurements have been explained using the local structure information obtained from EXAFS and XANES measurements.

  14. Microstructures and Mechanical Properties of Compositionally Complex Co-free FeNiMnCr18 FCC Solid Solution Alloy

    SciTech Connect (OSTI)

    Wu, Zhenggang; Bei, Hongbin

    2015-01-01

    Recently,a structurally-simplebutcompositionally-complex FeNiCoMnCr highentropyalloywasfoundto haveexcellentmechanicalproperties(e.g.,highstrengthandductility).Tounderstandthepotentialof using highentropyalloysasstructuralmaterialsforadvancednuclearreactorandpowerplants,itis necessary tohaveathoroughunderstandingoftheirstructuralstabilityandmechanicalpropertiesde- gradation underneutronirradiation.ThisrequiresustodevelopasimilarmodelalloywithoutCobe- cause materialwithCowillmakepost-neutron-irradiationtestingdifficult duetotheproductionofthe 60Co radioisotope.Toachievethisgoal,aFCC-structuredsingle-phasealloywithacompositionof FeNiMnCr18 wassuccessfullydeveloped.Thisnear-equiatomicFeNiMnCr18 alloy hasgoodmalleability and itsmicrostructurecanbecontrolledbythermomechanicalprocessing.Byrollingandannealing,the as-cast elongated-grained-microstructureisreplacedbyhomogeneousequiaxedgrains.Themechanical properties (e.g.,strengthandductility)oftheFeNiMnCr18 alloy arecomparabletothoseoftheequiatomic FeNiCoMnCr highentropyalloy.Bothstrengthandductilityincreasewithdecreasingdeformation temperature,withthelargestdifferenceoccurringbetween293and77K.Extensivetwin-bandswhich are bundlesofnumerousindividualtwinsareobservedwhenitistensile-fracturedat77K.Notwin bands aredetectedbyEBSDformaterialsdeformedat293Kandhigher.Theunusualtemperature-de- pendencies ofUTSanduniformelongationcouldbecausedbythedevelopmentofthedensetwin substructure, twin-dislocationinteractionsandtheinteractionsbetweenprimaryandsecondarytwin- ning systemswhichresultinamicrostructurerefinement andhencecauseenhancedstrainhardening and postponednecking.

  15. MxMn8O16 (M = Ag or K) as promising cathode materials for secondary Mg based batteries: The role of the cation M

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

    Huang, Jianping; Takeuchi, Esther S.; Altug S. Poyraz; Takeuchi, Kenneth J.; Marschilok, Amy C.

    2016-02-15

    Here, AgxMn8O16 (Ag-OMS-2) and KxMn8O16 (K-OMS-2) were investigated as high voltage cathode materials for Mg based batteries. Both MxMn8O16 materials delivered high initial capacities (>180 mA h g–1), and KxMn8O16 showed high cycle stability with a reversible capacity of >170 mA h g–1 after 20 cycles.

  16. Bulk and surface half-metallicity: The case of D0{sub 3}-type Mn{sub 3}Ge

    SciTech Connect (OSTI)

    Liu, Hao; Gao, G. Y. Hu, Lei; Ni, Yun; Zu, Fengxia; Zhu, Sicong; Wang, Shuling; Yao, K. L.

    2014-01-21

    Motivated by the experimental realization of D0{sub 22}-type Mn{sub 3}Ge (001) films [Kurt et al. Appl. Phys. Lett. 101, 132410 (2012)] and the structural stability of D0{sub 3}-type Heusler alloy Mn{sub 3}Ge [Zhang et al. J. Phys.: Condens. Matter 25, 206006 (2013)], we use the first-principles calculations based on the full potential linearized augmented plane-wave method to investigate the electronic and magnetic properties of D0{sub 3}-type Heusler alloy Mn{sub 3}Ge and its (001) surface. We show that bulk D0{sub 3}-Mn{sub 3}Ge is a half-metallic ferromagnet with the minority-spin energy gap of 0.52 eV and the magnetic moment of 1.00 μ{sub B} per formula unit. The bulk half-metallicity is preserved at the pure Mn-terminated (001) surface due to the large exchange split, but the MnGe-terminated (001) surface destroys the bulk half-metallicity. We also reveal that the surface stabilities are comparable between the D0{sub 3}-Mn{sub 3}Ge (001) and the experimental D0{sub 22}-Mn{sub 3}Ge (001), which indicates the feasibility to grow the Mn{sub 3}Ge (001) films with D0{sub 3} phase other than D0{sub 22} one. The surface half-metallicity and stability make D0{sub 3}-Mn{sub 3}Ge a promising candidate for spintronic applications.

  17. Magnetochromic effect in multiferroic R In <mn>1mn> x Mn x O <mn>3mn> ( R = Tb , Dy)

    SciTech Connect (OSTI)

    Chen, P.; Holinsworth, B. S.; O'Neal, K. R.; Brinzari, T. V.; Mazumdar, D.; Topping, C. V.; Luo, X.; Cheong, S.-W.; Singleton, J.; McGill, S.; Musfeldt, J. L.

    2015-05-26

    We combined high field magnetization and magneto-optical spectroscopy to investigate spin-charge coupling in Mn-substituted rare-earth indium oxides of chemical formula RIn₁₋xMnxO₃ (R=Tb, Dy). The edge states, on-site Mn³⁺d to d excitations, and rare-earth f-manifold excitations all track the magnetization energy due to dominant Zeeman interactions. The field-induced modifications to the rare-earth excitations are quite large because spin-orbit coupling naturally mixes spin and charge, suggesting that the next logical step in the design strategy should be to bring spin-orbit coupling onto the trigonal bipyramidal chromophore site with a 4 or 5d center.

  18. Keratinocyte-derived IL-24 plays a role in the positive feedback regulation of epidermal inflammation in response to environmental and endogenous toxic stressors

    SciTech Connect (OSTI)

    Jin, Sun Hee; Choi, Dalwoong; Chun, Young-Jin; Noh, Minsoo

    2014-10-15

    Keratinocytes are the major cellular components of human epidermis and play a key role in the modulating cutaneous inflammation and toxic responses. In human chronic skin diseases, the common skin inflammatory phenotypes like skin barrier disruption and epidermal hyperplasia are manifested in epidermal keratinocytes by interactions with T helper (Th) cells. To find a common gene expression signature of human keratinocytes in chronic skin diseases, we performed a whole genome microarray analysis on normal human epidermal keratinocytes (NHKs) treated with IFNγ, IL-4, IL-17A or IL-22, major cytokines from Th1, Th2, Th17 or Th22 cells, respectively. The microarray results showed that the four genes, IL-24, PDZK1IP1, H19 and filaggrin, had common expression profiles in NHKs exposed to Th cell cytokines. In addition, the acute phase pro-inflammatory cytokines, IL-1β, IL-6 and TNFα, also change the gene transcriptional profile of IL-24, PDZK1IP1, H19, and filaggrin in NHKs as those of Th cytokines. Therefore, the signature gene set, consisting of IL-24, PDZK1IP1, H19, and filaggrin, provides essential insights for understanding the process of cutaneous inflammation and toxic responses. We demonstrate that environmental toxic stressors, such as chemical irritants and ultraviolet irradiation stimulate the production of IL-24 in NHKs. IL-24 stimulates the JAK1-STAT3 and MAPK pathways in NHKs, and promotes the secretion of pro-inflammatory mediators IL-8, PGE2, and MMP-1. These results suggest that keratinocyte-derived IL-24 participates in the positive feedback regulation of epidermal inflammation in response to both endogenous and environmental toxic stressors. - Highlights: • Cutaneous inflammatory gene signature consists of PDZK1IP1, IL-24, H19 and filaggrin. • Pro-inflammatory cytokines increase IL-24 production in human keratinocytes. • Environmental toxic stressors increase IL-24 production in human keratinocytes. • IL-24 stimulates human keratinocytes to

  19. Redox Dynamics of Mixed Metal (Mn, Cr, and Fe) Ultrafine Particles

    SciTech Connect (OSTI)

    Nico, Peter S.; Kumfer, Benjamin M.; Kennedy, Ian M.; Anastasio, Cort

    2008-08-01

    The impact of particle composition on metal oxidation state, and on changes in oxidation state with simulated atmospheric aging, are investigated experimentally in flame-generated nanoparticles containing Mn, Cr, and Fe. The results demonstrate that the initial fraction of Cr(VI) within the particles decreases with increasing total metal concentration in the flame. In contrast, the initial Mn oxidation state was only partly controlled by metal loading, suggesting the importance of other factors. Two reaction pathways, one reductive and one oxidative, were found to be operating simultaneously during simulated atmospheric aging. The oxidative pathway depended upon the presence of simulated sunlight and O{sub 3}, whereas the reductive pathway occurred in the presence of simulated sunlight alone. The reductive pathway appears to be rapid but transient, allowing the oxidative pathway to dominate with longer aging times, i.e. greater than {approx}8 hours. The presence of Mn within the particles enhanced the importance of the oxidative pathway, leading to more net Cr oxidation during aging implying that Mn can mediate oxidation by removal of electrons from other particulate metals.

  20. Short- and long-range magnetic order in LaMnAsO

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

    McGuire, Michael A.; Garlea, Vasile Ovidiu

    2016-02-02

    The magnetic properties of the layered oxypnictide LaMnAsO have been revisited using neutron scattering and magnetization measurements. The present measurements identify the Néel temperature TN = 360(1) K. Below TN the critical exponent describing the magnetic order parameter is β=0.33–0.35 , consistent with a three-dimensional Heisenberg model. Above this temperature, diffuse magnetic scattering indicative of short-range magnetic order is observed, and this scattering persists up to TSRO = 650(10) K. Morevoer, the magnetic susceptibility shows a weak anomaly at TSRO and no anomaly at TN. Analysis of the diffuse scattering data using a reverse Monte Carlo algorithm indicates that abovemore » TN nearly two-dimensional, short-range magnetic order is present with a correlation length of 9.3(3) Å within the Mn layers at 400 K. The inelastic scattering data reveal a spin gap of 3.5 meV in the long-range ordered state, and strong, low-energy (quasielastic) magnetic excitations emerging in the short-range ordered state. When we compared it with other related compounds correlates the distortion of the Mn coordination tetrahedra to the sign of the magnetic exchange along the layer-stacking direction, and suggests that short-range order above TN is a common feature in the magnetic behavior of layered Mn-based pnictides and oxypnictides.« less

  1. On the structural defects in synthetic {gamma}-MnO{sub 2}s

    SciTech Connect (OSTI)

    Hill, L.I.; Verbaere, A. . E-mail: alain.verbaere@cnrs-imn.fr

    2004-12-01

    In the literature, the {gamma}-MnO{sub 2} structure is considered to be that of ramsdellite (R), in which two types of defects exist. The occurrence of a slab of pyrolusite (r) is named a De Wolff defect and random faults r in R give intergrowths of ramsdellite and pyrolusite, which account well for the global features of many experimental diffraction patterns. The other type of defect results from 'microtwinning', which allows the so-called {epsilon}-MnO{sub 2} to be put with {gamma}-MnO{sub 2} in the same classification. This paper discusses the previous models of defect and what could be the features of the 'microtwinning', giving for each possible model the corresponding expected features in reciprocal space. The results of a selected area electron diffraction study of rather well crystallized samples of {gamma}-MnO{sub 2} are presented. The splitting of particular diffraction spots and new diffuse intensity are interpreted as the first experimental evidence for 'microtwinning', and a model with orientation variants within microdomains embedded in a 'normal' structure is proposed, which is rather different from the previous hypotheses involving parallel twin planes and parallel twin boundaries.

  2. Ordering ferromagnetic In{sub 1?x}Mn{sub x}As quantum dots

    SciTech Connect (OSTI)

    Ferri, Fabio A.; Marega Jr, Euclydes; Kunets, Vasyl P.; Salamo, Gregory J.

    2013-12-04

    In this work, we present a method to order low temperature (LT) self-assembled ferromagnetic In{sub 1?x}Mn{sub x}As quantum dots (QDs) grown by molecular beam epitaxy (MBE). The ordered In{sub 1?x}Mn{sub x}As QDs were grown on top of a non-magnetic In{sub 0.4}Ga{sub 0.6}As/GaAs(100) QDs multi-layered structure. The modulation of the chemical potential, due to the stacking, provides a nucleation center for the LT In{sub 1?x}Mn{sub x}As QDs. For particular conditions, such as surface morphology and growth conditions, the In{sub 1?x}Mn{sub x}As QDs align along lines like chains. For comparison purposes, we also report the study of QDs grown on plain GaAs(100) substrates. Ferromagnetic behavior was observed for all structures at 2 K.

  3. CaMn2Sb2: Spin waves on a frustrated antiferromagnetic honeycomb lattice

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

    McNally, D. E.; Simonson, J. W.; Kistner-Morris, J. J.; Smith, G. J.; Hassinger, J. E.; DeBeer-Schmidt, L.; Kolesnikov, A. I.; Zaliznyak, I.; Aronson, M. C.

    2015-05-22

    We present inelastic neutron scattering measurements of the antiferromagnetic insulator CaMn2Sb2:, which consists of corrugated honeycomb layers of Mn. The dispersion of magnetic excitations has been measured along the H and L directions in reciprocal space, with a maximum excitation energy of ≈ 24 meV. These excitations are well described by spin waves in a Heisenberg model, including first and second neighbor exchange interactions, J1 and J2, in the Mn plane and also an exchange interaction between planes. The determined ratio J2/J1 ≈ 1/6 suggests that CaMn2Sb2: is the first example of a compound that lies very close to themore » mean field tricritical point, known for the classical Heisenberg model on the honeycomb lattice, where the N´eel phase and two different spiral phases coexist. The magnitude of the determined exchange interactions reveal a mean field ordering temperature ≈ 4 times larger than the reported N´eel temperature TN = 85 K, suggesting significant frustration arising from proximity to the tricritical point.« less

  4. Modulation on Ni{sub 2}MnGa(001) surface

    SciTech Connect (OSTI)

    D'Souza, S. W.; Rai, Abhishek; Nayak, J.; Maniraj, M.; Dhaka, R. S.; Barman, S. R.; Schlagel, D. L.; Lograsso, T. A.

    2011-07-15

    We report periodic modulation on (001) surface of Ni2MnGa ferromagnetic shape memory alloy. For the stoichiometric surface, analysis of the low energy electron diffraction (LEED) spot profiles shows that the modulation is incommensurate. The modulation appears at 200 K, concomitant with the first order structural transition to the martensitic phase.

  5. Aliovalent titanium substitution in layered mixed Li Ni-Mn-Co oxides for lithium battery applications

    SciTech Connect (OSTI)

    Kam, Kinson; Doeff, Marca M.

    2010-12-01

    Improved electrochemical characteristics are observed for Li[Ni1/3Co1/3-yMyMn1/3]O2 cathode materials when M=Ti and y<0.07, compared to the baseline material, with up to 15percent increased discharge capacity.

  6. --No Title--

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

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  7. Helical antiferromagnetic ordering in Lu1-xScxMnSi

    SciTech Connect (OSTI)

    Goetsch, Ryan J; Anand, V K; Johnston, David C

    2014-08-01

    Polycrystalline samples of Lu1?xScxMnSi (x=0, 0.25, 0.5) are studied using powder x-ray diffraction, heat capacity Cp, magnetization, magnetic susceptibility ?, and electrical resistivity ? measurements versus temperature T and magnetic field H. This system crystallizes in the primitive orthorhombic TiNiSi-type structure (space group Pnma) as previously reported. The ?(T) data indicate metallic behavior. The Cp(T), ?(T), and ?(T) measurements consistently indicate long-range antiferromagnetic (AF) transitions with AF ordering temperatures TN=246, 215, and 188 K for x=0, 0.25, and 0.5, respectively. A second transition is observed at somewhat lower T for each sample from the ?(T) and ?(T) measurements, which we speculate are due to spin reorientation transitions; these second transitions are completely suppressed in H=5.5 T. The Cp data below 10 K for each composition indicate an enhanced Sommerfeld electronic heat capacity coefficient for the series in the range ?=2429 mJ/mol K2. The ?(T) measurements up to 1000 K were fitted by local-moment Curie-Weiss behaviors which indicate a low Mn spin S?1. The ? data below TN are analyzed using the Weiss molecular field theory for a planar noncollinear cycloidal AF structure with a composition-dependent pitch, following the previous neutron diffraction work of Venturini et al. [J. Alloys Compd. 256, 65 (1997)]. Within this model, the fits indicate a turn angle between Mn ordered moments along the cycloid axis of ?100? or ?145?, either of which indicate dominant AF interactions between the Mn spins in the Lu1?xScxMnSi series of compounds.

  8. Structural relationships between new carbide La{sub 14}Sn(MnC{sub 6}){sub 3} and fully ordered La{sub 11}(MnC{sub 6}){sub 3}

    SciTech Connect (OSTI)

    Zaikina, Julia V.; Zhou, Haidong; Latturner, Susan E.

    2010-12-15

    Crystals of the ternary La{sub 11}(MnC{sub 6}){sub 3} and new quaternary carbide La{sub 14}Sn(MnC{sub 6}){sub 3} phases were grown from La/Ni eutectic flux and their structures were determined by means of X-ray single crystal diffraction. La{sub 11}(MnC{sub 6}){sub 3} is a new superstructure variant of La{sub 3.67}MnC{sub 6} (previously reported disordered subcell: P6{sub 3}/m; a{sub 0}=8.806 A; c{sub 0}=5.329 A, Z=2). The superstructure (R3-bar ; a={radical}3a{sub 0}=15.2649(9) A; c=3c{sub 0}=16.013(1) A, Z=6; R{sub 1}=0.022) is realized by complete ordering of the La chains within the columns of face-sharing carbon octahedra, with alternating La-La distances leading to R-centering and enlargement of the unit cell. The structure of the quaternary carbide La{sub 14}Sn(MnC{sub 6}){sub 3} (P6-bar ; a=8.756(1) A; c=10.483(2) A, Z=1; R{sub 1}=0.026) is closely related to that of La{sub 11}(MnC{sub 6}){sub 3} with part of the MnC{sub 6} units replaced by Sn atoms. The structure and precise composition of La{sub 14}Sn(MnC{sub 6}){sub 3} can be derived from that of La{sub 11}(MnC{sub 6}){sub 3} by taking into account the extent of this substitution and variation in lanthanum siting in the chain of carbon octahedra. Band structure calculations indicate both phases are metallic; the La{sub 11}(MnC{sub 6}){sub 3} phase is stabilized by the ordering of La atoms which induces a pseudogap at E{sub F}. -- La{sub 11}(MnC{sub 6}){sub 3} with fully ordered superstructure and a new carbide La{sub 14}Sn(MnC{sub 6}){sub 3} were obtained from La/Ni eutectic flux. Display Omitted

  9. The effects of annealing on the microstructure and mechanical properties of Fe28Ni18Mn33Al21

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

    Meng, Fanling; Qiu, Jingwen; Baker, Ian; Bei, Hongbin

    2015-08-20

    In this paper, As-cast Fe28Ni18Mn33Al21, which consists of aligned, 50 nm, (Ni, Al)-rich B2, and (Fe, Mn)-rich f.c.c. phases, was annealed at a variety of temperatures up to 1423 K and the microstructure and mechanical properties were examined. It was shown that the as-cast microstructure arises from a eutectoid transformation at ~1300 K. Annealing at temperatures ≤1073 K produces β-Mn-structured precipitates and hardness values up to 816 HV, while annealing at temperatures >1073 K leads to dramatic coarsening of the two-phase B2/f.c.c. microstructure (up to 5.5 µm after 50 h at 1273 K), but does not lead to β-Mn precipitation.more » Interestingly, annealing at temperatures >1073 K delays the onset of β-Mn precipitation during subsequent anneals at lower temperatures. Coarsening the B2/f.c.c. lamellar structure by annealing at higher temperatures softens it and leads to increases in ductility from fracture before yield to ~8 % elongation. Finally, the presence of β-Mn precipitates makes the very fine, brittle B2/f.c.c. microstructures even more brittle, but significant ductility (8.4 % elongation) is possible even with β-Mn precipitates present if the B2/f.c.c. matrix is coarse and, hence, more ductile.« less

  10. X-ray and Raman spectroscopic studies on Ru substituted LiMn{sub 2}O{sub 4}

    SciTech Connect (OSTI)

    Kalavathi, S.; Ravindran, T. R.; Sahu, P. Ch.; Kalaivani, D.

    2015-06-24

    Phase pure Ru substituted LiMn{sub 2}O{sub 4} charge frustrated spinel compounds have been synthesized. Ru substitution for Mn is possible only up to 7.5%. Powder diffraction measurements confirm sustenance of charge frustrated cubic phase with space group Fd3m upon substitution of Ru for Mn. An increase in lattice parameter has been observed indicating replacement of Mn as Ru{sup 3+} or Ru{sup 4+} rather than Ru{sup 5+}. Raman spectroscopic measurements show that the crystal structure is robust against an increase of laser power and the observed bands show an expected red shift. In the case of Ru substituted LiMn{sub 2}O{sub 4}, the A{sub 1g} symmetric stretching mode, the F{sup (1)}{sub 2g} and the F{sup (2)}{sub 2g} symmetric bending modes identified with the Mn-O octahedra show a red shift up to Ru 0.075 and at higher Ru concentrations, revert back to the frequency corresponding to the pristine LiMn{sub 2}O{sub 4}.

  11. Structural and magnetic properties of magnetron sputtered Ni-Mn-Sn ferromagnetic shape memory alloy thin films

    SciTech Connect (OSTI)

    Vishnoi, Ritu; Kaur, Davinder

    2010-05-15

    In the present study, structural and magnetic properties of Mn-rich, off-stoichiometric, nanocrystalline Ni-Mn-Sn ferromagnetic shape memory alloy thin films, grown on Si (100) substrates at 550 deg. C by dc magnetron sputtering have been systematically investigated. The crystallization, surface morphology, and structural features were studied using x-ray diffraction, atomic force microscopy, and field emission scanning electron microscopy. The structural transition from austenite to martensite was observed with an increase of Mn content. Austenitic phase with mixed L2{sub 1}/A2+B2 structure has been observed at room temperature in Ni{sub 52.6}Mn{sub 23.7}Sn{sub 23.6} (S{sub 1}) and Ni{sub 51.5}Mn{sub 26.1}Sn{sub 22.2} (S{sub 2}) films, while those with composition of Ni{sub 58.9}Mn{sub 28.0}Sn{sub 13.0} (S{sub 3}) and Ni{sub 58.3}Mn{sub 29.0}Sn{sub 12.6} (S{sub 4}) show martensitic phase with 14M modulated monoclinic structures. Field induced martensite-austenite transformation has been observed in magnetization studies using superconducting quantum interference device magnetometer. Temperature dependent magnetization measurements demonstrate the influence of magnetic field on the structural phase transition temperature. The investigations reveal an increase of martensitic transformation temperature (T{sub M}) with corresponding increase in substitution of Mn. The films exhibit ferromagnetic behavior at low temperatures below Curie temperature (T{sub C}). The decrease in saturation moment with increasing Mn content, indicates the existence of antiferromagnetic correlations within ferromagnetic matrix.

  12. First-principles study on the ferrimagnetic half-metallic Mn{sub 2}FeAs alloy

    SciTech Connect (OSTI)

    Qi, Santao; Zhang, Chuan-Hui; Chen, Bao; Shen, Jiang; Chen, Nanxian

    2015-05-15

    Mn-based full-Heusler alloys are kinds of promising candidates for new half-metallic materials. Basing on first principles, the electronic structures and magnetic properties of the Mn{sub 2}FeAs full-Heusler alloy have been investigated in detail. The Hg{sub 2}CuTi-type Mn{sub 2}FeAs compound obeys the Slater-Pauling rule, while the anti-parallel alignment atomic magnetic moments of Mn locating at different sites indicate it a ferrimagnetic alloy. The calculated spin-down bands behave half-metallic character, exhibiting a direct gap of 0.46 eV with a 100% spin polarization at the Fermi level. More studies show the compound would maintain half-metallic nature in a large range of variational lattice constants. We expect that our calculated results may trigger Mn{sub 2}FeAs applying in the future spintronics field. - Graphical abstract: The d orbitals of Mn and Fe atoms split into multi-degenerated levels which create new bonding and nonbonding states. These exchange splitting shift the Fermi level to origin band gap.▪ - Highlights: • The electronic structure and magnetic properties of Mn{sub 2}FeAs full-Heusler alloy were studied. • A total magnetic moment of 3μ{sub B} was obtained for Mn{sub 2}FeAs alloy, following the SP rule M{sub t}=Z{sub t}−24. • The origin of ferrimagnetism and half-metallic character in Mn{sub 2}FeAs were discussed.

  13. Facile and template-free preparation of {alpha}-MnO{sub 2} nanostructures and their enhanced adsorbability

    SciTech Connect (OSTI)

    Ma, Hongwei; Shen, Jianfeng; Shi, Min; Yan, Bo; Li, Na; Ye, Mingxin

    2011-09-15

    Graphical abstract: . The as-obtained ({alpha}-MnO{sub 2}) nanomaterials could act as an adsorbent to remove Conge red. More significantly, the nanomaterials are nontoxic and environmentally friendly though a biological MTT assay experiment. Plots of the capacity to remove Conge red with time by the commercial and new-prepared {alpha}-MnO{sub 2}. Inset shows absorption of Congo Red with time by new-prepared rod-clusters {alpha}-MnO{sub 2} (0, 10, 20, 40 and 60 min, respectively). Highlights: {yields} Nanostructured {alpha}-MnO{sub 2} was prepared through a template-free hydrothermal method. {yields} The obtained {alpha}-MnO{sub 2} could act as effective adsorbents to remove organic dyes. {yields} The obtained adsorbents are environmentally friendly. -- Abstract: In this paper, nanostructured MnO{sub 2} materials were successfully prepared through a simple and template-free hydrothermal method. X-ray diffraction pattern indicates that the as-prepared nanomaterials are {alpha}-MnO{sub 2}. Transmission Electron Microscopy and Scanning Electron Microscopy images demonstrate that nanostructured rod-clusters {alpha}-MnO{sub 2} could be evolved from the nanorods. Brunauer-Emmett-Teller (BET) surface area measurement was employed to characterize the surface property. Moreover, the as-obtained ({alpha}-MnO{sub 2}) nanomaterials could act as an efficient adsorbent to remove Congo Red and Methlylene Blue. More significantly, the nanomaterials are nontoxic and environmentally friendly via biological methylthiazolyldiphenyltetrazoliumbromide assay experiments. Its nontoxic and enhanced adsorbability properties guarantee their safe applications in environmental protection and industrial aspects.

  14. Atomic moments in Mn{sub 2}CoAl thin films analyzed by X-ray magnetic circular dichroism

    SciTech Connect (OSTI)

    Jamer, M. E.; Assaf, B. A.; Heiman, D.; Sterbinsky, G. E.; Arena, D. A.

    2014-12-07

    Spin gapless semiconductors are known to be strongly affected by structural disorder when grown epitaxially as thin films. The magnetic properties of Mn{sub 2}CoAl thin films grown on GaAs (001) substrates are investigated here as a function of annealing. This study investigates the atomic-specific magnetic moments of Mn and Co atoms measured through X-ray magnetic circular dichroism as a function of annealing and the consequent structural ordering. The results indicate that the structural distortion mainly affects the Mn atoms as seen by the reduction of the magnetic moment from its predicted value.

  15. Atomic moments in Mn2CoAl thin films analyzed by X-ray magnetic circular dichroism

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

    Jamer, M. E.; Assaf, B. A.; Sterbinsky, G. E.; Arena, D. A.; Heiman, D.

    2014-12-05

    Spin gapless semiconductors are known to be strongly affected by structural disorder when grown epitaxially as thin films. The magnetic properties of Mn2CoAl thin films grown on GaAs (001) substrates are investigated here as a function of annealing. This study investigates the atomic-specific magnetic moments of Mn and Co atoms measured through X-ray magnetic circular dichroism as a function of annealing and the consequent structural ordering. Results indicate that the structural distortion mainly affects the Mn atoms as seen by the reduction of the magnetic moment from its predicted value.

  16. Large enhancement of Blocking temperature by control of interfacial structures in Pt/NiFe/IrMn/MgO/Pt multilayers

    SciTech Connect (OSTI)

    Chen, Xi; Wang, Shouguo Han, Gang; Jiang, Shaolong; Yang, Kang; Liu, Qianqian; Yu, Guanghua; Liu, Jialong; Wang, Rongming

    2015-09-15

    The Blocking temperature (T{sub B}) of Pt/NiFe/IrMn/MgO/Pt multilayers was greatly enhanced from far below room temperature (RT) to above RT by inserting 1 nm thick Mg layer at IrMn/MgO interface. Furthermore, the exchange bias field (H{sub eb}) was increased as well by the control of interfacial structures. The evidence for a significant fraction of Mn-O bonding at IrMn/MgO interface without Mg insertion layer was provided by X-ray photoelectron spectroscopy. The bonding between Mn and O can decrease the antiferromagnetism of IrMn film, leading to lower value of T{sub B} in Pt/NiFe/IrMn/MgO/Pt multilayers. Ultrathin Mg film inserted at IrMn/MgO interface acting as an oxygen sinking layer can suppress the oxidation reactions between Mn and O and reduce the formation of Mn-O bonding greatly. The oxidation suppression results in the recovery of the antiferromagnetism of IrMn film, which can enhance T{sub B} and H{sub eb}. Furthermore, the high resolution transmission electron microscopy demonstrates that the Mg insertion layer can efficiently promote a high-quality MgO (200) texture. This study will enhance the understanding of physics in antiferromagnet-based spintronic devices.

  17. OPTICAL AND NEAR-INFRARED POLARIMETRY OF HIGHLY REDDENED Type Ia SUPERNOVA 2014J: PECULIAR PROPERTIES OF DUST IN M82

    SciTech Connect (OSTI)

    Kawabata, K. S.; Akitaya, H.; Itoh, R.; Moritani, Y. [Hiroshima Astrophysical Science Center, Hiroshima University, Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526 (Japan); Yamanaka, M. [Department of Physics, Faculty of Science and Engineering, Konan University, Okamoto, Kobe, Hyogo 658-8501 (Japan); Maeda, K.; Nogami, D. [Department of Astronomy, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502 (Japan); Ui, T.; Kawabata, M.; Mori, K.; Takaki, K.; Ueno, I.; Chiyonobu, S.; Harao, T.; Matsui, R.; Miyamoto, H.; Nagae, O. [Department of Physical Science, Hiroshima University, Kagamiyama, Higashi-Hiroshima 739-8526 (Japan); Nomoto, K.; Suzuki, N. [Kavli Institute for the Physics and Mathematics of the Universe (WPI), The University of Tokyo, Kashiwa, Chiba 277-8583 (Japan); Tanaka, M., E-mail: kawabtkj@hiroshima-u.ac.jp [National Astronomical Observatory of Japan, Osawa, Mitaka, Tokyo 181-8588 (Japan); and others

    2014-11-01

    We present optical and near-infrared multi-band linear polarimetry of the highly reddened Type Ia supernova (SN) 2014J that appeared in M82. SN 2014J exhibits large polarization at shorter wavelengths, e.g., 4.8% in the B band, which decreases rapidly at longer wavelengths, while the position angle of the polarization remains at approximately 40 over the observed wavelength range. These polarimetric properties suggest that the observed polarization is likely predominantly caused by the interstellar dust within M82. Further analysis shows that the polarization peaks at a wavelengths much shorter than those obtained for the Galactic dust. The wavelength dependence of the polarization can be better described by an inverse power law rather than by the Serkowski law for Galactic interstellar polarization. These points suggest that the nature of the dust in M82 may be different from that in our Galaxy, with polarizing dust grains having a mean radius of <0.1 ?m.

  18. Visible Light-Induced Electron Transfer from Di-mu-oxo Bridged Dinuclear Mn Complexes to Cr Centers in Silica Nanopores

    SciTech Connect (OSTI)

    Frei, Heinz; Weare, Walter W.; Pushkar, Yulia; Yachandra, Vittal K.; Frei, Heinz

    2008-06-03

    The compound (bpy)2MnIII(mu-O)2MnIV(bpy)2, a structural model relevant for the photosynthetic water oxidation complex, was coupled to single CrVI charge-transfer chromophores in the channels of the nanoporous oxide AlMCM-41. Mn K-edge EXAFS spectroscopy confirmed that the di-mu-oxo dinuclear Mn core of the complex is unaffected when loaded into the nanoscale pores. Observation of the 16-line EPR signal characteristic of MnIII(mu-O)2MnIV demonstrates that the majority of the loaded complexes retained their nascent oxidation state in the presence or absence of CrVI centers. The FT-Raman spectrum upon visible light excitation of the CrVI-OII --> CrV-OI ligand-to-metal charge-transfer reveals electron transfer from MnIII(mu-O)2MnIV (Mn-O stretch at 700 cm-1) to CrVI, resulting in the formation of CrV and MnIV(mu-O)2MnIV (Mn-O stretch at 645 cm-1). All initial and final states are directly observed by FT-Raman or EPR spectroscopy, and the assignments corroborated by X-ray absorption spectroscopy measurements. The endoergic charge separation products (DELTA Eo = -0.6 V) remain after several minutes, which points to spatial separation of CrV and MnIV(mu-O)2MnIV as a consequence of hole (OI) hopping as a major contributing mechanism. This is the first observation of visible light-induced oxidation of a potential water oxidation complex by a metal charge-transfer pump in a nanoporous environment. These findings will allow for the assembly and photochemical characterization of well defined transition metal molecular units, with the ultimate goal of performing endothermic, multi-electron transformations that are coupled to visible light electron pumps in nanostructured scaffolds.

  19. Penetration depth and absorption mechanisms of spin currents in Ir{sub 20}Mn{sub 80} and Fe{sub 50}Mn{sub 50} polycrystalline films by ferromagnetic resonance and spin pumping

    SciTech Connect (OSTI)

    Merodio, P.; Ghosh, A.; Lemonias, C.; Gautier, E.; Ebels, U.; Chshiev, M.; Béa, H. E-mail: helene.bea@cea.fr; Baltz, V. E-mail: helene.bea@cea.fr

    2014-01-20

    Spintronics relies on the spin dependent transport properties of ferromagnets (Fs). Although antiferromagnets (AFs) are used for their magnetic properties only, some fundamental F-spintronics phenomena like spin transfer torque, domain wall motion, and tunnel anisotropic magnetoresistance also occur with AFs, thus making AF-spintronics attractive. Here, room temperature critical depths and absorption mechanisms of spin currents in Ir{sub 20}Mn{sub 80} and Fe{sub 50}Mn{sub 50} are determined by F-resonance and spin pumping. In particular, we find room temperature critical depths originating from different absorption mechanisms: dephasing for Ir{sub 20}Mn{sub 80} and spin flipping for Fe{sub 50}Mn{sub 50}.

  20. IL1{beta}-mediated Stromal COX-2 signaling mediates proliferation and invasiveness of colonic epithelial cancer cells

    SciTech Connect (OSTI)

    Zhu, Yingting; Tissue Tech Inc, Miami, FL 33173 ; Zhu, Min; Lance, Peter

    2012-11-15

    COX-2 is a major inflammatory mediator implicated in colorectal inflammation and cancer. However, the exact origin and role of COX-2 on colorectal inflammation and carcinogenesis are still not well defined. Recently, we reported that COX-2 and iNOS signalings interact in colonic CCD18Co fibroblasts. In this article, we investigated whether activation of COX-2 signaling by IL1{beta} in primary colonic fibroblasts obtained from normal and cancer patients play a critical role in regulation of proliferation and invasiveness of human colonic epithelial cancer cells. Our results demonstrated that COX-2 level was significantly higher in cancer associated fibroblasts than that in normal fibroblasts with or without stimulation of IL-1{beta}, a powerful stimulator of COX-2. Using in vitro assays for estimating proliferative and invasive potential, we discovered that the proliferation and invasiveness of the epithelial cancer cells were much greater when the cells were co-cultured with cancer associated fibroblasts than with normal fibroblasts, with or without stimulation of IL1{beta}. Further analysis indicated that the major COX-2 product, prostaglandin E{sub 2}, directly enhanced proliferation and invasiveness of the epithelial cancer cells in the absence of fibroblasts. Moreover, a selective COX-2 inhibitor, NS-398, blocked the proliferative and invasive effect of both normal and cancer associate fibroblasts on the epithelial cancer cells, with or without stimulation of IL-1{beta}. Those results indicate that activation of COX-2 signaling in the fibroblasts plays a major role in promoting proliferation and invasiveness of the epithelial cancer cells. In this process, PKC is involved in the activation of COX-2 signaling induced by IL-1{beta} in the fibroblasts.

  1. Influence of Mn concentration on magnetic topological insulator MnxBi2−xTe3 thin-film Hall-effect sensor

    SciTech Connect (OSTI)

    Ni, Y.; Zhang, Z.; Nlebedim, I. C.; Hadimani, R. L.; Jiles, D. C.

    2015-06-11

    Hall-effect (HE) sensors based on high-quality Mn-doped Bi2Te3 topological insulator (TI) thin films have been systematically studied in this paper. Improvement of Hall sensitivity is found after doping the magnetic element Mn into Bi2Te3. The sensors with low Mn concentrations, MnxBi2-xTe3, x = 0.01 and 0.08 show the linear behavior of Hall resistance with sensitivity about 5 Ω/T. And their Hall sensitivity shows weak dependence on temperature. For sensors with high Mn concentration (x = 0.23), the Hall resistance with respect to magnetic field shows a hysteretic behavior. Moreover, its sensitivity shows almost eight times as high as that of the HE sensors with low Mn concentration. The highest sensitivity can reach 43 Ω/T at very low magnetic field. This increase of Hall sensitivity is caused by the occurrence of anomalous HE (AHE) after ferromagnetic phase transition. Our work indicates that the magnetic-element-doped TIs with AHE are good candidates for HE sensors.

  2. Spintronic properties of Li1.5Mn0.5Z (Z=As, Sb) compounds in...

    Office of Scientific and Technical Information (OSTI)

    Publisher's Accepted Manuscript: Spintronic properties of Li1.5Mn0.5Z (ZAs, Sb) compounds in the Cu2Sb structure This content will become publicly available on January 26, 2017 ...

  3. Post-Growth Annealing of Bridgman-grown CdZnTe and CdMnTe Crystals...

    Office of Scientific and Technical Information (OSTI)

    Nuclear Radiation Detectors Citation Details In-Document Search Title: Post-Growth Annealing of Bridgman-grown CdZnTe and CdMnTe Crystals for Room-temperature Nuclear ...

  4. Thermoelectric properties of nano-meso-micro β-MnO₂ powders as a function of electrical resistance

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

    Hedden, Morgan; Francis, Nick; Haraldsen, Jason T.; Ahmed, Towfiq; Constantin, Costel

    2015-07-15

    Particle sizes of manganese oxide (β-MnO₂) powders were modified by using a mortar and pestle ground method for period of times that varied between 15–60 min. Particle size versus ground time clearly shows the existence of a size-induced regime transition (i.e., regime I and II). Thermoelectric properties of β-MnO₂ powders as a function of electrical resistance in the range of RP = 10 - 80Ω were measured. Based on the data presented, we propose a model for the β-MnO₂ system in which nanometer-scale MnO₂ crystallites bond together through weak van der Waals forces to form larger conglomerates that span inmore » size from nanometer to micrometer scale.« less

  5. Electronic properties of Mn-phthalocyanine–C{sub 60} bulk heterojunctions: Combining photoemission and electron energy-loss spectroscopy

    SciTech Connect (OSTI)

    Roth, Friedrich; Lupulescu, Cosmin; Darlatt, Erik; Gottwald, Alexander; Eberhardt, Wolfgang

    2015-11-14

    The electronic properties of co-evaporated mixtures (blends) of manganese phthalocyanine and the fullerene C{sub 60} (MnPc:C{sub 60}) have been studied as a function of the concentration of the two constituents using two supplementary electron spectroscopic methods, photoemission spectroscopy (PES) and electron energy-loss spectroscopy (EELS) in transmission. Our PES measurements provide a detailed picture of the electronic structure measured with different excitation energies as well as different mixing ratios between MnPc and C{sub 60}. Besides a relative energy shift, the occupied electronic states of the two materials remain essentially unchanged. The observed energy level alignment is different compared to that of the related CuPc:C{sub 60} bulk heterojunction. Moreover, the results from our EELS investigations show that, despite the rather small interface interaction, the MnPc related electronic excitation spectrum changes significantly by admixing C{sub 60} to MnPc thin films.

  6. Anti-site disorder and improved functionality of Mn?NiX (X = Al, Ga, In, Sn) inverse Heusler alloys

    SciTech Connect (OSTI)

    Paul, Souvik; Kundu, Ashis; Ghosh, Subhradip; Sanyal, Biplab

    2014-10-07

    Recent first-principles calculations have predicted Mn?NiX (X = Al, Ga, In, Sn) alloys to be magnetic shape memory alloys. Moreover, experiments on Mn?NiGa and Mn?NiSn suggest that the alloys deviate from the perfect inverse Heusler arrangement and that there is chemical disorder at the sublattices with tetrahedral symmetry. In this work, we investigate the effects of such chemical disorder on phase stabilities and magnetic properties using first-principles electronic structure methods. We find that except Mn?NiAl, all other alloys show signatures of martensitic transformations in presence of anti-site disorder at the sublattices with tetrahedral symmetry. This improves the possibilities of realizing martensitic transformations at relatively low fields and the possibilities of obtaining significantly large inverse magneto-caloric effects, in comparison to perfect inverse Heusler arrangement of atoms. We analyze the origin of such improvements in functional properties by investigating electronic structures and magnetic exchange interactions.

  7. Laser activation of ferromagnetism in hydrogenated Ga{sub 1-x}Mn{sub x}As

    SciTech Connect (OSTI)

    Farshchi, R.; Dubon, O. D.; Hwang, D. J.; Misra, N.; Grigoropoulos, C. P.; Ashby, P. D.

    2008-01-07

    We demonstrate the local depassivation of hydrogenated Ga{sub 1-x}Mn{sub x}As by pulsed-laser annealing. The controlled removal of Mn-H defect complexes, which form upon hydrogenation and render Mn acceptors inactive, is achieved by focused laser irradiation. As a result, regions of electrically and ferromagnetically active Ga{sub 1-x}Mn{sub x}As are formed within a nonactive, otherwise structurally identical film. The hydrogenated films subjected to blanket laser depassivation display a Curie temperature T{sub C} up to 60 K, or 60% of the T{sub C} of the as-grown films. These results demonstrate the direct laser writing of mesoscopic ferromagnetically active regions as a viable route for the realization of planar, nanoscale spintronic systems.

  8. Expression of low-, intermediate-, and high-affinity IL-2 receptors on B cell lines derived from patients with undifferentiated lymphoma of Burkitt's and non-Burkitt's types

    SciTech Connect (OSTI)

    Benjamin, D.; Rosolen, A.; Wormsley, S.B.; DeBault, L.E.; Colamonici, O.R. )

    1990-08-01

    IL-2 receptors on T cells exist in at least three forms which differ in their ligand-binding affinity. The low-affinity IL-2 receptor (IL-2R) consists of the 55-kDa Tac protein (p55 alpha), the intermediate-affinity site corresponds to the 70-kDa molecule (p70 beta), and the high-affinity IL-2R consists of a noncovalent heterodimeric structure involving both p55 alpha and p70 beta. We studied 24 B cell lines (8 EBV-negative and 16 EBV-positive) for IL-2R expression in the presence or absence of the tumor promoter, teleocidin. 125I-IL-2 radioreceptor binding assays and crosslinking studies demonstrated the sole expression of p55 alpha in EBV-negative cell lines only, whereas p55 alpha present in EBV-positive cell lines was always associated with p70 beta to construct high-affinity IL-2R. p70 beta was not detected in any of the EBV-negative cell lines, but was expressed on most of the EBV-positive cell lines (13 of 16). Our data also indicate that the expression of p55 alpha and p70 beta by radiolabeling correlates with their expression in flow cytometry, and that a large excess of p55 alpha is required to construct high-affinity IL-2R. Coexpression of p55 alpha and p70 beta on human B cells contributed to constructing high-affinity IL-2R hybrid complex as shown by rapid association rate contributed by p55 alpha and slow dissociation rate by p70 beta; teleocidin's ability to induce p55 alpha on cell lines which express p70 beta only, resulting in appearance of high-affinity IL-2R; and blocking p55 alpha by anti-Tac mAb in cell lines which constitutively express high-affinity IL-2R eliminated both high- and low-affinity components. The existence of low, intermediate, and high IL-2R on human B cells bears important future implications for understanding the mechanism of IL-2 signaling and the role of IL-2 in B cell activation, proliferation, and differentiation.

  9. What is the valence of Mn in Ga1-xMnxN?

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

    Berlijn, Tom; Jarrell, Mark; Nelson, Ryky; Ku, Wei; Moreno, Juana

    2015-11-04

    Motivated by the potential high Curie temperature of Ga1-xMnxN, we investigate the controversial Mn valence in this diluted magnetic semiconductor. From a first-principles Wannier-function analysis of the high energy Hilbert space, we find unambiguously the Mn valence to be close to 2+(d5), but in a mixed spin configuration with average magnetic moments of 4µB. By integrating out high-energy degrees of freedom differently, we further demonstrate the feasibility of both effective d4 and d5 descriptions. These two descriptions offer simple pictures for local and extended properties of the system, and highlight the dual nature of its doped hole. Specifically, in themore » effective d5 description, we demonstrate novel physical effects absent in previous studies. Thus, our derivation highlights the richness of low-energy sectors in interacting many-body systems and the generic need for multiple effective descriptions.« less

  10. Magnetochromic effect in multiferroic R In 1 ₋ x Mn x O 3 ( R = Tb , Dy)

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

    Chen, P.; Holinsworth, B. S.; O'Neal, K. R.; Brinzari, T. V.; Mazumdar, D.; Topping, C. V.; Luo, X.; Cheong, S.-W.; Singleton, J.; McGill, S.; et al

    2015-05-26

    We combined high field magnetization and magneto-optical spectroscopy to investigate spin-charge coupling in Mn-substituted rare-earth indium oxides of chemical formula RIn₁₋xMnxO₃ (R=Tb, Dy). The edge states, on-site Mn³⁺d to d excitations, and rare-earth f-manifold excitations all track the magnetization energy due to dominant Zeeman interactions. The field-induced modifications to the rare-earth excitations are quite large because spin-orbit coupling naturally mixes spin and charge, suggesting that the next logical step in the design strategy should be to bring spin-orbit coupling onto the trigonal bipyramidal chromophore site with a 4 or 5d center.

  11. Magnetostructural phase transformations in Tb 1-x Mn 2

    SciTech Connect (OSTI)

    Zou, Junding; Paudyal, Durga; Liu, Jing; Mudryk, Yaroslav; Pecharsky, Vitalij K.; Gschneidner, Karl A.

    2015-01-16

    Magnetism and phase transformations in non-stoichiometric Tb1-xMn2 (x = 0.056, 0.039) have been studied as functions of temperature and magnetic field using magnetization, heat capacity, and X-ray powder diffraction measurements. Lowering the temperature, the compounds sequentially order ferrimagnetically and antiferromagnetically, and finally, exhibit spin reorientation transitions. Moreover, these structural distortions from room temperature cubic to low temperature rhombohedral structures occur at TN, and are accompanied by large volume changes reaching ~-1.27% and -1.42%, respectively. First principles electronic structure calculations confirm the phase transformation from the ferrimagnetic cubic structure to the antiferromagnetic rhombohedral structure in TbMn2.

  12. Extrinsic anomalous Hall effect in epitaxial Mn{sub 4}N films

    SciTech Connect (OSTI)

    Meng, M.; Wu, S. X. Ren, L. Z.; Zhou, W. Q.; Wang, Y. J.; Wang, G. L.; Li, S. W.

    2015-01-19

    Anomalous Hall effect (AHE) in ferrimagnetic Mn{sub 4}N epitaxial films grown by molecular-beam epitaxy is investigated. The longitudinal conductivity σ{sub xx} is within the superclean regime, indicating Mn{sub 4}N is a highly conducting material. We further demonstrate that the AHE signal in 40-nm-thick films is mainly due to the extrinsic contributions based on the analysis fitted by ρ{sub AH}=a′ρ{sub xx0}+bρ{sub xx}{sup 2} and σ{sub AH}∝σ{sub xx}. Our study not only provide a strategy for further theoretical work on antiperovskite manganese nitrides but also shed promising light on utilizing their extrinsic AHE to fabricate spintronic devices.

  13. Magneto-optical spectroscopy of ferromagnetic shape-memory Ni-Mn-Ga alloy

    SciTech Connect (OSTI)

    Veis, M. Beran, L.; Zahradnik, M.; Antos, R.; Straka, L.; Kopecek, J.; Fekete, L.; Heczko, O.

    2014-05-07

    Magneto-optical properties of single crystal of Ni{sub 50.1}Mn{sub 28.4}Ga{sub 21.5} magnetic shape memory alloy in martensite and austenite phase were systematically studied. Crystal orientation was approximately along (100) planes of parent cubic austenite. At room temperature, the sample was in modulated 10M martensite phase and transformed to cubic austenite at 323?K. Spectral dependence of polar magneto-optical Kerr effect was obtained by generalized magneto-optical ellipsometry with rotating analyzer in the photon energy range from 1.2 to 4?eV, and from room temperature to temperature above the Curie point. The Kerr rotation spectra exhibit prominent features typical for complexes containing Mn atoms. Significant spectral changes during transformation to austenite can be explained by different optical properties caused by changes in density of states near the Fermi energy.

  14. Low temperature magnetic properties of magnesium substituted YbMnO{sub 3}

    SciTech Connect (OSTI)

    Sattibabu, Bhumireddi Bhatnagar, Anil K. Mohan, Dasari Das, Dibakar Sundararaman, Mahadevan; Siruguri, Vasudeva; Rayaprol, Sudhindra

    2014-04-24

    Structural and magnetic properties of polycrystalline Yb{sub 1−x}Mg{sub x}MnO{sub 3} (x = 0, 0.05 and 0.10) hexagonal compounds prepared by solid state method, have been studied. The structural analyses of the samples were carried out by Rietveld analysis of neutron diffraction data. With increasing Mg content, we find that the lattice parameter a decreases and c increases whereas the overall Mn-O bond length decreases. Magnetization measured as a function of magnetic field at 2.5 K exhibits hysteresis, which is attributed to ferromagnetic like ordering of Yb{sup 3+} sublattice. Temperature dependence of ac magnetic susceptibility, χ{sub ac}(T), shows no signature of spin-glass behavior. χ”(T) exhibits a sudden increase at low temperatures which is due to ordering of Yb{sup 3+} sublattice.

  15. 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.

  16. Homogeneity testing and quantitative analysis of manganese (Mn) in vitrified Mn-doped glasses by laser-induced breakdown spectroscopy (LIBS)

    SciTech Connect (OSTI)

    Unnikrishnan, V. K.; Nayak, Rajesh; Kartha, V. B.; Santhosh, C. E-mail: unnikrishnan.vk@manipal.edu; Sonavane, M. S.; Yeotikar, R. G.; Shah, M. L.; Gupta, G. P.; Suri, B. M.

    2014-09-15

    Laser-induced breakdown spectroscopy (LIBS), an atomic emission spectroscopy method, has rapidly grown as one of the best elemental analysis techniques over the past two decades. Homogeneity testing and quantitative analysis of manganese (Mn) in manganese-doped glasses have been carried out using an optimized LIBS system employing a nanosecond ultraviolet Nd:YAG laser as the source of excitation. The glass samples have been prepared using conventional vitrification methods. The laser pulse irradiance on the surface of the glass samples placed in air at atmospheric pressure was about 1.710{sup 9} W/cm{sup 2}. The spatially integrated plasma emission was collected and imaged on to the spectrograph slit using an optical-fiber-based collection system. Homogeneity was checked by recording LIBS spectra from different sites on the sample surface and analyzing the elemental emission intensities for concentration determination. Validation of the observed LIBS results was done by comparison with scanning electron microscope- energy dispersive X-ray spectroscopy (SEM-EDX) surface elemental mapping. The analytical performance of the LIBS system has been evaluated through the correlation of the LIBS determined concentrations of Mn with its certified values. The results are found to be in very good agreement with the certified concentrations.

  17. Eu3+ as a dual probe for the determination of IL anion donor power: A combined luminescence spectroscopic and electrochemical approach

    SciTech Connect (OSTI)

    Babai, Arash; Kopiec, Gabriel; Lackmann, Anastasia; Mallick, Bert; Pitula, Slawomir; Tang, Sifu; Mudring, Anja-Verena

    2014-04-01

    This work is aimed at giving proof that Eu(Tf2N)(3) (Tf2N = bis(trifluoromethanesulfonyl)amide) can act as both an optical and electrochemical probe for the determination of the Lewis acidity of an ionic liquid anion. For that reason the luminescence spectra and cyclic voltammograms of dilute solutions of Eu(Tf2N)(3) in various ionic liquids were investigated. The Eu2+/3+ redox potential in the investigated ILs can be related to the Lewis basicity of the IL anion. The IL cation had little influence. The lower the determined halfwave potential, the higher the IL anion basicity. The obtained ranking can be confirmed by luminescence spectroscopy where a bathochromic shift of the D-5(0) -> F-7(4) transition indicates a stronger Lewis basicity of the IL anion. (C) 2014 Published by Elsevier B.V.

  18. MN Lup: X-RAYS FROM A WEAKLY ACCRETING T TAURI STAR

    SciTech Connect (OSTI)

    Guenther, H. M.; Wolk, S. J.; Wolter, U.; Robrade, J.

    2013-07-01

    Young T Tauri stars (TTS) are surrounded by an accretion disk, which over time disperses due to photoevaporation, accretion, and possibly planet formation. The accretion shock on the central star produces an UV/optical veiling continuum, line emission, and X-ray signatures. As the accretion rate decreases, the impact on the central star must change. In this article we study MN Lup, a young star where no indications of a disk are seen in IR observations. We present XMM-Newton and VLT/UVES observations, some of them taken simultaneously. The X-ray data show that MN Lup is an active star with L{sub X} /L{sub bol} close to the saturation limit. However, we find high densities (n{sub e} > 3 Multiplication-Sign 10{sup 10} cm{sup -3}) in the X-ray grating spectrum. This can be well fitted using an accretion shock model with an accretion rate of 2 Multiplication-Sign 10{sup -11} M{sub Sun} yr{sup -1}. Despite the simple H{alpha} line profile which has a broad component, but no absorption signatures as typically seen on accreting TTS, we find rotational modulation in Ca II K and in photospheric absorption lines. These line profile modulations do not clearly indicate the presence of a localized hot accretion spot on the star. In the H{alpha} line we see a prominence in absorption about 2R{sub *} above the stellar surface-the first of its kind on a TTS. MN Lup is also the only TTS where accretion is seen, but no dust disk is detected that could fuel it. We suggest that MN Lup presents a unique and short-lived state in the disk evolution. It may have lost its dust disk only recently and is now accreting the remaining gas at a very low rate.

  19. Magnetic fields and fluctuations in weakly Mn doped ZnGeP{sub 2}

    SciTech Connect (OSTI)

    Mengyan, P. W.; Lichti, R. L.; Baker, B. B.; Celebi, Y. G.; Catak, E.; Carroll, B. R.; Zawilski, K. T.; Schunemann, P. G.

    2014-02-21

    We report on our measurements of local and bulk magnetic features in weakly Mn doped ZnGeP{sub 2}. Utilizing muon spin rotation and relaxation measurements, we identify local ferromagnetic order and fluctuations in the local fields as sampled by an implanted muon (?{sup +}). We also report on field induced ferromagnetism occurring above the claimed paramagnetic to ferromagnetic transition temperature (T{sub c} = 312 K)

  20. Inverse Design of Mn-based ternary p-type wide-gap oxides

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

    used theory to predict band structure and transport properties for the d 5 transition metal (TM) oxides MnO and Fe 2 O 3 . Significance and Impact This work identified design principles for improving d 5 oxides as a new class of semiconductors with potential applications in energy conversion. Design Principles Demonstrated for Semiconducting d 5 Transition-Metal Oxides with Photovoltaic Applications Potential H. Peng and S. Lany, Phys. Rev. B (Rapid Comm.) 85, 201202(R) (2012). Figure 1:

  1. Thermoelectric study of crossroads material MnTe via sulfur doping

    SciTech Connect (OSTI)

    Xie, Wenjie Populoh, Sascha; Sagarna, Leyre; Trottmann, Matthias; Ga??zka, Krzysztof; Xiao, Xingxing; Liu, Yufei; He, Jian; Weidenkaff, Anke

    2014-03-14

    Here, we report thermoelectric study of crossroads material MnTe via iso-electronic doping S on the Te-site. MnTe{sub 1-x}S{sub x} samples with nominal S content of x?=?0.00, 0.05, and 0.10 were prepared using a melt-quench method followed by pulverization and spark plasma sintering. The X-ray powder diffraction, scanning electron microscopy, and ZAF-corrected compositional analysis confirmed that S uniformly substitutes Te up to slightly over 2%. A higher content of S in the starting materials led to the formation of secondary phases. The thermoelectric properties of MnTe{sub 1-x}S{sub x} samples were characterized by means of Seebeck coefficient, electrical conductivity, and thermal conductivity measurements from 300?K to 773?K. Furthermore, Hall coefficient measurements and a single parabolic band model were used to help gain insights on the effects of S-doping on the scattering mechanism and the carrier effective mass. As expected, S doping not only introduced hole charge carriers but also created short-range defects that effectively scatter heat-carrying phonons at elevated temperatures. On the other hand, we found that S doping degraded the effective mass. As a result, the ZT of MnTe{sub 0.9}S{sub 0.1} was substantially enhanced over the pristine sample near 400?K, while the improvement of ZT became marginal at elevated temperatures. A ZT???0.65 at 773?K was obtained in all three samples.

  2. paper-LSPP16

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

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    6 2010 Regional New Construction and Renovations Expenditures for Public K-12 Schools ($Million) Region New Schools Additions Renovation Total Region 1 (CT, MA, ME, NH, RI, VT) Region 2 (NJ, NY, PA) Region 3 (DE, MD, VA, WV) Region 4 (KY, NC, SC, TN) Region 5 (AL, FL, GA, MS) Region 6 (IN, MI, OH) Region 7 (IL, MN, WI) Region 8 (IA, KS, MO, NE) Region 9 (AR, LA, OK, TX) Region 10 (CO, MT, ND, NM, SD, UT, WY) Region 11 (AZ, CA, HI, NV) Region 12 (AK, ID, OR, WA) Total Source(s): School Planning

  6. Print

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

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    Office of Scientific and Technical Information (OSTI)

    Account Request *First Name: *Last Name: *Organization: *Phone: *Email: Fax: *Address: *City: *State: Select AL AK AZ AR CA CO CT DE DC FL GA HI ID IL IN IA KS KY LA ME MD MA MI MN MS MO MT NE NV NH NJ NM NY NC ND OH OK OR PA RI SC SD TN TX UT VT VA WA WV WI WY Zip Code: *Affiliation: Select Federal Contractor *Access Level: Select View Release Official Releasing Official: release *Site Input Code: Select A2EDAP - Atmosphere to Electrons (A2e) Data Archive and Portal, Pacific Northwest National

  8. Redox Active Layer-by-Layer Structures containing MnO2 Nanoparticles

    SciTech Connect (OSTI)

    Bazito, Fernanda; O'Brien, Robert; Buttry, Daniel A.

    2005-02-01

    Nanoscale materials provide unique properties that will enable new technologies and enhance older ones. One area of intense activity in which nanoscale materials are being used is in the development of new functional materials for battery applications. This effort promises superior materials with properties that circumvent many of the problems associated with traditional battery materials. Previously we have worked on several approaches for using nanoscale materials for application as cathode materials in rechargeable Li batteries. Our recent work has focused on synthesizing MnO2 nanoparticles and using these in layer-by-layer (LbL) structures to probe the redox properties of the nanoparticles. We show that the aqueous colloidal nanoparticles produced by butanol reduction of tetramethylammonium permanganate can be trapped in thin films using a layer-by-layer deposition approach, and that these films are both redox active and exhibit kinetically facile electrochemical responses. We show cyclic voltammetry of MnO2 colloidal nanoparticles entrapped in a LbL thin film at an ITO electrode surface using poly(diallyldimethylammonium chloride) (PDDA). CV experiments demonstrate that Li+ insertion accompanies Mn(IV) reduction in LiClO4 supporting electrolytes, and that reduction is hindered in supporting electrolytes containing only tetrabutylammonium cations. We also show that electron propagation through multilayer films is facile, suggesting that electrons percolate through the films via electron exchange between nanoparticles.

  9. Magnetization dynamics and frustration in the multiferroic double perovskite Lu2MnCoO6

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

    Zapf, Vivien S.; Ueland, B. G.; Laver, Mark; Lonsky, Martin; Pohlit, Merlin; Muller, Jens; Lancaster, Tom; Moller, Johannes S.; Blundell, Stephen J.; Singleton, John; et al

    2016-04-29

    Here, we investigate the magnetic ordering and the magnetization dynamics (from kHz to THz time scales) of the double perovskite Lu2MnCoO6 using elastic neutron diffraction, muon spin relaxation, and micro-Hall magnetization measurements. This compound is known to be a type II multiferroic with the interesting feature that a ferromagneticlike magnetization hysteresis loop couples to an equally hysteretic electric polarization in the bulk of the material despite a zero-field magnetic ordering of the type ↑↑↓↓ along Co-Mn spin chains. Here we explore the unusual dynamics of this compound and find extremely strong fluctuations, consistent with the axial next-nearest-neighbor Ising (ANNNI) modelmore » for frustrated spin chains. We identify three temperature scales in Lu2MnCoO6 corresponding to the onset of highly fluctuating long-range order below TN = 50±3 K identified from neutron scattering, the onset of magnetic and electric hysteresis, with change in kHz magnetic and electric dynamics below a 30 K temperature scale, and partial freezing of ~MHz spin fluctuations in the muon spin relaxation data below 12 ± 3 K. Our results provide a framework for understanding the multiferroic behavior of this compound and its hysteresis and dynamics.« less

  10. Magnetization-steps in Y?CoMnO? double perovskite: The role of antisite disorder

    SciTech Connect (OSTI)

    Nair, Harikrishnan S. Xiao, Yinguo; Brckel, Th.; Cherian, Dona; Elizabeth, Suja; Hansen, Thomas; Chatterji, Tapan

    2014-09-28

    Antisite disorder is observed to have significant impact on the magnetic properties of the double perovskite YCoMnO? which has been recently identified as a multiferroic. A paramagnetic-ferromagnetic phase transition occurs in this material at Tc ? 75 K. At 2 K, it displays a strong ferromagnetic hysteresis with a significant coercive field of Hc ? 15 kOe. Sharp steps are observed in the hysteresis curves recorded below 8 K. In the temperature range 2 K ? T ? 5 K, the hysteresis loops are anomalous as the virgin curve lies outside the main loop. The field-cooling conditions as well as the rate of field-sweep are found to influence the steps. Quantitative analysis of the neutron diffraction data shows that at room temperature, Y?CoMnO? consists of 62% of monoclinic P2?/n with nearly 70% antisite disorder and 38% Pnma. The bond valence sums indicate the presence of other valence states for Co and Mn which arise from disorder. We explain the origin of steps by using a model for pinning of magnetization at the antiphase boundaries created by antisite disorder. The steps in magnetization closely resemble the martensitic transformations found in intermetallics and display first-order characteristics as revealed in the Arrott's plots.

  11. MnO{sub 2}@colloid carbon spheres nanocomposites with tunable interior architecture for supercapacitors

    SciTech Connect (OSTI)

    Zhang, Yuxin; Liu, Chuanpu; Wen, Zhongquan

    2014-01-01

    Graphical abstract: - Highlights: MnO{sub 2}@CSs nanocomposites have been successfully synthesized in room temperature. The composites exhibited three structures: coreshell, yolkshell and hollow structure. The yolkshell structure exhibited a high specific capacitance and cycling stability. - Abstract: MnO{sub 2}@colloid carbon spheres nanocomposites with tunable interior architecture have been synthesized by a facile and cost-effective strategy at room temperature. The structure and morphology of as-prepared nanocomposites were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), nitrogen adsorption, focused ion beam scanning electron microscopy (FIB/SEM) and high-resolution transmission electron microscopy (HRTEM). The as-obtained composites exhibited a three-dimensional architecture with coreshell, yolkshell and hollow interior structure. Furthermore, the electrochemical properties of composites were evaluated by cycle voltammetric (CV) and galvanostatic chargedischarge measurements. The yolkshell structure exhibited the optimized pseudocapacitance performance, revealing a specific capacitance (273 F g{sup ?1}) with a good rate and cycling stability, owing to its unique structure and the poor crystallinity of MnO{sub 2} nanofilms. Therefore, this facile synthetic strategy could be useful to design and synthesis of tunable nanostructures with enhanced supercapacitor behavior.

  12. Magnetoelectric coupling tuned by competing anisotropies in Mn1−xNixTiO3

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

    Chi, Songxue; Ye, Feng; Zhou, H. D.; Choi, E. S.; Hwang, J.; Cao, Huibo; Fernandez-Baca, Jaime A.

    2014-10-24

    A flop of electric polarization from Pmore » $$\\|$$c (Pc) to P$$\\|$$ a (Pa) is observed in MnTiO3 as a spin flop transtion is triggered by a c-axis magnetic field, H$$\\|$$c=7 T. The critical magnetic field for Pa is significantly reduced in Mn1-xNixTiO3 (x=0.33). Neutron diffraction measurements revealed similar magnetic arrangements for the two compositions where the ordered spins couple antiferromagnetically with their nearest intra- and inter-planar neighbors. In the x=0.33 system, the single ion anisotropies of Mn2+ and Ni2+ compete and give rise to an additional spin reorientation transition at TR. A magnetic field, Hc, aligns the spins along c for TRN. The rotation of the collinear spins away from the c-axis for TR alters the magnetic point symmetry and gives rise to new ME susceptibility tensor form. Such linear ME response provides satisfactory explanation for behavior of field-induced electric polarization in both compositions. As the Ni content increases to x=0.5 and 0.68, the ME effect disappears as a new magnetic phase emerges.« less

  13. Spin-phonon study of EuMn{sub 2}O{sub 5} nanorods

    SciTech Connect (OSTI)

    Hsu, Ting-Wei; Yang, Chung-Cheun Tong, Yong-Xiang; Shih, Wei-Jhe; Lin, Kuen-Song

    2015-05-07

    EuMn{sub 2}O{sub 5} multiferroic nanorods, with diameters radial × (〈L{sub C}〉) lengths of 25(6) nm × 47(15) nm and 51(16) nm × 70(26) nm, were fabricated by the hydrothermal method. Ferrimagnetic ordering below 50 K (T*) is observed in the 〈L{sub C}〉 = 70 nm sample, which exhibited ferromagnetic (FM) behavior below T* in a field cooling process. No similar behavior was found in the 〈L{sub C}〉 = 47 nm sample. These observations reveal that only the 〈L{sub C}〉 = 70 nm sample has a meta-FM state, and this sample exhibits the stronger coupling between the Mn ions. Raman spectra of both sets of samples were obtained in 0, 610, 1000, 1600, and 2000 G magnetic fields. The red-shift of the A{sub g} (681 cm{sup −1}) mode of the both samples increased with the strength of the field above 1000 G, indicating the existence of spin-phonon interaction. The smaller sampled exhibited a larger red-shift, suggesting that the size importantly affects the of EuMn{sub 2}O{sub 5} nanorods.

  14. Antiferromagnetic dipolar ordering in [Co{sub 2}MnGe/V]{sub N} multilayers

    SciTech Connect (OSTI)

    Bergmann, A.; Grabis, J.; Zabel, H.; Westerholt, K.; Toperverg, B.P.; Leiner, V.; Wolff, M.

    2005-12-01

    We have studied [Co{sub 2}MnGe/V]{sub N} multilayers with a thickness of the V layers t{sub V} between 1.5 and 10 nm and a fixed thickness of the Heusler layer t{sub Co{sub 2}}{sub MnGe}=3 nm by x-ray scattering, neutron reflectivity, and magnetization measurements. In the thickness range t{sub V}{<=}3 nm neutron reflectivity results provide clear evidence for an antiferromagnetic (af) interlayer long-range order below a Neel temperature T{sub N}. The interlayer long range order does not show an oscillating character and is stabilized by a weak af coupling field H{sub af}{approx_equal}100 Oe. We attribute the af coupling to magnetic dipolar stray fields originating from magnetically rough surfaces of a granular Co{sub 2}MnGe microstructure. In the thickness range t{sub V}{>=}4 nm the multilayers undergo a cluster glass transition at T{sub f}{approx_equal}150 K. At high temperatures above T{sub N} or T{sub f} the mutilayers are superparamagnetic with a huge cluster magnetic moment {mu}{sub c}{>=}10{sup 5}{mu}{sub B}.

  15. Mesoporous MnCeOx solid solutions for low temperature and selective oxidation of hydrocarbons

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

    Zhang, Pengfei; Lu, Hanfeng; Zhou, Ying; Zhang, Li; Wu, Zili; Yang, Shize; Shi, Hongliang; Zhu, Qiulian; Chen, Yinfei; Dai, Sheng

    2015-10-15

    The development of noble-metal-free heterogeneous catalysts that can realize the aerobic oxidation of C–H bonds at low temperature is a profound challenge in the catalysis community. Here we report the synthesis of a mesoporous Mn0.5Ce0.5Ox solid solution that is highly active for the selective oxidation of hydrocarbons under mild conditions (100–120 °C). Notably, the catalytic performance achieved in the oxidation of cyclohexane to cyclohexanone/cyclohexanol (100 °C, conversion: 17.7%) is superior to those by the state-of-art commercial catalysts (140–160 °C, conversion: 3-5%). Finally, the high activity can be attributed to the formation of a Mn0.5Ce0.5Ox solid solution with an ultrahigh manganesemore » doping concentration in the CeO2 cubic fluorite lattice, leading to maximum active surface oxygens for the activation of C–H bonds and highly reducible Mn4+ ions for the rapid migration of oxygen vacancies from the bulk to the surface.« less

  16. Kinetics of MN based sorbents for hot coal gas. Quarterly report, September--December 1996

    SciTech Connect (OSTI)

    1996-12-31

    Manganese-based sorbents have been investigated for the removal of hydrogen sulfide (the primary sulfur bearing compound) from hot coal gases prior to its use in combined cycle turbines. Four formulations of Mn-based sorbents were tested in an ambient-pressure fixed-bed reactor to determine steady state H{sub 2}S concentrations, breakthrough times and effectiveness of the sorbent when subjected to cyclic sulfidation and regeneration testing. In a previous report, the sulfidation results were presented. Manganese-based sorbents with molar ratios > 1:1 Mn:Substrate were effective in reducing the H{sub 2}S concentration in simulated coal gases to less than 100 ppmv over five cycles. Actual breakthrough time for formulation C6-2-1100 was as high as 73% of breakthrough time based on wt% Mn in sorbent. In this report, the regeneration results will be presented. Regeneration tests determined that loaded pellets can be fully regenerated in air/steam mixture at 750{degrees}C with minimal sulfate formation. 16 refs., 9 figs., 5 tabs.

  17. Incommensurate crystal supercell and polarization flop observed in the magnetoelectric ilmenite MnTiO3

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

    Silverstein, Harlyn J.; Skoropata, Elizabeth; Sarte, Paul M.; Mauws, Cole; Aczel, Adam A.; Choi, Eun Sang; van Lierop, Johan; Wiebe, Christopher R.; Zhou, Haidong

    2016-02-19

    In the last few years the magnetoelectric behavior of MnTiO3 has been observed even though its been studied for many decades. We use neutron scattering on two separately grown single crystals and two powder samples to show the presence of a supercell that breaks R (3) over bar symmetry. We also present the temperature and field dependence of the dielectric constant and pyroelectric current and show evidence of nonzero off-diagonal magnetoelectric tensor elements (forbidden by R (3) over bar symmetry) followed by a polarization flop accompanying the spin flop transition at mu H-0(SF) = 6.5T. Mossbauer spectroscopy on MnTiO3 gentlymore » doped with Fe-57 was used to help shed light on the impact of the supercell on the observed behavior. Moreover, the full supercell structure could not be solved at this time due to a lack of visible reflections, the full scope of the results presented here suggest that the role of local spin-lattice coupling in the magnetoelectric properties of MnTiO3 is likely more important than previously thought.« less

  18. Correlating Local Structure with Electrochemical Activity in Li2MnO3

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

    Nanda, Jagjit; Sacci, Robert L.; Veith, Gabriel M.; Dixit, Hemant M.; Cooper, Valentino R.; Pezeshki, Alan M.; Ruther, Rose E.

    2015-07-31

    Li2MnO3 is of interest as one component of the composite lithium-rich oxides, which are under development for high capacity, high voltage cathodes in lithium ion batteries. Despite such practical importance, the mechanism of electrochemical activity in Li2MnO3 is contested in the literature, as are the effects of long-term electrochemical cycling. Here, Raman spectroscopy and mapping are used to follow the chemical and structural changes that occur in Li2MnO3. Both conventional slurry electrodes and thin films are studied as a function of the state of charge (voltage) and cycle number. Thin films have similar electrochemical properties as electrodes prepared from slurries,more » but allow for spectroscopic investigations on uniform samples without carbon additives. Spectral changes correlate well with electrochemical activity and support a mechanism whereby capacity is lost upon extended cycling due to the formation of new manganese oxide phases. Raman mapping of both thin film and slurry electrodes charged to different voltages reveals significant variation in the local structure. Poor conductivity and slow kinetics associated with a two-phase reaction mechanism contribute to the heterogeneity.« less

  19. Preparation and characterization of nanostructured NiO/MnO{sub 2} composite electrode for electrochemical supercapacitors

    SciTech Connect (OSTI)

    Liu Enhui Li Wen; Li Jian; Meng Xiangyun; Ding Rui; Tan Songting

    2009-05-06

    Nanostructured nickel-manganese oxides composite was prepared by the sol-gel and the chemistry deposition combination new route. The surface morphology and structure of the composite were characterized by scanning electron microscope and X-ray diffraction. The as-synthesized NiO/MnO{sub 2} samples exhibit higher surface area of 130-190 m{sup 2} g{sup -1}. Cyclic voltammetry and galvanostatic charge/discharge measurements were applied to investigate the electrochemical performance of the composite electrodes with different ratios of NiO/MnO{sub 2}. When the mass ratio of MnO{sub 2} and NiO in composite material is 80:20, the specific capacitance value of NiO/MnO{sub 2} calculated from the cyclic voltammetry curves is 453 F g{sup -1}, for pure NiO and MnO{sub 2} are 209, 330 F g{sup -1} in 6 mol L{sup -1} KOH electrolyte and at scan rate of 10 mV s{sup -1}, respectively. The specific capacitance of NiO/MnO{sub 2} electrode is much larger than that of each pristine component. Moreover, the composite electrodes showed high power density and stable electrochemical properties.

  20. The structure of the Caenorhabditis elegans manganese superoxide dismutase MnSOD-3-azide complex

    SciTech Connect (OSTI)

    Hunter, Gary J.; Trinh, Chi H.; Bonetta, Rosalin; Stewart, Emma E.; Cabelli, Diane E.; Hunter, Therese

    2015-08-27

    C. elegans MnSOD-3 has been implicated in the longevity pathway and its mechanism of catalysis is relevant to the aging process and carcinogenesis. The structures of MnSOD-3 provide unique crystallographic evidence of a dynamic region of the tetrameric interface (residues 41–54). We have determined the structure of the MnSOD-3-azide complex to 1.77-Å resolution. The analysis of this complex shows that the substrate analog, azide, binds end-on to the manganese center as a sixth ligand and that it ligates directly to a third and new solvent molecule also positioned within interacting distance to the His30 and Tyr34 residues of the substrate access funnel. This is the first structure of a eukaryotic MnSOD-azide complex that demonstrates the extended, uninterrupted hydrogen-bonded network that forms a proton relay incorporating three outer sphere solvent molecules, the substrate analog, the gateway residues, Gln142, and the solvent ligand. This configuration supports the formation and release of the hydrogen peroxide product in agreement with the 5-6-5 catalytic mechanism for MnSOD. The high product dissociation constant k₄ of MnSOD-3 reflects low product inhibition making this enzyme efficient even at high levels of superoxide.

  1. A XANES and EXAFS Study of Hydration and Ion Pairing in Ambient Aqueous MnBr[subscript 2] Solutions

    SciTech Connect (OSTI)

    Chen, Yongsheng; Fulton, John L.; Partenheimer, Walter

    2008-09-25

    Extended X-ray absorption fine structure (EXAFS) and X-ray absorption near edge structure (XANES) spectroscopies were used to probe the first-shell coordination structure of Mn(II) in aqueous MnBr{sub 2} solutions at ambient conditions from very dilute to the near saturation limit. The Mn K-edge EXAFS spectra for 0.05 and 0.2 m solutions showed that there was no Br(-I) in the first shell, and that the Mn(II) was fully hydrated with six water molecules in an octahedral arrangement. In contrast, for 6 m solution, the coordination number of water was reduced to about 5, and an average of about one bromine atom was present in the first shell as a contact ion pair. The 1s {yields} 4p transition at 6545.5 eV confirmed the observation of Mn-Br contact ion pairs at high concentrations and the 1s {yields} 3d transition at 6539.5 eV showed that the first shell coordination symmetry remained octahedral even in the presence of Mn-Br ion pairs.

  2. Role of the antiferromagnetic pinning layer on spin wave properties in IrMn/NiFe based spin-valves

    SciTech Connect (OSTI)

    Gubbiotti, G. Tacchi, S.; Del Bianco, L.; Bonfiglioli, E.; Giovannini, L.; Spizzo, F.; Zivieri, R.; Tamisari, M.

    2015-05-07

    Brillouin light scattering (BLS) was exploited to study the spin wave properties of spin-valve (SV) type samples basically consisting of two 5 nm-thick NiFe layers (separated by a Cu spacer of 5 nm), differently biased through the interface exchange coupling with an antiferromagnetic IrMn layer. Three samples were investigated: a reference SV sample, without IrMn (reference); one sample with an IrMn underlayer (10 nm thick) coupled to the bottom NiFe film; one sample with IrMn underlayer and overlayer of different thickness (10 nm and 6 nm), coupled to the bottom and top NiFe film, respectively. The exchange coupling with the IrMn, causing the insurgence of the exchange bias effect, allowed the relative orientation of the NiFe magnetization vectors to be controlled by an external magnetic field, as assessed through hysteresis loop measurements by magneto-optic magnetometry. Thus, BLS spectra were acquired by sweeping the magnetic field so as to encompass both the parallel and antiparallel alignment of the NiFe layers. The BLS results, well reproduced by the presented theoretical model, clearly revealed the combined effects on the spin dynamic properties of the dipolar interaction between the two NiFe films and of the interface IrMn/NiFe exchange coupling.

  3. Structure of the c(2x2) Mn/Ni(001) surface alloy by quantitative photoelectron diffraction

    SciTech Connect (OSTI)

    Banerjee, S.; Denlinger, J.; Chen, X.

    1997-04-01

    Surface alloys are two-dimensional metallic systems that can have structures that are unique to the surface, and have no counterpart in the bulk binary phase diagram. A very unusual structure was reported for the Mn-Ni system, based on a quantitative LEED structure determination, which showed that the Mn atoms were displaced out of the surface by a substantial amount. This displacement was attributed to a large magnetic moment on the Mn atoms. The structure of the Mn-Ni surface alloy was proposed to be based on a bulk termination model. Magnetic measurements on the Mn-Ni surface alloys, however, showed conclusively that the magnetic structure of these surface alloys is completely different from the bulk alloy analogs. For example, bulk MnNi is an antiferromagnet, whereas the surface alloy is ferromagnetic. This suggests that the proposed structure based on bulk termination, may not be correct. X-ray Photoelectron Diffraction (XPD) techniques were used to investigate this structure, using both a comparison to multiple scattering calculations and photoelectron holography. In this article the authors present some of the results from the quantitative analysis of individual diffraction patterns by comparison to theory.

  4. C E N T R A L F IL E S

    Office of Legacy Management (LM)

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  5. Why MnIn{sub 2}O{sub 4} spinel is not a transparent conducting oxide?

    SciTech Connect (OSTI)

    Martinez-Lope, M.J.; Retuerto, M.; Calle, C. de la; Porcher, Florence

    2012-03-15

    The title compound has been synthesized by a citrate technique. The crystal structure has been investigated at room temperature from high-resolution neutron powder diffraction (NPD) data. It crystallizes in a cubic spinel structure, space group Fd3-bar m, Z=8, with a=9.0008(1) A at 295 K. It exhibits a crystallographic formula (Mn{sub 0.924(2)}In{sub 0.076(2)}){sub 8a}(In{sub 1.804(2)}Mn{sub 0.196(2)}){sub 16d}O{sub 4}, where 8a and 16d stand for the tetrahedral and octahedral sites of the spinel structure, respectively, with a slight degree of inversion, {lambda}=0.08. MnIn{sub 2}O{sub 4} shows antiferromagnetic interactions below T{sub N} Almost-Equal-To 40 K, due to the statistical distribution of Mn ions over the two available sites. Unlike the related MgIn{sub 2}O{sub 4} and CdIn{sub 2}O{sub 4} spinels, well known as transparent conducting oxides, MnIn{sub 2}O{sub 4} is not transparent and shows a poor conductivity ({sigma}=0.38 S cm{sup -1} at 1123 K): the presence of Mn ions, able to adopt mixed valence states, localizes the charges that, otherwise, would be delocalized in the spinel conduction band. - Graphical Abstract: From NPD data the crystallographic formula (Mn{sub 0.924(2)}In{sub 0.076(2)}){sub 8a}(In{sub 1.804(2)}Mn{sub 0.196(2)}){sub 16d}O{sub 4}, shows a slight degree of inversion, {lambda}=0.08 and a certain In deficiency. The presence of Mn ions, able to adopt mixed oxidation states, localize the charges that, otherwise, would be delocalized in the spinel conduction band; the presence of localized Mn{sup 2+} and Mn{sup 3+} ions provides the characteristic brown color. Highlights: Black-Right-Pointing-Pointer Accurate structural determination from NPD data: inversion degree (8%), and In deficiency. Black-Right-Pointing-Pointer Bond-valence indicates Mn{sup 2+}-Mn{sup 3+} ions; edge-sharing octahedra contain 90% In{sup 3+}+10% Mn{sup 3+} cations. Black-Right-Pointing-Pointer Conductivity several orders of magnitude lower than those of MgIn{sub 2}O

  6. Structure of the unique SEFIR domain from human interleukin 17 receptor A reveals a composite ligand-binding site containing a conserved α-helix for Act1 binding and IL-17 signaling

    SciTech Connect (OSTI)

    Zhang, Bing; Liu, Caini; Qian, Wen; Han, Yue; Li, Xiaoxia; Deng, Junpeng

    2014-05-01

    Crystal structure of the SEFIR domain from human IL-17 receptor A provides new insights into IL-17 signaling. Interleukin 17 (IL-17) cytokines play a crucial role in mediating inflammatory and autoimmune diseases. A unique intracellular signaling domain termed SEFIR is found within all IL-17 receptors (IL-17Rs) as well as the key adaptor protein Act1. SEFIR-mediated protein–protein interaction is a crucial step in IL-17 cytokine signaling. Here, the 2.3 Å resolution crystal structure of the SEFIR domain of IL-17RA, the most commonly shared receptor for IL-17 cytokine signaling, is reported. The structure includes the complete SEFIR domain and an additional α-helical C-terminal extension, which pack tightly together to form a compact unit. Structural comparison between the SEFIR domains of IL-17RA and IL-17RB reveals substantial differences in protein topology and folding. The uniquely long insertion between strand βC and helix αC in IL-17RA SEFIR is mostly well ordered, displaying a helix (αCC′{sub ins}) and a flexible loop (CC′). The DD′ loop in the IL-17RA SEFIR structure is much shorter; it rotates nearly 90° with respect to the counterpart in the IL-17RB SEFIR structure and shifts about 12 Å to accommodate the αCC′{sub ins} helix without forming any knots. Helix αC was identified as critical for its interaction with Act1 and IL-17-stimulated gene expression. The data suggest that the heterotypic SEFIR–SEFIR association via helix αC is a conserved and signature mechanism specific for IL-17 signaling. The structure also suggests that the downstream motif of IL-17RA SEFIR together with helix αC could provide a composite ligand-binding surface for recruiting Act1 during IL-17 signaling.

  7. TYPE Ia SUPERNOVA REMNANT SHELL AT z = 3.5 SEEN IN THE THREE SIGHTLINES TOWARD THE GRAVITATIONALLY LENSED QSO B1422+231

    SciTech Connect (OSTI)

    Hamano, Satoshi; Kobayashi, Naoto [Institute of Astronomy, University of Tokyo, 2-21-1 Osawa, Mitaka, Tokyo 181-0015 (Japan); Kondo, Sohei [Koyama Astronomical Observatory, Kyoto-Sangyo University, Motoyama, Kamigamo, Kita-Ku, Kyoto 603-8555 (Japan); Tsujimoto, Takuji [National Astronomical Observatory of Japan and Department of Astronomical Science, Graduate University for Advanced Studies, 2-21-1 Osawa, Mitaka, Tokyo 181-0015 (Japan); Okoshi, Katsuya [Faculty of Industrial Science and Technology, Tokyo University of Science, 102-1 Tomino, Oshamanbe, Hokkaido 049-3514 (Japan); Shigeyama, Toshikazu, E-mail: hamano@ioa.s.u-tokyo.ac.jp [Research Center for the Early Universe, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033 (Japan)

    2012-08-01

    Using the Subaru 8.2 m Telescope with the IRCS Echelle spectrograph, we obtained high-resolution (R = 10,000) near-infrared (1.01-1.38 {mu}m) spectra of images A and B of the gravitationally lensed QSO B1422+231 (z = 3.628) consisting of four known lensed images. We detected Mg II absorption lines at z = 3.54, which show a large variance of column densities ({approx}0.3 dex) and velocities ({approx}10 km s{sup -1}) between sightlines A and B with a projected separation of only 8.4h{sup -1}{sub 70} pc at that redshift. This is the smallest spatial structure of the high-z gas clouds ever detected after Rauch et al. found a 20 pc scale structure for the same z = 3.54 absorption system using optical spectra of images A and C. The observed systematic variances imply that the system is an expanding shell as originally suggested by Rauch et al. By combining the data for three sightlines, we managed to constrain the radius and expansion velocity of the shell ({approx}50-100 pc, 130 km s{sup -1}), concluding that the shell is truly a supernova remnant (SNR) rather than other types of shell objects, such as a giant H II region. We also detected strong Fe II absorption lines for this system, but with much broader Doppler width than that of {alpha}-element lines. We suggest that this Fe II absorption line originates in a localized Fe II-rich gas cloud that is not completely mixed with plowed ambient interstellar gas clouds showing other {alpha}-element low-ion absorption lines. Along with the Fe richness, we conclude that the SNR is produced by an SN Ia explosion.

  8. Single high-dose irradiation aggravates eosinophil-mediated fibrosis through IL-33 secreted from impaired vessels in the skin compared to fractionated irradiation

    SciTech Connect (OSTI)

    Lee, Eun-Jung; Kim, Jun Won; Yoo, Hyun; Kwak, Woori; Choi, Won Hoon; Cho, Seoae; Choi, Yu Jeong; Lee, Yoon-Jin; Cho, Jaeho

    2015-08-14

    We have revealed in a porcine skin injury model that eosinophil recruitment was dose-dependently enhanced by a single high-dose irradiation. In this study, we investigated the underlying mechanism of eosinophil-associated skin fibrosis and the effect of high-dose-per-fraction radiation. The dorsal skin of a mini-pig was divided into two sections containing 4-cm{sup 2} fields that were irradiated with 30 Gy in a single fraction or 5 fractions and biopsied regularly over 14 weeks. Eosinophil-related Th2 cytokines such as interleukin (IL)-4, IL-5, and C–C motif chemokine-11 (CCL11/eotaxin) were evaluated by quantitative real-time PCR. RNA-sequencing using 30 Gy-irradiated mouse skin and functional assays in a co-culture system of THP-1 and irradiated-human umbilical vein endothelial cells (HUVECs) were performed to investigate the mechanism of eosinophil-mediated radiation fibrosis. Single high-dose-per-fraction irradiation caused pronounced eosinophil accumulation, increased profibrotic factors collagen and transforming growth factor-β, enhanced production of eosinophil-related cytokines including IL-4, IL-5, CCL11, IL-13, and IL-33, and reduced vessels compared with 5-fraction irradiation. IL-33 notably increased in pig and mouse skin vessels after single high-dose irradiation of 30 Gy, as well as in irradiated HUVECs following 12 Gy. Blocking IL-33 suppressed the migration ability of THP-1 cells and cytokine secretion in a co-culture system of THP-1 cells and irradiated HUVECs. Hence, high-dose-per-fraction irradiation appears to enhance eosinophil-mediated fibrotic responses, and IL-33 may be a key molecule operating in eosinophil-mediated fibrosis in high-dose-per fraction irradiated skin. - Highlights: • Single high-dose irradiation aggravates eosinophil-mediated fibrosis through IL-33. • Vascular endothelial cells damaged by high-dose radiation secrete IL-33. • Blocking IL-33 suppressed migration of inflammatory cells and cytokine secretion. • IL

  9. m/sup +/SR studies on pure MnF/sub 2/ and site-diluted (Mn/sub 0. 5/Zn/sub 0. 5/)F/sub 2/

    SciTech Connect (OSTI)

    Uemura, Y.J.; Keitel, R.; Senba, M.; Kiefl, R.F.; Kreitzman, S.R.; Noakes, D.R.; Brewer, J.H.; Harshman, D.R.; Ansaldo, E.J.; Crowe, K.M.

    1986-01-01

    Positive muon spin rotation and relaxation measurements have been carried out on the antiferromagnets, pure MnF/sub 2/ and site-diluted (Mn/sub 0.5/Zn/sub 0.5/)F/sub 2/, above and below the Neel temperature T/sub N/ using single-crystal specimens. Two different muon signals have been found in the pure MnF/sub 2/; with the precession frequency nu/sub A/ = 1.3 GHz for the site A and nu/sub B/ = 152 MHz for the site B measured in zero external magnetic field at T = 5 K. We propose a picture that the signal from the A site represents the ''muonium'' state, and discuss the characteristic features of muonium in magnetic materials. The spin relaxation rate 1/T/sub 1/, measured in zero external field, decreases rapidly with decreasing temperature below T/sub N/. The mechanism of the spin relaxation above T/sub N/ is explained by the exchange fluctuations of the Mn moments, while below T/sub N/ by the Raman scattering of spin waves. At the same normalized temperature T/T/sub N/, 1/T/sub 1/ observed in the diluted (Mn/sub 0.5/Zn/sub 0.5/)F/sub 2/ is significantly larger than that in the pure MnF/sub 2/ below T/sub N/. The difference between the pure and diluted systems is related to the large spectral weight of low-energy magnons in (Mn/sub 0.5/Zn/sub 0.5/)F/sub 2/ found by neutron scattering.

  10. HIA 2015 DOE Zero Energy Ready Home Case Study: Evolutionary Home Builders, The Adaptation Home, Geneva, IL

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

    Evolutionary Home Builders The Adaptation Home Geneva, IL DOE ZERO ENERGY READY HOME(tm) The U.S. Department of Energy invites home builders across the country to meet the extraordinary levels of excellence and quality specified in DOE's Zero Energy Ready Home program (formerly known as Challenge Home). Every DOE Zero Energy Ready Home starts with ENERGY STAR Certified Homes Version 3.0 for an energy-efficient home built on a solid foundation of building science research. Advanced technologies

  11. DOE Zero Energy Ready Home Case Study 2013: Weiss Building & Development, LLC., Custom Home, Downer Grove, IL

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

    LLC Custom Home Downers Grove, IL BUILDING TECHNOLOGIES OFFICE The U.S. Department of Energy invites home builders across the country to meet the extraordinary levels of excellence and quality specified in DOE's Zero Energy Ready Home program (formerly known as Challenge Home). Every DOE Zero Energy Ready Home starts with ENERGY STAR for Homes Version 3 for an energy-efficient home built on a solid foundation of building science research. Advanced technologies are designed in to give you

  12. DOE Zero Energy Ready Home Case Study: 2013 Weiss Building & Development, LLC., System Home, River Forest, IL

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

    LLC System Home River Forest, IL BUILDING TECHNOLOGIES OFFICE The U.S. Department of Energy invites home builders across the country to meet the extraordinary levels of excellence and quality specified in DOE's Zero Energy Ready Home program (formerly known as Challenge Home). Every DOE Zero Energy Ready Home starts with ENERGY STAR for Homes Version 3 for an energy-efficient home built on a solid foundation of building science research. Advanced technologies are designed in to give you superior

  13. Effect of organic solvents on particle size of Mn{sub 3}O{sub 4} nanoparticles synthesized by a solvothermal method

    SciTech Connect (OSTI)

    Song, Rui; Feng, Shouhua; Wang, Hongjun; Hou, Changmin

    2013-06-15

    In this paper, a modified simple solvothermal method is employed to synthesize Mn{sub 3}O{sub 4} nanocrystals using four different solvents: acetone, ethanol, N,N-dimethylformamide (DMF), and dimethyl sulfoxide (DMSO). Mn{sub 3}O{sub 4} nanoparticles with a tetragonal hausmannite nano-structure are characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), Fourier transform infrared spectroscopy (FTIR), as well as superconducting quantum interference device magnetometer (SQUID). The Mn{sub 3}O{sub 4} particle size is found to have a strong dependency on the solvent used. A reaction scheme is proposed to understand this dependency, suggesting that the solvent coordinating capability has a critical effect on Mn{sub 3}O{sub 4} particle size. The stronger the coordinating capability of the solvent is, the smaller the Mn{sub 3}O{sub 4} particle size is. In addition, magnetic properties of the nano-structured Mn{sub 3}O{sub 4} are also tested and discussed. - Graphical abstract: The comparison of the particle size of Mn{sub 3}O{sub 4} nanoparticles synthesized using different solvents and HRTEM image of Mn{sub 3}O{sub 4} individual nanoparticle revealed its single-crystal nature. - Highlights: • Mn{sub 3}O{sub 4} nanocrystals were synthesized using different solvents by a solvothermal method. • The particle size of Mn{sub 3}O{sub 4} nanocrystal is found to have a strong dependency on the solvent used. • A reaction mechanism is proposed to explain the difference of particle size of Mn{sub 3}O{sub 4} nanocrystals. • Magnetic properties of Mn{sub 3}O{sub 4} nanocrystals with different particle size are tested and compared.

  14. Facile fabrication of rutile monolayer films consisting of well crystalline nanorods by following an IL-assisted hydrothermal route

    SciTech Connect (OSTI)

    Peng Peng; Liu Xiaodi; Sun, Chuansheng; Ma Jianmin; Zheng Wenjun

    2009-05-15

    In this study, rutile films consisting of rectangular nanorods were facilely deposited on glass substrates from strongly acid solution of TiCl{sub 4}. The highly ordered array of nanorods was realized in presence of ionic liquid (IL) of [Bmim]Br by following a hydrothermal process. In this process, Degussa P25 nanoparticles served as seeds that were pre-deposited on the substrates to facilitate the array of rutile nanorods. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Raman spectrum were used to characterize the obtained nanorod films. The measurements showed that the nanorods were rectangular with width of 100-200 nm and length of more than 1 {mu}m, and grew up typically along c-axis to form the arrays against the substrate. The presence of IL was found vital for the formation of rutile nanorods, and the suitable molar ratio of [Bmim]Br to TiCl{sub 4} ranged from 500:1 to 1500:1. The excessive [Bmim]Br may hinder the precipitation of rutile particles. - Graphical abstract: The rutile film consisting of rectangular nanorods is successfully deposited on glass substrate in presence of ionic liquid (IL) of [Bmim]Br. The nanorods were rectangular with width of 100-200 nm and length of more than 1 {mu}m, which grew up typically along c-axis to form the arrays against the substrate.

  15. Structure and magnetic properties of Ba{sub 5}Ce{sub 1.25}Mn{sub 3.75}O{sub 15}, a new 10H-polytype in the Ba-Ce-Mn-O system

    SciTech Connect (OSTI)

    Macias, Mario A.; Mentre, Olivier; Cuello, Gabriel J.; Gauthier, Gilles H.

    2013-02-15

    Based on the peculiar magnetic properties that are observed in pseudo one-dimensional manganites, we decided to synthesize the new Ba{sub 5}Ce{sub 1.25}Mn{sub 3.75}O{sub 15} compound. The preparation was performed by solid state reaction in air at about 1350 Degree-Sign C, for which we found that the compound crystallizes in a hexagonal symmetry with space group P6{sub 3}/mmc (No-194) and cell parameters a=b=5.7861(2) A and c=23.902(1) A. The structural description was correlated with neutron diffraction and bond valence calculations, confirming the presence of Ce{sup 4+} and Mn{sup 4+} segregated in the different crystallographic positions. Ba{sub 5}Ce{sub 1.25}Mn{sub 3.75}O{sub 15} displays evidence for strong AFM couplings already set at room temperature. The main arrangement of Mn{sup 4+} in magnetically isolated tetramers of face-sharing octahedra is responsible for a metamagnetic-like transition around 50 K. - Graphical abstract: The new Ba{sub 5}Ce{sub 1.25}Mn{sub 3.75}O{sub 15} polytype shows strong AFM couplings in magnetically isolated [Ce{sub 0.25}Mn{sub 3.75}O{sub 15}] tetramers of face-sharing octahedral, resulting in a metamagnetic-like transition around 50 K. Highlights: Black-Right-Pointing-Pointer Ba{sub 5}Ce{sub 1.25}Mn{sub 3.75}O{sub 15}, a new 10H polytype, has been prepared in the Ba-Ce-Mn-O system. Black-Right-Pointing-Pointer The compound crystallizes in the P6{sub 3}/mmc space group with (cchhh){sub 2} stacking sequence. Black-Right-Pointing-Pointer [Ce{sub 0.25}Mn{sub 3.75}O{sub 15}] tetramers are separated by [CeO{sub 6}] octahedra in the structure. Black-Right-Pointing-Pointer Instead of robust AFM ordering, a metamagnetic-like transition is found around 50 K.

  16. IL-2R{gamma} gene microdeletion demonstrates that canine X-linked severe combined immunodeficiency is a homologue of the human disease

    SciTech Connect (OSTI)

    Henthorn, P.S.; Fimiani, V.M.; Patterson, D.F.

    1994-09-01

    X-linked severe combined immunodeficiency (SCID) is characterized by profound defects in cellular and humoral immunity and, in humans, is associated with mutations in the gene for the {gamma} chain of the IL-2 receptor (IL-2R{gamma}). We have examined this gene in a colony of dogs established from a single X-linked SCID carrier female. Affected dogs have a 4-bp deletion in the first exon of the IL-2R{gamma} gene, which precludes the production of a functional protein, demonstrating that the canine disease is a true homologue of human X-linked SCID. 37 refs., 3 figs.

  17. In situ and ex situ spectroelectrochemical and X-ray absorption studies on rechargeable, chemically-modified and other MnO{sub 2} materials

    SciTech Connect (OSTI)

    Conway, B.E.; Qu, D.; McBreen, J. |

    1992-12-31

    A combined series of in situ and ex situ UV spectroelectrochemical and X-ray absorption studies have been made on MnO{sub 2}, chemically-modified by small amounts of Bi(III), and comparatively on other MnO{sub 2} materials such as a blank (Bi-free) and {gamma}-MnO{sub 2}. These procedures are applied in order to follow the oxidation-states of Bi and of Mn during the course of discharge and recharge of MnO{sub 2} as a battery cathode material, and the extents of rechargeability that can be achieved with such materials. Presence of Bi appears to provide a preferred ``heterogeneous`` discharge/recharge pathway involving a soluble Mn(III) intermediate, over the alternative ``electron-proton`` hopping, solid-state mechanism. From XAS results, it is concluded that presence of Bi, although not affecting the O-coordination, does influence the Mn-Mn coordination, determining the way the MnO{sub 2} coordination octahedra are connected.

  18. Mixed metallic Ba(Co,Mn)X{sub 0.2-x}O{sub 3-{delta}} (X=F, Cl) hexagonal perovskites

    SciTech Connect (OSTI)

    Iorgulescu, Mihaela; Roussel, Pascal; Tancret, Nathalie; Renaut, Nicolas; Tiercelin, Nicolas; Mentre, Olivier

    2013-02-15

    We show here that the incorporation of Mn in Ba-Co-oxohalide, BaCoX{sub 0.2-x}O{sub 3-{delta}}, hexagonal perovskite stabilizes the 6H-form (stacking sequence (chhhch Prime ); c, h=[BaO{sub 3}] and h Prime =[BaOX] layers), with tetramers of face-sharing octahedra) rather than the trimeric 10H-form. On the contrary to previous results on the Fe incorporation in similar system leading to more reduced 10H-compounds, the Mn effect is to increase the mean (Co/Mn) valence better suited to the 6H form. We experienced a poor Mn/Co miscibility during our syntheses leading to great difficulties to isolate mixed Co/Mn single phase materials and/or weak reproducibility. Powder neutron diffraction data shows a mixed Mn/Co octahedral occupancy, while the tetrahedra are filled by Co{sup 3+} cations. Anionic vacancies were refined in the h Prime -[BaO{sub 1-z}X{sub 1-x}] layer and the next c-[BaO{sub 3-z}] layers, while the h-[BaO{sub 3}] layers are not oxygen deficient. Magnetic properties suggest that a part of Mn cations remain paramagnetic until low temperature, while isolated spin clusters (probably driven by AFM Co tetrahedral dimers) behave as low-dimensional AFM systems. Transport measurements reveal a transition from high-temperature metallic to low-temperature semi-conducting states that could occur from defect shallow donor upon the Mn for Co substitution. - Graphical abstract: The incorporation of Mn in Ba-Co-oxohalide, BaCoX{sub 0.2-x}O{sub 3-{delta}}, hexagonal perovskite stabilizes the 6H-form with tetrameric (Co,Mn){sub 4}O{sub 15} face sharing linear chains. This results from a oxidizing Mn effect and particular Mn/Co distribution. Highlights: Black-Right-Pointing-Pointer The incorporation of Mn in BaCoX{sub 0.2-x}O{sub 3-{delta}} (X=F,Cl) hexagonal perovskites stabilizes the 6H-form. Black-Right-Pointing-Pointer It contains tetrameric (Co,Mn){sub 4}O{sub 15} face sharing linear chains. Black-Right-Pointing-Pointer The preference for such chains better than

  19. Probing The Electrode/Electrolyte Interface in The Lithium Excess Layered Oxide Li1.2Ni0.2Mn0.6O2

    SciTech Connect (OSTI)

    Carroll, Kyler J; Qian, Danna; Fell, Chris; Calvin, Scott; Veith, Gabriel M; Chi, Miaofang; Dudney, Nancy J; Meng, Ying Shirley

    2013-01-01

    A detailed surface investigation of the lithium-excess nickel manganese layered oxide Li1.2Ni0.2Mn0.6O2 structure was carried out using x-ray photoelectron spectroscopy (XPS), total electron yield and transmission x-ray absorption spectroscopy (XAS), and electron energy loss spectroscopy (EELS) during the first two electrochemical cycles. All spectroscopy techniques consistently showed the presence of Mn4+ in the pristine material and a surprising reduction of Mn at the voltage plateau during the first charge. The Mn reduction is accompanied by the oxygen loss revealed by EELS. Upon the first discharge, the Mn at the surface never fully returns back to Mn4+. The electrode/electrolyte interface of this compound consists of the reduced Mn at the crystalline defect-spinel inner layer and an oxidized Mn species simultaneously with the presence of a superoxide species in amorphous outer layer. This proposed model signifies that oxygen vacancy formation and lithium removal result in electrolyte decomposition and superoxide formation, leading to Mn activation/dissolution and surface layer-spinel phase transformation. The results also indicate that the role of oxygen is complex and significant in contributing to the extra capacity of this class of high energy density cathode materials.

  20. Effect of Mn doping on the structural, optical, and magnetic properties of In{sub 2}O{sub 3} films

    SciTech Connect (OSTI)

    Wang, Shiqi; An, Yukai; Duan, Lingshen; Liu, Huarui; Liu, Jiwen; Wu, Zhonghua

    2013-11-15

    (In{sub 1−x}Mn{sub x}){sub 2}O{sub 3} films were grown by radio frequency-magnetron sputtering technique. Effect of Mn doping on the structural, optical, and magnetic properties of films is investigated systematically. The detailed structure analyses suggest that Mn ions substitute for In{sup 3+} sites of the In{sub 2}O{sub 3} lattice in the valence of +2 states, and Mn-related secondary phases or clusters as the source of ferromagnetism is safely ruled out. All films show typical room temperature ferromagnetism. The saturation magnetization M{sub s} increases first, and then decreases, while carrier concentration n{sub c} decreases monotonically with Mn doping, implying that the ferromagnetism is not directly induced by the mediated carriers. The optical bandgap E{sub g} of films decreases monotonically with the increase of Mn concentration, and there exists a linear functional dependence between E{sub g} and n{sub c}{sup 2/3}, which is consistent with Burstein-Moss shift arguments. It can be concluded that the ferromagnetic order in Mn-doped In{sub 2}O{sub 3} films is intrinsic, arising from Mn atoms substitution for the In sites of In{sub 2}O{sub 3} lattice. The oxygen vacancies play a mediation role on the ferromagnetic couplings between the Mn ions.

  1. Robust antiferromagnetism preventing superconductivity in pressurized (Ba0.61K0.39)Mn2Bi2

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

    Gu, Dachun; Dai, Xia; Le, Congcong; Sun, Liling; Wu, Qi; Saparov, Bayrammurad; Guo, Jing; Gao, Peiwen; Zhang, Shan; Zhou, Yazhou; et al

    2014-12-05

    BaMn2Bi2 possesses an iso-structure of iron pnictide superconductors and similar antiferromagnetic (AFM) ground state to that of cuprates, therefore, it receives much more attention on its properties and is expected to be the parent compound of a new family of superconductors. When doped with potassium (K), BaMn2Bi2 undergoes a transition from an AFM insulator to an AFM metal. Consequently, it is of great interest to suppress the AFM order in the K-doped BaMn2Bi2 with the aim of exploring the potential superconductivity. Here, we report that external pressure up to 35.6 GPa cannot suppress the AFM order in the K-doped BaMn2Bi2more » to develop superconductivity in the temperature range of 300 K–1.5 K, but induces a tetragonal (T) to an orthorhombic (OR) phase transition at ~20 GPa. Theoretical calculations for the T and OR phases, on basis of our high-pressure XRD data, indicate that the AFM order is robust in the pressurized Ba0.61K0.39Mn2Bi2. Utlimately, both of our experimental and theoretical results suggest that the robust AFM order essentially prevents the emergence of superconductivity.« less

  2. Catalytic conversion of syngas to mixed alcohols over Zn-Mn promoted Cu-Fe based catalyst

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

    Lu, Yongwu; Yu, Fei; Hu, Jin; Liu, Jian

    2012-04-12

    Zn-Mn promoted Cu-Fe based catalyst was synthesized by the co-precipitation method. Mixed alcohols synthesis from syngas was studied in a half-inch tubular reactor system after the catalyst was reduced. Zn-Mn promoted Cu-Fe based catalyst was characterized by SEM-EDS, TEM, XRD, and XPS. The liquid phase products (alcohol phase and hydrocarbon phase) were analyzed by GC-MS and the gas phase products were analyzed by GC. The results showed that Zn-Mn promoted Cu-Fe based catalyst had high catalytic activity and high alcohol selectivity. The maximal CO conversion rate was 72%, and the yield of alcohol and hydrocarbons were also very high. Cumore » (111) was the active site for mixed alcohols synthesis, Fe2C (101) was the active site for olefin and paraffin synthesis. The reaction mechanism of mixed alcohols synthesis from syngas over Zn-Mn promoted Cu-Fe based catalyst was proposed. Here, Zn-Mn promoted Cu-Fe based catalyst can be regarded as a potential candidate for catalytic conversion of biomass-derived syngas to mixed alcohols.« less

  3. A study of room-temperature LixMn1.5Ni0.5O4 solid solutions

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

    Saravanan, Kuppan; Jarry, Angelique; Kostecki, Robert; Chen, Guoying

    2015-01-26

    Understanding the kinetic implication of solid-solution vs. biphasic reaction pathways is critical for the development of advanced intercalation electrode materials. Yet this has been a long-standing challenge in materials science due to the elusive metastable nature of solid solution phases. The present study reports the synthesis, isolation, and characterization of room-temperature LixMn1.5Ni0.5O4 solid solutions. In situ XRD studies performed on pristine and chemically-delithiated, micron-sized single crystals reveal the thermal behavior of LixMn1.5Ni0.5O4 (0 ≤ x ≤ 1) cathode material consisting of three cubic phases: LiMn1.5Ni0.5O4 (Phase I), Li0.5Mn1.5Ni0.5O4 (Phase II) and Mn1.5Ni0.5O4 (Phase III). A phase diagram capturing the structuralmore » changes as functions of both temperature and Li content was established. In conclusion, the work not only demonstrates the possibility of synthesizing alternative electrode materials that are metastable in nature, but also enables in-depth evaluation on the physical, electrochemical and kinetic properties of transient intermediate phases and their role in battery electrode performance.« less

  4. Phase transformation during mechano-synthesis of nanocrystalline/amorphous Fe32Mn6Si alloys

    SciTech Connect (OSTI)

    Amini, Rasool; Shamsipoor, Ali; Ghaffari, Mohammad; Alizadeh, Morteza; Okyay, Ali Kemal

    2013-10-15

    Mechano-synthesis of Fe32Mn6Si alloy by mechanical alloying of the elemental powder mixtures was evaluated by running the ball milling process under an inert argon gas atmosphere. In order to characterize the as-milled powders, powder sampling was performed at predetermined intervals from 0.5 to 192 h. X-ray florescence analyzer, X-ray diffraction, scanning electron microscope, and high resolution transmission electron microscope were utilized to investigate the chemical composition, structural evolution, morphological changes, and microstructure of the as-milled powders, respectively. According to the results, the nanocrystalline FeMnSi alloys were completely synthesized after 48 h of milling. Moreover, the formation of a considerable amount of amorphous phase during the milling process was indicated by quantitative X-ray diffraction analysis as well as high resolution transmission electron microscopy image and its selected area diffraction pattern. It was found that the ?-to-? and subsequently the amorphous-to-crystalline (especially martensite) phase transformation occurred by milling development. - Graphical abstract: Mechano-synthesis of nanocrystalline/amorphous Fe32Mn6Si shape memory alloys in the powder form: amorphous phase formation, ?-to-? phase transformation, mechano-crystallization of the amorphous, and martensite phase formation during the process. Highlights: During MA, the ?-to-? phase transformation and amorphization occurred. Mechano-crystallization of the amorphous phase occurred at sufficient milling time. The formation of high amount of ?-martensite was evidenced at high milling times. The platelet, spherical, and then irregular particle shapes was extended by MA. By MA, the particles size was increased, then reduced, and afterward re-increased.

  5. Structural and Chemical Evolution of Li- and Mn-rich Layered Cathode Material

    SciTech Connect (OSTI)

    Zheng, Jianming; Xu, Pinghong; Gu, Meng; Xiao, Jie; Browning, Nigel D.; Yan, Pengfei; Wang, Chong M.; Zhang, Jiguang

    2015-02-24

    Lithium (Li)- and manganese-rich (LMR) layered-structure materials are very promising cathodes for high energy density lithium-ion batteries. However, their voltage fading mechanism and its relationships with fundamental structural changes are far from being sufficiently understood. Here we report the detailed phase transformation pathway in the LMR cathode (Li[Li0.2Ni0.2Mn0.6]O2) during cycling for the samples prepared by hydro-thermal assistant method. It is found the transformation pathway of LMR cathode is closely correlated to its initial structure and preparation conditions. The results reveal that LMR cathode prepared by HA approach experiences a phase transformation from the layered structure to a LT-LiCoO2 type defect spinel-like structure (Fd-3m space group) and then to a disordered rock-salt structure (Fm-3m space group). The voltage fade can be well correlated with the Li ion insertion into octahedral sites, rather than tetrahedral sites, in both defect spinel-like structure and disordered rock-salt structure. The reversible Li insertion/removal into/from the disordered rock-salt structure is ascribed to the Li excess environment that can satisfy the Li percolating in the disordered rock-salt structure despite the increased kinetic barrier. Meanwhile, because of the presence of a great amount of oxygen vacancies, a significant decrease of Mn valence is detected in the cycled particle, which is below that anticipated for a potentially damaging Jahn-Teller distortion (+3.5). Clarification of the phase transformation pathway, cation redistribution, oxygen vacancy and Mn valence change undoubtedly provides insights into a profound understanding on the voltage fade, and capacity degradation of LMR cathode. The results also inspire us to further enhance the reversibility of LMR cathode via improving its surface structural stability.

  6. Generation and control of spin-polarized photocurrents in GaMnAs heterostructures

    SciTech Connect (OSTI)

    Bezerra, Anibal T. Farinas, Paulo F.; Studart, Nelson; Degani, Marcos H.; Maialle, Marcelo Z.

    2014-01-13

    Photocurrents are calculated for a specially designed GaMnAs semiconductor heterostructure. The results reveal regions in the infrared range of the energy spectrum, in which the proposed structure is remarkably spin-selective. For such photon energies, the generated photocurrents are strongly spin-polarized. Application of a relatively small static bias in the growth direction of the structure is predicted to efficiently reverse the spin-polarization for some photon energies. This behavior suggests the possibility of conveniently simple switching mechanisms. The physics underlying the results is studied and understood in terms of the spin-dependent properties emerging from the particular potential profile of the structure.

  7. Magnetic and transport properties of Mn{sub 2}CoAl oriented films

    SciTech Connect (OSTI)

    Jamer, Michelle E.; Assaf, Badih A.; Devakul, Trithep; Heiman, Don

    2013-09-30

    The structure, magnetic, and transport properties of thin films of the Heusler ferrimagnet Mn{sub 2}CoAl have been investigated for properties related to spin gapless semiconductors. Oriented films were grown by molecular beam epitaxy on GaAs substrates and the structure was found to transform from tetragonal to cubic for increasing annealing temperature. The anomalous Hall resistivity is found to be proportional to the square of the longitudinal resistivity and magnetization expected for a topological Berry curvature origin. A delicate balance of the spin-polarized carrier type when coupled with voltage gate-tuning could significantly impact advanced electronic devices.

  8. Magnetic domain wall manipulation in (Ga,Mn)As nanostructures for spintronic applications

    SciTech Connect (OSTI)

    Wosinski, Tadeusz; Andrearczyk, Tomasz; Figielski, Tadeusz; Olender, Karolina; Wrobel, Jerzy

    2014-02-21

    Ring-shaped nanostructures have been designed and fabricated by electron-beam lithography patterning and chemical etching from thin epitaxial layers of the ferromagnetic semiconductor (Ga,Mn)As. The nanostructures, in a form of planar rings with a slit, were supplied with four electrical terminals and subjected to magneto-transport studies under planar weak magnetic field. Magnetoresistive effects caused by manipulation of magnetic domain walls and magnetization reversal in the nanostructures have been investigated and possible applications of the nanostructures as four-terminal spintronic devices are discussed.

  9. Magnetocrystalline anisotropy in UMn2Ge2 and related Mn-based actinide ferromagnets

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

    Parker, David S.; Ghimire, Nirmal; Singleton, John; Thompson, J. D.; Bauer, Eric D.; Baumbach, Ryan; Mandrus, David; Li, Ling; Singh, David J.

    2015-05-04

    We presenmore » t magnetization isotherms in pulsed magnetic fields up to 62 Tesla, supported by first principles calculations, demonstrating a huge uniaxial magnetocrystalline anisotropy energy - approximately 20 MJ/m3 - in UMn2Ge2. This large anisotropy results from the extremely strong spin-orbit coupling affecting the uranium 5 f electrons, which in the calculations exhibit a substantial orbital moment exceeding 2 μB. Finally, we also find from theoretical calculations that a number of isostructural Mn-actinide compounds are expected to have similarly large anisotropy.« less

  10. Magnetocrystalline Anisotropy in UMn2Ge2 and Related Mn-based Actinide Ferromagnets

    SciTech Connect (OSTI)

    Parker, David S; Mandrus, D.; Ghimire, N J; Baumbach, Ryan; Singleton, John; Thompson, J.D.; Bauer, Eric D.; Li, Ling; Singh, David J

    2015-01-01

    We present magnetization isotherms in pulsed magnetic fields up to 62 Tesla, supported by first principles calculations, demonstrating a huge uniaxial magnetocrystalline anisotropy energy - approximately 20 MJ/m3 - in UMn2Ge2. This large anisotropy results from the extremely strong spin-orbit coupling affecting the uranium 5 f electrons, which in the calculations exhibit a substantial orbital moment exceeding 2 Bohr magnetons. We also find from theoretical calculations that a number of isostructural Mn-actinide compounds are expected to have similarly large anisotropy.

  11. Spin Hall effect-controlled magnetization dynamics in NiMnSb

    SciTech Connect (OSTI)

    Dürrenfeld, P. Ranjbar, M.; Gerhard, F.; Gould, C.; Molenkamp, L. W.; Åkerman, J.

    2015-05-07

    We investigate the influence of a spin current generated from a platinum layer on the ferromagnetic resonance (FMR) properties of an adjacent ferromagnetic layer composed of the halfmetallic half-Heusler material NiMnSb. Spin Hall nano-oscillator devices are fabricated, and the technique of spin torque FMR is used to locally study the magnetic properties as in-plane anisotropies and resonance fields. A change in the FMR linewidth, in accordance with the additional spin torque produced by the spin Hall effect, is present for an applied dc current. For sufficiently large currents, this should yield auto-oscillations, which however are not achievable in the present device geometry.

  12. Vacancy dynamic in Ni-Mn-Ga ferromagnetic shape memory alloys

    SciTech Connect (OSTI)

    Merida, D.; Snchez-Alarcos, V.; Prez-Landazbal, J. I.; Recarte, V.; Plazaola, F.

    2014-06-09

    Vacancies control any atomic ordering process and consequently most of the order-dependent properties of the martensitic transformation in ferromagnetic shape memory alloys. Positron annihilation spectroscopy demonstrates to be a powerful technique to study vacancies in NiMnGa alloys quenched from different temperatures and subjected to post-quench isothermal annealing treatments. Considering an effective vacancy type the temperature dependence of the vacancy concentration has been evaluated. Samples quenched from 1173?K show a vacancy concentration of 1100??200?ppm. The vacancy migration and formation energies have been estimated to be 0.55??0.05?eV and 0.90??0.07?eV, respectively.

  13. Direct evidence of detwinning in polycrystalline Ni-Mn-Ga ferromagnetic shape memory alloys during deformation.

    SciTech Connect (OSTI)

    Nie, Z. H.; Lin Peng, R.; Johansson, S.; Oliver, E. C.; Ren, Y.; Wang, Y. D.; Liu, Y. D.; Deng, J. N.; Zuo, L.; Brown, D. E.; Northwestern Univ., China; Linkoping Univ.; Rutherford Appleton Lab.; Northern Illinois Univ.

    2008-01-01

    In situ time-of-flight neutron diffraction and high-energy x-ray diffraction techniques were used to reveal the preferred reselection of martensite variants through a detwinning process in polycrystalline Ni-Mn-Ga ferromagnetic shape memory alloys under uniaxial compressive stress. The variant reorientation via detwinning during loading can be explained by considering the influence of external stress on the grain/variant orientation-dependent distortion energy. These direct observations of detwinning provide a good understanding of the deformation mechanisms in shape memory alloys.

  14. Magnetoelastic Coupling and Symmetry Breaking in the Frustrated Antiferromagnet {alpha}-NaMnO{sub 2}

    SciTech Connect (OSTI)

    Giot, Maud; Chapon, Laurent C.; Radaelli, Paolo G.; Androulakis, John; Lappas, Alexandros; Green, Mark A.

    2007-12-14

    The magnetic and crystal structures of the {alpha}-NaMnO{sub 2} have been determined by high-resolution neutron powder diffraction. The system maps out a frustrated triangular spin lattice with anisotropic interactions that displays two-dimensional spin correlations below 200 K. Magnetic frustration is lifted through magneto-elastic coupling, evidenced by strong anisotropic broadening of the diffraction profiles at high temperature and ultimately by a structural phase transition at 45 K. In this low-temperature regime a three-dimensional antiferromagnetic state is observed with a propagation vector k=((1/2),(1/2),0)

  15. Half metallic ferromagnetism in alkali metal nitrides MN (M = Rb, Cs): A first principles study

    SciTech Connect (OSTI)

    Murugan, A. Rajeswarapalanichamy, R. Santhosh, M. Sudhapriyanga, G.; Kanagaprabha, S.

    2014-04-24

    The structural, electronic and elastic properties of two alkali metal nitrides (MN: M= Rb, Cs) are investigated by the first principles calculations based on density functional theory using the Vienna ab-initio simulation package. At ambient pressure the two nitrides are stable in ferromagnetic state with CsCl structure. The calculated lattice parameters are in good agreement with the available results. The electronic structure reveals that these materials are half metallic in nature. A pressure-induced structural phase transition from CsCl to ZB phase is observed in RbN and CsN.

  16. Neutron structural characterization, inversion degree and transport properties of NiMn{sub 2}O{sub 4} spinel prepared by the hydroxide route

    SciTech Connect (OSTI)

    Sagua, A.; Lescano, Gabriela M.; Alonso, J.A.; Martínez-Coronado, R.; Fernández-Díaz, M.T.; Morán, E.

    2012-06-15

    Graphical abstract: A pure specimen has been synthesized by the hydroxide route. This spinel, studied by NPD, shows an important inversion degree, λ = 0.80. A bond-valence study shows that the tetrahedral Mn ions are divalent whereas the octahedral Mn and Ni are slightly oxidized from the expected 3+ and 2+ values, respectively. The mixed valence Mn{sup 3+}/Mn{sup 4+} accounts for a hopping mechanism between adjacent octahedral sites, leading to a significant conductivity. Highlights: ► A low-temperature hydroxide route allowed preparing almost pure specimens of NiMn{sub 2}O{sub 4}. ► NPD essential to determine inversion degree; contrasting Ni and Mn for neutrons. ► Bond valence establishes valence state of octahedral and tetrahedral Ni and Mn ions. ► Thermal analysis, transport measurements complement characterization of this oxide. ► A structure–properties relationship is established. -- Abstract: The title compound has been synthesized by the hydroxide route. The crystal structure has been investigated at room temperature from high-resolution neutron powder diffraction (NPD) data. It crystallizes in a cubic spinel structure, space group Fd3{sup ¯}m, Z = 8, with a = 8.3940(2) Å at 295 K. The crystallographic formula is (Ni{sub 0.202(1)}Mn{sub 0.798(1)}){sub 8a}(Ni{sub 0.790(1)}Mn{sub 1.210(1)}){sub 16d}O{sub 4} where 8a and 16d stand for the tetrahedral and octahedral sites of the spinel structure, respectively. There is a significant inversion degree of the spinel structure, λ = 0.80. In fact, the variable parameter for the oxygen position, u = 0.2636(4), is far from that expected (u = 0.25) for normal spinels. From a bond-valence study, it seems that the valence distribution in NiMn{sub 2}O{sub 4} spinel is not as trivial as expected (Ni{sup 2+} and Mn{sup 3+}), but clearly the tetrahedral Mn ions are divalent whereas the octahedral Mn and Ni are slightly oxidized from the expected +3 and +2 values, respectively. The mixed valence observed at

  17. Investigation on structural, optical and magnetic properties of double perovskite Gd{sub 2}NiMnO{sub 6}

    SciTech Connect (OSTI)

    Mohapatra, S. R.; Sahu, B.; Raut, S.; Singh, A. K.; Kaushik, S. D.

    2015-06-24

    Single phase double perovskite Gd{sub 2}NiMnO{sub 6} was prepared by conventional solid state reaction route. X-ray diffraction (XRD) result reveals that the compound possess monoclinic structure with space group P2{sub 1}/n. Optical characterization performed at room temperature via UV-visible spectroscopy confirms Gd{sub 2}NiMnO{sub 6} as a direct band-gap material with band gap of ∼1.5 eV. Magnetization measurement in Zero field cooled (ZFC) condition at H = 100 Oe shows magnetic transition at ∼ 125 K. Due to competing interactions between magnetic ions (Ni{sup 2+} and Mn{sup 4+}), we could observe two magnetic transition below 40 K.

  18. Depth-dependent magnetism in epitaxial MnSb thin films: effects of surface passivation and cleaning

    SciTech Connect (OSTI)

    Aldous J. D.; Sanchez-Hanke C.; Burrows, C.W.; Maskery, I.; Brewer, M.S.; Hase, T.P.A.; Duffy, J.A.; Lees, M. Rs; Decoster, T.; Theis, W.; Quesada, A.; Schmid, A.K.; Bell, G.R.

    2012-03-15

    Depth-dependent magnetism in MnSb(0001) epitaxial films has been studied by combining experimental methods with different surface specificities: polarized neutron reflectivity, x-ray magnetic circular dichroism (XMCD), x-ray resonant magnetic scattering and spin-polarized low energy electron microscopy (SPLEEM). A native oxide {approx}4.5 nm thick covers air-exposed samples which increases the film's coercivity. HCl etching efficiently removes this oxide and in situ surface treatment of etched samples enables surface magnetic contrast to be observed in SPLEEM. A thin Sb capping layer prevents oxidation and preserves ferromagnetism throughout the MnSb film. The interpretation of Mn L{sub 3,2} edge XMCD data is discussed.

  19. Site preference and compensation behavior in Co(Cr, Mn){sub 2}O{sub 4} system

    SciTech Connect (OSTI)

    Zhang, H. G.; Wang, Z.; Yue, M.; Liu, E. K.; Wang, W. H.; Wu, G. H.

    2015-05-07

    Site preference of doped Mn ions in CoCr{sub 2−x}Mn{sub x}O{sub 4} (x = 0–2) series has been derived separately from structure and magnetic measurement. It shows that parts of the doped Mn ions occupy the A (Co) sites when x < 0.5. And then, it takes the two B (Cr) sites in turn before and after x = 1.3. This site preference behavior results in a role conversion of the magnetic contributors and, thus, leads to the composition dependent magnetic compensation. Temperature induced compensation and negative magnetization have also been found in several samples, which is attributed to the large energy barrier between the ferromagnetic and antiferromagnetic spin arrangement. A structure transition from cubic to tetragonal symmetry has been detected.

  20. Calculations of structural, elastic, electronic, magnetic and phonon properties of FeNiMnAl by the first principles

    SciTech Connect (OSTI)

    U?ur, ?ule; ?yigr, Ahmet

    2014-10-06

    The electronic, elastic and dynamical properties of the quaternary alloy FeNiMnAl have been investigated using a pseudopotential plane wave method within the generalized gradient approximation (GGA). We determined the lattice parameters and the bulk modulus B. In addition, the elastic properties such as elastic constans (C{sub 11}, C{sub 12} and C{sub 44}), the shear modulus G, the young modulus E, the poisson's ratio ? and the B/G ratio are also given. The FeNiMnAl Heusler alloy exhibit a ferromagnetic half-metallic behavior with the total magnetic moment of 4.02 ?{sub B}. The phonon dispersion of FeNiMnAl has been performed using the density functional theory and the direct method with 222 supercell.

  1. Electronic phase separation in lanthanum manganites: Evidence from {sup 55}Mn NMR

    SciTech Connect (OSTI)

    Allodi, G.; De Renzi, R.; Guidi, G.; Licci, F.; Pieper, M.W.

    1997-09-01

    {sup 55}Mn NMR experiments were carried out at 1.3{endash}4.2 K on six samples of lanthanum manganites, with a hole doping concentration ranging from the antiferromagnetic-insulator to the ferromagnetic-conductor region of the phase diagram. The dependence of the resonance frequencies on external fields is either as expected for ferromagnets (FM) or for antiferromagnets (AF). No indication of a canted phase could be detected. FM and AF resonances were found to coexist in all samples and are grouped in three broad bands, whose frequencies do not depend in first order on hole concentration. Strong evidence of interaction between AF and FM regions was provided by longitudinal relaxation experiments in several samples. An explanation of this behavior is offered in terms of intrinsic phase separation of the holes into FM microdomains. We determine the {sup 55}Mn hyperfine coupling to be isotropic in all cases, with A=6.2T/{mu}{sub B} for the on-site term in the AF domains. {copyright} {ital 1997} {ital The American Physical Society}

  2. Itinerant Antiferromagnetism in FeMnP0.8Si0.2

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

    Sales, Brian C.; Susner, Michael A.; Conner, Benjamin S.; Yan, Jiaqiang Q.; May, Andrew F.

    2015-09-25

    Compounds based on the Fe2P structure have continued to attract interest because of the interplay between itinerant and localized magnetism in a noncentrosymmetric crystal structure, and because of the recent developments of these materials for magnetocaloric applications. We report the growth and characterization of millimeter-sized single crystals of FeMnP0.8Si0.2 with the Fe2P structure. Single-crystal x-ray diffraction, magnetization, resistivity, and Hall and heat capacity data are reported. The crystals exhibit itinerant antiferromagnetic order below 158 K with no hint of ferromagnetic behavior in the magnetization curves and with the spins ordered primarily in the ab plane. The room-temperature resistivity is closemore » to the Ioffe-Regel limit for a metal. Single-crystal x-ray diffraction indicates a strong preference for Mn to occupy the larger pyramidal 3g site. The cation site preference in the as-grown crystals and the antiferromagnetism were not changed after high-temperature anneals and a rapid quench to room temperature« less

  3. Nanofiber of Mn{sub 3}O{sub 4}: Fabrication and application as supercapacitor electrode

    SciTech Connect (OSTI)

    Bhagwan, Jai; Sharma, Yogesh; Yadav, K. L.

    2015-06-24

    Mn{sub 3}O{sub 4}–nanofiber with high aspect ratio is prepared by a simple electrospinning process. The thermal, structural and morphological characterizations are carried out by TGA, XRD and FESEM, respectively. To assess the property of nanofiber for the use in supercapacitors, cyclic voltammetry (CV) and galvanostatic charging-discharging (GCD) are performed in 2M KOH electrolyte with the potential window ranging from +0.42V to −0.45V. Effect of polymer concentration and electric field intensity on the diameter of as-spun nanofiber was studied. Further, appropriate heating rate was used for sintering to obtain aligned nanofiber. High specific capacitance of 150(±5) F g{sup −1} is obtained by Mn{sub 3}O{sub 4} nanofibers. The rate performance is also found to be good. This improved performance in terms of high specific capacitance and rate capability is ascribed to the nanofabric morphology which provides more active sites and easy access path for ions/electrons.

  4. Thermochemical generation of hydrogen and oxygen from water. [NaMnO/sub 2/ and TiO/sub 2/

    DOE Patents [OSTI]

    Robinson, P.R.; Bamberger, C.E.

    1980-02-08

    A thermochemical cyclic process for the production of hydrogen exploits the reaction between sodium manganate (NaMnO/sub 2/) and titanium dioxide (TiO/sub 2/) to form sodium titanate (Na/sub 2/TiO/sub 3/), manganese (II) titanate (MnTiO/sub 3/) and oxygen. The titanate mixture is treated with sodium hydroxide, in the presence of steam, to form sodium titanate, sodium manganate (III), water and hydrogen. The sodium titanate-manganate (III) mixture is treated with water to form sodium manganate (III), titanium dioxide and sodium hydroxide. Sodium manganate (III) and titanium dioxide are recycled following dissolution of sodium hydroxide in water.

  5. Influence of defects on the structural and magnetic properties of multifunctional La2NiMnO6 thin films

    SciTech Connect (OSTI)

    Guo, HZ; Burgess, J; Ada, E; Street, S; Gupta, A.; Iliev, M N; Kellock, A J; Magen Dominguez, Cesar; Varela del Arco, Maria; Pennycook, Stephen J

    2008-01-01

    Thin films of the double perovskite La2NiMnO6 (LNMO) have been grown on various lattice-matched substrates (SrTiO3, LaAlO3, NdGaO3 and MgO) by pulsed laser deposition under varying oxygen background pressure (25 - 800 mTorr). The out-of-plane lattice constant of the LNMO film initially decreases with increasing pressure, likely caused by a reduction in the defect concentration and improved structural ordering, before leveling off at higher pressures. Scanning transmission electron microscopy results show that the films are epitaxial, and the interface is sharp and coherent. While very few defects are observed by STEM in a film grown at high oxygen pressure (800 mTorr), a film grown at a lower pressure (100 mTorr) shows the formation of defects that extend throughout the thickness except for a very thin layer near the interface. The Raman spectra of the films are dominated by two broad peaks at around 540 cm-1 and 685 cm-1, which are assigned to the antisymmetric stretching (AS) and symmetric stretching (S) modes of MnO6 and NiO6 octahedra, respectively. The Raman peaks of the LNMO thin films grown in 800 mTorr background O2 are blue shifted in comparison to those of LNMO bulk, and the shift increases with decreasing film thickness, indicating the increased influence of strain. The critical thickness for strain relaxation as determined from the Raman spectra is between 40 - 80 nm. The strain is observed to have a negligible influence on the magnetic properties for films grown at high oxygen pressures. However, films grown at low pressures exhibit degraded magnetic properties, which can be attributed to a combination of B-site cation disorder and an increase in the concentration of Mn3+ and Ni3+ Jahn-Teller ions caused by oxygen defects. With increasing oxygen pressure during growth, the paramagnetic-ferromagnetic transition temperature (~280 K) gets sharper and the saturation magnetization at low temperatures is enhanced. Based on electron energy loss spectroscopy

  6. Spectroscopic and magnetic properties of Mn doped GaN epitaxial films grown by plasma assisted molecular beam epitaxy

    SciTech Connect (OSTI)

    Vidyasagar, R.; Lin, Y.-T.; Tu, L.-W.

    2012-12-15

    Graphical abstract: We report here that micro-Raman scattering spectrum for Mn doped GaN thin film has displayed a new peak manifested at 578 cm{sup −1}, by which it is attributed to interior LVM originated by the incorporation of Mn ions in place of Ga sites. Mn doped GaN thin film also showed the typical negative magnetoresistance up to ∼50 K, revealing that the film showed magnetic ordering of spins below 50 K. Display Omitted Highlights: ► GaN and Mn doped GaN single phase wurtzite structures grown by PAMBE. ► The phase purity of the epilayers investigated by HRXRD, HRSEM and EDX. ► The red shift in near band edge emission has been observed using micro-PL. ► A new peak related LVM at 578 cm{sup −1} in micro-Raman scattering measurements confirmed Mn doped into GaN. ► Negative-magnetoresistance investigations have showed that the film has T{sub c} < 50 K. -- Abstract: Spectroscopic and magnetic properties of Mn doped GaN, and GaN epitaxial films have been investigated by employing micro-photoluminescence, micro-Raman, and temperature dependent magneto-resistance measurements. The HR-XRD profiles have shown that the epitaxial films are in hexagonal wurtzite structures. Morphology and composition of the films have been examined by field emission scanning electron microscopy, and energy-dispersive X-ray analysis. Micro-photoluminescence spectrum displayed a dominant near band edge emission at 362 nm, which is assigned to near band edge transition within the hexagonal structure of GaN. Raman scattering profiles showed a new vibrational mode at 578 cm{sup −1}, which is attributed to the vacancy-related local vibrational mode of Mn occupying the Ga site. Temperature dependent negative magnetoresistance measurements provide a direct evidence of magnetic ordering below 50 K for the Mn doped GaN thin film.

  7. Suppression of the thermal hysteresis in magnetocaloric MnAs thin film by highly charged ion bombardment

    SciTech Connect (OSTI)

    Trassinelli, M. Marangolo, M.; Eddrief, M.; Etgens, V. H.; Gafton, V.; Hidki, S.; Lacaze, E.; Lamour, E.; Prigent, C.; Rozet, J.-P.; Steydli, S.; Zheng, Y.; Vernhet, D.

    2014-02-24

    We present the investigation on the modifications of structural and magnetic properties of MnAs thin film epitaxially grown on GaAs induced by slow highly charged ions bombardment under well-controlled conditions. The ion-induced defects facilitate the nucleation of one phase with respect to the other in the first-order magneto-structural MnAs transition, with a consequent suppression of thermal hysteresis without any significant perturbation on the other structural and magnetic properties. In particular, the irradiated film keeps the giant magnetocaloric effect at room temperature opening new perspective on magnetic refrigeration technology for everyday use.

  8. A determination of the oxygen non-stoichiometry of the oxygen storage material YBaMn{sub 2}O{sub 5+δ}

    SciTech Connect (OSTI)

    Jeamjumnunja, Kannika; Gong, Wenquan; Makarenko, Tatyana; Jacobson, Allan J.

    2015-10-15

    The A-site ordered double-perovskite oxide, YBaMn{sub 2}O{sub 5+δ}, has been of recent interest for possible application as an oxygen storage material. In the present study, the oxygen non-stoichiometry of YBaMn{sub 2}O{sub 5+δ} has been determined as a function of pO{sub 2} at 650, 700 and 750 °C by Coulometric titration at near-equilibrium conditions. The results confirm that this perovskite oxide has three distinct phases on oxidation/reduction with δ≈0, 0.5 and 1. The stabilities of the YBaMn{sub 2}O{sub 5+δ} phases span a wide range of oxygen partial pressures (∼10{sup −20}≤pO{sub 2}(atm)≤∼1 ) depending on temperature. The phases interconvert at higher pO{sub 2} values at higher temperatures. The partial molar free energies (Δμ{sub O}) corresponding to the oxidation of YBaMn{sub 2}O{sub 5} to YBaMn{sub 2}O{sub 5.5} and of YBaMn{sub 2}O{sub 5.5} to YBaMn{sub 2}O{sub ∼6} were determined. The value of Δμ{sub O} in both oxidation steps becomes less negative with increasing temperature. At some T and pO{sub 2} conditions, YBaMn{sub 2}O{sub 5+δ} is unstable with respect to decomposition to BaMnO{sub 3−δ} and YMnO{sub 3}. This instability is anticipated from the previous studies of the synthesis of YBaMn{sub 2}O{sub 5+δ} but is more apparent in the present experiments which are necessarily slow in order to achieve equilibrium with respect to the oxygen content. - Highlights: • Determination of the oxygen non-stoichiometry of YBaMn{sub 2}O{sub 5+δ} as a function of pO{sub 2} and T. • Establishments of pO{sub 2} ranges of stability of O{sub 5} and O{sub 5.5} at 650 °C, 700 °C and 750 °C. • Discovery of the kinetic instability of YBaMn{sub 2}O{sub 5+δ} with respect to decomposition to BaMnO{sub 3}−{sub x} and YMnO{sub 3}. • Evaluation of the thermodynamics of the oxidation of YBaMnO{sub 5}.

  9. HIA 2015 DOE Zero Energy Ready Home Case Study: BrightLeaf Homes, McCormick Avenue, Brookfield, IL

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

    BrightLeaf Homes McCormick Avenue Brookfield, IL DOE ZERO ENERGY READY HOME(tm) The U.S. Department of Energy invites home builders across the country to meet the extraordinary levels of excellence and quality specified in DOE's Zero Energy Ready Home program (formerly known as Challenge Home). Every DOE Zero Energy Ready Home starts with ENERGY STAR Certified Homes Version 3.0 for an energy-efficient home built on a solid foundation of building science research. Advanced technologies are

  10. Electronic and magnetic properties of double perovskite Dy{sub 2}MnCoO{sub 6} by first-principles calculation

    SciTech Connect (OSTI)

    Ganeshraj, C.; Santhosh, P. N.

    2014-05-07

    Using first-principles calculation, we investigate electronic and magnetic properties of Dy{sub 2}MnCoO{sub 6}. A detailed structural optimization has been done and found that the orthorhombic structure with Mn (Co) ions aligning along the longest axis type is the most stable structure. Within the generalized gradient approximation, the spin polarized calculations predict Dy{sub 2}MnCoO{sub 6} to be a half-metallic with ferromagnetic interaction between Mn and Co ions and antiferromagnetic interaction between Dy and Mn/Co ions. We also investigate the effect of Hubbard parameter (U) on the ground state magnetic structure. For all values of Hubbard U parameter the Co ions have nonzero magnetic moment; they do not lie in low-spin state, as in DyCoO{sub 3}.

  11. Electrochemically induced deposition method to prepare {gamma}-MnO{sub 2}/multi-walled carbon nanotube composites as electrode material in supercapacitors

    SciTech Connect (OSTI)

    Fan Zhen

    2008-08-04

    The {gamma}-MnO{sub 2}/multi-walled carbon nanotube ({gamma}-MnO{sub 2}/MWNT) composite has been prepared by electrochemically induced deposition method. The morphology and crystal structure of the composite were investigated by X-ray diffraction and scanning electron microscopy, respectively. The capacitive properties of the {gamma}-MnO{sub 2}/MWNT composite have been investigated by cyclic voltammetry (CV). A specific capacitance (based on {gamma}-MnO{sub 2}) as high as 579 F g{sup -1} is obtained at a scan rate of 10 mV s{sup -1} in 0.1 M Na{sub 2}SO{sub 4} aqueous solution. Additionally, the {gamma}-MnO{sub 2}/MWNT composite electrode shows excellent long-term cycle stability (only 2.4% decrease of the specific capacitance is observed after 500 CV cycles)

  12. CdSe/ZnSe quantum dot with a single Mn{sup 2+} ionA new system for a single spin manipulation

    SciTech Connect (OSTI)

    Smole?ski, T.

    2015-03-21

    We present a magneto-optical study of individual self-assembled CdSe/ZnSe quantum dots doped with single Mn{sup 2+} ions. Properties of the studied dots are analyzed analogously to more explored system of Mn-doped CdTe/ZnTe dots. Characteristic sixfold splitting of the neutral exciton emission line as well as its evolution in the magnetic field are described using a spin Hamiltonian model. Dynamics of both exciton recombination and Mn{sup 2+} spin relaxation are extracted from a series of time-resolved experiments. Presence of a single dopant is shown not to affect the average excitonic lifetime measured for a number of nonmagnetic and Mn-doped dots. On the other hand, non-resonant pumping is demonstrated to depolarize the Mn{sup 2+} spin in a quantum dot placed in external magnetic field. This effect is utilized to determine the ion spin relaxation time in the dark.

  13. Induced Ti magnetization at La0.7Sr0.3MnO3 and BaTiO3 interfaces

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

    Liu, Yaohua; Tornos, J.; te Velthuis, S. G. E.; Freeland, J. W.; Zhou, H.; Steadman, P.; Bencok, P.; Leon, C.; Santamaria, J.

    2016-04-01

    In artificial multiferroics hybrids consisting of ferromagnetic La0.7Sr0.3MnO3 (LSMO) and ferroelectric BaTiO3 epitaxial layers, net Ti moments are found from polarized resonant soft x-ray reflectivity and absorption. Moreover, the Ti dichroic reflectivity follows the Mn signal during the magnetization reversal, indicating exchange coupling between the Ti and Mn ions. But, the Ti dichroic reflectivity shows stronger temperature dependence than the Mn dichroic signal. Besides a reduced ferromagnetic exchange coupling in the interfacial LSMO layer, this may also be attributed to a weak Ti-Mn exchange coupling that is insufficient to overcome the thermal energy at elevated temperatures.

  14. Radiation-induced instability of MnS precipitates and its possible consequences on irradiation-induced stress corrosion cracking of austenitic stainless steels

    SciTech Connect (OSTI)

    Chung, H.M.; Sanecki, J.E.; Garner, F.A.

    1996-12-01

    Irradiation-assisted stress corrosion cracking (IASCC) is a significant materials issue for the light water reactor (LWR) industry and may also pose a problem for fusion power reactors that will use water as coolant. A new metallurgical process is proposed that involves the radiation-induced release into solution of minor impurity elements not usually thought to participate in IASCC. MnS-type precipitates, which contain most of the sulfur in stainless steels, are thought to be unstable under irradiation. First, Mn transmutes strongly to Fe in thermalized neutron spectra. Second, cascade-induced disordering and the inverse Kirkendall effect operating at the incoherent interfaces of MnS precipitates are thought to act as a pump to export Mn from the precipitate into the alloy matrix. Both of these processes will most likely allow sulfur, which is known to exert a deleterious influence on intergranular cracking, to re-enter the matrix. To test this hypothesis, compositions of MnS-type precipitates contained in several unirradiated and irradiated heats of Type 304, 316, and 348 stainless steels (SSs) were analyzed by Auger electron spectroscopy. Evidence is presented that shows a progressive compositional modification of MnS precipitates as exposure to neutrons increases in boiling water reactors. As the fluence increases, the Mn level in MnS decreases, whereas the Fe level increases. The S level also decreases relative to the combined level of Mn and Fe. MnS precipitates were also found to be a reservoir of other deleterious impurities such as F and O which could be also released due to radiation-induced instability of the precipitates.

  15. Activation of IL-2 receptor {alpha}-chain gene by individual members of the rel oncogene family in association with serum response factor

    SciTech Connect (OSTI)

    Pierce, J.W.; Jamieson, C.A.; Ross, J.L.

    1995-08-15

    Expression of the IL-2R{alpha} gene is regulated by members of the c-Rel/NF-{kappa}B family of transcription factors binding to the {kappa}B site in the promoter. Previous work has not defined the role of individual members of the c-Rel family in the activation of the IL-2R{alpha} gene. Using the COS cell system, we were able to reconstitute the regulation of the IL-2R{alpha} promoter by expressing cloned Rel family members with serum response factor (SRF). We found that c-rel alone activated the IL-2R{alpha} promoter only weakly but worked with the p50 subunit of NF-{kappa}B (NFKB1) to give a higher level of expression. We showed that c-rel heterodimerizes with p50 and the amount of this heterodimer correlated with the level of IL-2R{alpha} gene expression. Our results provide evidence that c-rel/p50 heterodimers activate gene expression in the context of a cellular promoter. We show that c-rel or p65 can cooperate with SRF in the activation of this promoter and the transactivation by c-rel with SRF was enhanced by p50. Synergistic activation required both {kappa}B an CArG sites, and binding studies show that these that these adjacent sites can be occupied simultaneously. The transactivation observed with cloned transcription factors mimics the physiologic induction of the IL-2R{alpha} gene since multiple sequence elements cooperate to give gene activation. The data support the model that c-rel/p50 or p65 can cooperate with SRF to specifically target the expression of the IL-2R{alpha} gene in activated T cells.

  16. KINETICS OF Mn-BASED SORBENTS FOR HOT COAL GAS DESULFURIZATION

    SciTech Connect (OSTI)

    K.A. SADECKI; M.T. HEPWORTH

    1997-06-15

    Manganese-based sorbents have been investigated for the removal of hydrogen sulfide (the primary sulfur bearing compound) from hot coal gases. Four formulations of Mn-based sorbents were tested in an ambient-pressure fixed-bed reactor to determine steady state H2S concentrations, breakthrough times and effectiveness of the sorbent when subjected to cyclic sulfidation and regeneration testing. In previous reports, the sulfidation and regeneration results from cyclic testing done at 550 and 600 °C were presented. Manganese-based sorbents with molar ratios > 1:1 Mn:Substrate were effective in reducing the H2S concentration in simulated coal gases to less than 100 ppmv over five cycles. Actual breakthrough time for formulation C6-2-1100 was as high as 73% of breakthrough time based on wt% Mn in sorbent at 600 °C. Regeneration tests determined that loaded pellets can be essentially completely regenerated in air/steam mixture at 750 °C with minimal sulfate formation. In this report, the performance of the leading formulation (designated C6-2) was investigated for high temperature removal of H2S from simulated coal-derived fuel gas under varying sorbent induration temperature, reaction temperature, and superficial gas velocity. Sulfidation experiments were performed in an ambient pressure fixed-bed reactor between 500 °C and 600 °C. Four tests were conducted with each test consisting of four cycles of sulfidation and regeneration. Results showed that the induration temperature of the sorbent and the reaction temperature greatly affected the H2S removal capacity of the sorbent while the superficial gas velocity between 1090 and 1635 cm/min had minimal affect on the sorbent's breakthrough capacity. Sorbent also showed 30 to 53% loss of its strength over four cycles of sulfidation and regeneration. The former being sorbent indurated at 1115 °C and the prior being sorbent indurated at 1100 °C.

  17. Removal of Ca2+ from the Oxygen-Evolving Complex in Photosystem II Has Minimal Effect on the Mn4O5 Core Structure: A Polarized Mn X-ray Absorption Spectroscopy Study

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

    Lohmiller, Thomas; Shelby, Megan L.; Long, Xi; Yachandra, Vittal K.; Yano, Junko

    2015-05-19

    We studied Ca2+ -depleted and Ca2+ -reconstituted spinach photosystem II using polarized X-ray absorption spectroscopy of oriented PS II preparations to investigate the structural and functional role of the Ca2+ ion in the Mn4O5Ca cluster of the oxygen-evolving complex (OEC). Samples were prepared by low pH/citrate treatment as one-dimensionally ordered membrane layers and poised in the Ca2+ -depleted S1 (S1') and S2 (S2') states, the S2'YZ• state, at which point the catalytic cycle of water oxidation is inhibited, and the Ca2+ -reconstituted S1 state. Polarized Mn K-edge XANES and EXAFS spectra exhibit pronounced dichroism. Polarized EXAFS data of all statesmore » of Ca2+ -depleted PS II investigated show only minor changes in distances and orientations of the Mn-Mn vectors compared to the Ca2+ -containing OEC, which may be attributed to some loss of rigidity of the core structure. Thus, removal of the Ca2+ ion does not lead to fundamental distortion or rearrangement of the tetranuclear Mn cluster, which indicates that the Ca2+ ion in the OEC is not critical for structural maintenance of the cluster, at least in the S1 and S2 states, but fulfills a crucial catalytic function in the mechanism of the water oxidation reaction. On the basis of this structural information, reasons for the inhibitory effect of Ca2+ removal are discussed, attributing to the Ca2+ ion a fundamental role in organizing the surrounding (substrate) water framework and in proton-coupled electron transfer to YZ• (D1-Tyr161).« less

  18. Synthesis, crystal structure, and vibrational spectroscopic and UV-visible studies of Cs{sub 2}MnP{sub 2}O{sub 7}

    SciTech Connect (OSTI)

    Kaoua, Saida; Krimi, Saida; Pechev, Stanislav; Gravereau, Pierre; Chaminade, Jean-Pierre; Couzi, Michel; El Jazouli, Abdelaziz

    2013-02-15

    A new member of the A{sub 2}MP{sub 2}O{sub 7} diphosphate family, Cs{sub 2}MnP{sub 2}O{sub 7}, has been synthesized and structurally characterized. The crystal structure was determined by single crystal X-Ray diffraction. Cs{sub 2}MnP{sub 2}O{sub 7} crystallizes in the orthorhombic system, space group Pnma ( Music-Sharp-Sign 62), with the unit cell parameters a=16.3398(3), b=5.3872(1), c=9.8872(2) A, Z=4 and V=870.33(3) A{sup 3}. The structure parameters were refined to a final R{sub 1}/wR{sub 2}=0.0194/0.0441 for 1650 observed reflections. The 2D framework of Cs{sub 2}MnP{sub 2}O{sub 7} structure consists of P{sub 2}O{sub 7} and MnO{sub 5} units. The corner-shared MnO{sub 5} and P{sub 2}O{sub 7} units are alternately arranged along the b axis to form [(MnO)P{sub 2}O{sub 7}]{sub {infinity}} chains. These chains are interconnected by an oxygen atom to form sheets parallel to the (b, c) plane. The cesium atoms are located between the sheets in 9- and 10-fold coordinated sites. The infrared and Raman vibrational spectra have been investigated. A factor group analysis leads to the determination of internal modes of (P{sub 2}O{sub 7}) groups. UV-visible spectrum consists of weak bands, between 340 and 700 nm, assigned to the forbidden d-d transitions of Mn{sup 2+} ion, and of a strong band around 250 nm, attributed to the O--Mn charge transfer. - Graphical abstract: Structure of Cs{sub 2}MnP{sub 2}O{sub 7}: The 2D structure of Cs{sub 2}MnP{sub 2}O{sub 7} is built from P{sub 2}O{sub 7} diphosphate groups and MnO{sub 5} square pyramids which share corners and form [(MnO)P{sub 2}O{sub 7}]{sub {infinity}} chains along b axis. These chains are interconnected by an oxygen atom to form wavy (MnP{sub 2}O{sub 7}){sup 2-} sheets parallel to the (b, c) plane. The cesium ions are located between these sheets in the inter-layers space, in zigzag positions. Highlights: Black-Right-Pointing-Pointer A new diphosphate, Cs{sub 2}MnP{sub 2}O{sub 7}, has been synthesized and structurally

  19. Magnetic properties of MnSb inclusions formed in GaSb matrix directly during molecular beam epitaxial growth

    SciTech Connect (OSTI)

    Lawniczak-Jablonska, Krystyna; Wolska, Anna; Klepka, Marcin T.; Kret, Slawomir; Kurowska, Boguslawa; Kowalski, Bogdan J.; Twardowski, Andrzej; Wasik, Dariusz; Kwiatkowski, Adam; Sadowski, Janusz

    2011-04-01

    Despite of intensive search for the proper semiconductor base materials for spintronic devices working at room temperature no appropriate material based on ferromagnetic semiconductors has been found so far. We demonstrate that the phase segregated system with MnSb hexagonal inclusions inside the GaSb matrix, formed directly during the molecular beam epitaxial growth reveals the ferromagnetic properties at room temperature and is a good candidate for exploitation in spintronics. Furthermore, the MnSb inclusions with only one crystalline structure were identified in this GaMn:MnSb granular material. The SQUID magnetometry confirmed that this material exhibits ferromagnetic like behavior starting from helium up to room temperature. Moreover, the magnetic anisotropy was found which was present also at room temperature, and it was proved that by choosing a proper substrate it is possible to control the direction of easy axis of inclusions' magnetization moment between in-plane and out-of-plane; the latter is important in view of potential applications in spintronic devices.

  20. Structural, optical, and magnetic properties of Mn and Fe-doped Co{sub 3}O{sub 4} nanoparticles

    SciTech Connect (OSTI)

    Stella, C. Soundararajan, N.; Ramachandran, K.

    2015-08-15

    Mn and Fe-doped Co{sub 3}O{sub 4} nanoparticles were prepared by a simple precipitation method. The synthesized particles were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), UV-Vis absorption spectroscopy, Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, and vibrating sample magnetometer (VSM) techniques. XRD analysis showed the cubic structure of Co{sub 3}O{sub 4}. SEM and TEM images confirmed the formation of interconnected nanoparticles. Mn and Fe-doped Co{sub 3}O{sub 4} showed broad absorption in the visible region compared to undoped sample and the band gap values are red shifted. Five Raman active modes were observed from the Raman spectra. FTIR spectra confirmed the spinel structure of Co{sub 3}O{sub 4} and the doping of Mn and Fe shifts the vibrational modes to lower wave number region. The magnetic measurements confirmed that Fe-doped Co{sub 3}O{sub 4} shows a little ferromagnetic behavior compared to undoped and Mn-doped Co{sub 3}O{sub 4}, which could be related to the uncompensated surface spins and the finite size effects.

  1. Excess Ni-doping induced enhanced room temperature magneto-functionality in Ni-Mn-Sn based shape memory alloy

    SciTech Connect (OSTI)

    Pramanick, S.; Giri, S.; Majumdar, S.; Chatterjee, S.

    2014-09-15

    Present work reports on the observation of large magnetoresistance (??30% at 80 kOe) and magnetocaloric effect (?12?Jkg{sup ?1}K{sup ?1} for 050 kOe) near room temperature (?290?K) on the Ni-excess ferromagnetic shape memory alloy Ni{sub 2.04}Mn{sub 1.4}Sn{sub 0.56}. The sample can be thought of being derived from the parent Ni{sub 2}Mn{sub 1.4}Sn{sub 0.6} alloy, where excess Ni was doped at the expense of Sn. Such Ni doping enhances the martensitic transition temperature and for the Ni{sub 2.04}Mn{sub 1.4}Sn{sub 0.56} it is found to be optimum (288?K). The doped alloy shows enhanced magneto-functional properties as well as reduced saturation magnetization as compared to the undoped counterpart at low temperature. A probable increment of antiferromagnetic correlation between Mn-atoms on Ni substitution can be accounted for the enhanced magneto-functional properties as well as reduction in saturation moment.

  2. Magnetic BiMn-α phase synthesis prediction: First-principles calculation, thermodynamic modeling and nonequilibrium chemical partitioning

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

    Zhou, S. H.; Liu, C.; Yao, Y. X.; Du, Y.; Zhang, L. J.; Wang, C. -Z.; Ho, K. -M.; Kramer, M. J.

    2016-04-29

    BiMn-α is promising permanent magnet. Due to its peritectic formation feature, there is a synthetic challenge to produce single BiMn-α phase. The objective of this study is to assess driving force for crystalline phase pathways under far-from-equilibrium conditions. First-principles calculations with Hubbard U correction are performed to provide a robust description of the thermodynamic behavior. The energetics associated with various degrees of the chemical partitioning are quantified to predict temperature, magnetic field, and time dependence of the phase selection. By assessing the phase transformation under the influence of the chemical partitioning, temperatures, and cooling rate from our calculations, we suggestmore » that it is possible to synthesize the magnetic BiMn-α compound in a congruent manner by rapid solidification. The external magnetic field enhances the stability of the BiMn-α phase. In conclusion, the compositions of the initial compounds from these highly driven liquids can be far from equilibrium.« less

  3. Controlled fabrication and tunable photoluminescence properties of Mn{sup 2+} doped grapheneZnO composite

    SciTech Connect (OSTI)

    Luan, Xinglong; Zhang, Yihe Tong, Wangshu; Shang, Jiwu; An, Qi; Huang, Hongwei

    2014-11-15

    Highlights: GrapheneZnO composites were synthesized by a mixed solvothermal method. ZnO quantum dots are distributed uniformly on the graphene sheets. A possible hypothesis is raised for the influence of graphene oxide on the nucleation of ZnO. Mn{sup 2+} doped grapheneZnO composites were fabricated and the emission spectra can be tuned by doping. - Abstract: GrapheneZnO composites (GZnO) with controlled morphology and photoluminescence property were synthesized by a mixed solvothermal method. Mixed solvent were composed by dimethyl sulfoxide and ethylene glycol. Fourier transform infrared spectroscopy, transmission electron microscopy and photoluminescence spectra were used to characterize GZnO. Graphene as a substrate can help the distribution and the dispersity of ZnO, and a possible model of the interaction between graphene oxide and ZnO particles is proposed. At the same time, graphene also reduce the size of ZnO particles to about 5 nm. Furthermore, Mn{sup 2+} ions dopes GZnO successfully by the mixed solvothermal synthesis and the doping of Mn{sup 2+} makes GZnO shift red from 465 nm to 548 nm and 554 nm in the emission spectrum. The changes of the emission spectrum by the adding of Mn{sup 2+} make GZnO have tunable photoluminescence spectrum which is desirable for practical applications.

  4. CaMn2Sb2: Spin waves on a frustrated antiferromagnetic honeycomb lattice

    SciTech Connect (OSTI)

    McNally, D. E.; Simonson, J. W.; Kistner-Morris, J. J.; Smith, G. J.; Hassinger, J. E.; DeBeer-Schmidt, L.; Kolesnikov, A. I.; Zaliznyak, I.; Aronson, M. C.

    2015-05-22

    We present inelastic neutron scattering measurements of the antiferromagnetic insulator CaMn2Sb2:, which consists of corrugated honeycomb layers of Mn. The dispersion of magnetic excitations has been measured along the H and L directions in reciprocal space, with a maximum excitation energy of ≈ 24 meV. These excitations are well described by spin waves in a Heisenberg model, including first and second neighbor exchange interactions, J1 and J2, in the Mn plane and also an exchange interaction between planes. The determined ratio J2/J1 ≈ 1/6 suggests that CaMn2Sb2: is the first example of a compound that lies very close to the mean field tricritical point, known for the classical Heisenberg model on the honeycomb lattice, where the N´eel phase and two different spiral phases coexist. The magnitude of the determined exchange interactions reveal a mean field ordering temperature ≈ 4 times larger than the reported N´eel temperature TN = 85 K, suggesting significant frustration arising from proximity to the tricritical point.

  5. Unusual magnetic hysteresis and the weakened transition behavior induced by Sn substitution in Mn{sub 3}SbN

    SciTech Connect (OSTI)

    Sun, Ying, E-mail: sunying@buaa.edu.cn [Center for Condensed Matter and Materials Physics, Department of Physics, Beihang University, Beijing 100191 (China); International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science, Tsukuba, Ibaraki 305-0044 (Japan); Guo, Yanfeng; Li, Jun; Wang, Xia [Superconducting Properties Unit, National Institute for Materials Science, Tsukuba, Ibaraki 305-0044 (Japan); Tsujimoto, Yoshihiro [Materials Processing Unit, National Institute for Materials Science, Tsukuba, Ibaraki 305-0047 (Japan); Wang, Cong [Center for Condensed Matter and Materials Physics, Department of Physics, Beihang University, Beijing 100191 (China); Feng, Hai L.; Sathish, Clastin I.; Yamaura, Kazunari, E-mail: yamaura.kazunari@nims.go.jp [Superconducting Properties Unit, National Institute for Materials Science, Tsukuba, Ibaraki 305-0044 (Japan); Graduate School of Chemical Sciences and Engineering, Hokkaido University, Sapporo, Hokkaido 060-0810 (Japan); Matsushita, Yoshitaka [Analysis Station, National Institute for Materials Science, Tsukuba, Ibaraki 305-0047 (Japan)

    2014-01-28

    Substitution of Sb with Sn was achieved in ferrimagnetic antiperovskite Mn{sub 3}SbN. The experimental results indicate that with an increase in Sn concentration, the magnetization continuously decreases and the crystal structure of Mn{sub 3}Sb{sub 1-x}Sn{sub x}N changes from tetragonal to cubic phase at around x of 0.8. In the doping series, step-like anomaly in the isothermal magnetization was found and this behavior was highlighted at x?=?0.4. The anomaly could be attributed to the magnetic frustration, resulting from competition between the multiple spin configurations in the antiperovskite lattice. Meantime, H{sub c} of 18 kOe was observed at x?=?0.3, which is probably the highest among those of manganese antiperovskite materials reported so far. With increasing Sn content, the abrupt change of resistivity and the sharp peak of heat capacity in Mn{sub 3}SbN were gradually weakened. The crystal structure refinements indicate the weakened change at the magnetic transition is close related to the change of c/a ratio variation from tetragonal to cubic with Sn content. The results derived from this study indicate that the behavior of Mn{sub 3}Sb{sub 1-x}Sn{sub x}N could potentially enhance its scientific and technical applications, such as spin torque transfer and hard magnets.

  6. High Curie temperature of Ce-Fe-Si compounds with ThMn12 structure

    SciTech Connect (OSTI)

    Zhou, C; Pinkerton, FE; Herbst, JF

    2015-01-15

    We report the discovery of ternary CeFe(12-x)Si(x)compounds possessing the ThMn12 structure. The samples were prepared by melt spinning followed by annealing. In contrast to other known Ce Fe-based binary and ternary compounds, CeFe12-xSix compounds exhibit exceptionally high Curie temperatures whose values increase with added Si substitution. The highest T. = 583 K in CeFe10Si2 rivals that of the well-established Nd2Fe14B compound. We ascribe the T-c behavior to a combination of Si-induced 3d band structure changes and partial Ce3+ stabilization. (C) 2014 Published by Elsevier Ltd.

  7. Raman spectroscopy of InGaAs/GaAs nanoheterostructures δ-doped with Mn

    SciTech Connect (OSTI)

    Plankina, S. M.; Vikhrova, O. V.; Danilov, Yu. A.; Zvonkov, B. N.; Kalentyeva, I. L.; Nezhdanov, A. V.; Chunin, I. I.; Yunin, P. A.

    2015-01-15

    The results of complex studies of InGaAs/GaAs nanoheterostructures δ-doped with Mn are reported. The structures are grown by metal-organic vapor-phase epitaxy in combination with laser deposition. By confocal Raman spectroscopy, it is shown that the low-temperature δ-doped GaAs cap layers are of higher crystal quality compared to uniformly doped layers. Scattering of light in the coupled phonon-plasmon mode is observed. The appearance of this mode is conditioned by the diffusion of manganese from the δ-layer. The thickness of the cap layer is found to be d{sub c} ≈ 9–20 nm, optimal for attainment of the highest photoluminescence intensity of the quantum well and the highest layer concentration of holes by doping with manganese.

  8. Evidence of martensitic phase transitions in magnetic Ni-Mn-In thin films

    SciTech Connect (OSTI)

    Sokolov, A.; Zhang, Le; Dubenko, I.; Samanta, T.; Ali, N.; Stadler, S.

    2013-02-18

    Ni{sub 50}Mn{sub 35}In{sub 15} Heusler alloy thin films (with thicknesses of about 10 nm) have been grown on single crystal MgO and SrTiO{sub 3} (STO) (100) substrates using a laser-assisted molecular beam epitaxy method. Films of mixed austenitic and martensitic phases and of pure martensitic phase have been detected for those grown on MgO and STO substrates, respectively. Thermomagnetic curves were measured using a SQUID magnetometer and are consistent with those of off-stoichiometric In-based bulk Heusler alloys, including a martensitic transition at T = 315 K for films grown on MgO. The differences in the properties of the films grown on MgO and STO are discussed.

  9. Highly mobile type II twin boundary in Ni-Mn-Ga five-layered martensite

    SciTech Connect (OSTI)

    Sozinov, A.; Lanska, N.; Soroka, A.; Straka, L.

    2011-09-19

    Twin relationships and stress-induced reorientation were studied in Ni{sub 2}Mn{sub 1.14}Ga{sub 0.86} single crystal with five-layered modulated martensite crystal structure. Very low twinning stress of about 0.1 MPa was found for twin boundaries which deviated a few degrees from the (011) crystallographic plane. However, twin boundaries oriented exactly parallel to the (011) plane exhibited considerably higher level of twinning stress, above 1 MPa. X-ray diffraction experiments and calculations based on approximation of the martensite crystal lattice as a tetragonal lattice with a slight monoclinic distortion identified the two different kinds of twin interfaces as type II and type I twin boundaries.

  10. The magnetic ordering in high magnetoresistance Mn-doped ZnO thin films

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

    Venkatesh, S.; Baras, A.; Lee, J. -S.; Roqan, I. S.

    2016-03-24

    Here, we studied the nature of magnetic ordering in Mn-doped ZnO thin films that exhibited ferromagnetism at 300 K and superparamagnetism at 5 K. We directly inter-related the magnetisation and magnetoresistance by invoking the polaronpercolation theory and variable range of hopping conduction below the metal-to-insulator transition. By obtaining a qualitative agreement between these two models, we attribute the ferromagnetism to the s-d exchange-induced spin splitting that was indicated by large positive magnetoresistance (~40 %). Low temperature superparamagnetism was attributed to the localization of carriers and non-interacting polaron clusters. This analysis can assist in understanding the presence or absence of ferromagnetismmore » in doped/un-doped ZnO.« less

  11. High temperature dielectric relaxation anomaly of Y? and Mn? doped barium strontium titanate ceramics

    SciTech Connect (OSTI)

    Yan, Shiguang; Mao, Chaoliang E-mail: xldong@mail.sic.ac.cn; Wang, Genshui; Yao, Chunhua; Cao, Fei; Dong, Xianlin E-mail: xldong@mail.sic.ac.cn

    2014-10-14

    Relaxation like dielectric anomaly is observed in Y? and Mn? doped barium strontium titanate ceramics when the temperature is over 450 K. Apart from the conventional dielectric relaxation analysis method with Debye or modified Debye equations, which is hard to give exact temperature dependence of the relaxation process, dielectric response in the form of complex impedance, assisted with Cole-Cole impedance model corrected equivalent circuits, is adopted to solve this problem and chase the polarization mechanism in this paper. Through this method, an excellent description to temperature dependence of the dielectric relaxation anomaly and its dominated factors are achieved. Further analysis reveals that the exponential decay of the Cole distribution parameter n with temperature is confirmed to be induced by the microscopic lattice distortion due to ions doping and the interaction between the defects. At last, a clear sight to polarization mechanism containing both the intrinsic dipolar polarization and extrinsic distributed oxygen vacancies hopping response under different temperature is obtained.

  12. High spin polarization in CoFeMnGe equiatomic quaternary Heusler alloy

    SciTech Connect (OSTI)

    Bainsla, Lakhan; Suresh, K. G.; Nigam, A. K.; Manivel Raja, M.; Varaprasad, B. S. D. Ch. S.; Takahashi, Y. K.; Hono, K.

    2014-11-28

    We report the structure, magnetic property, and spin polarization of CoFeMnGe equiatomic quaternary Heusler alloy. The alloy was found to crystallize in the cubic Heusler structure (prototype LiMgPdSn) with considerable amount of DO{sub 3} disorder. Thermal analysis result indicated the Curie temperature is about 750 K without any other phase transformation up to melting temperature. The magnetization value was close to that predicted by the Slater-Pauling curve. Current spin polarization of P = 0.70 ± 0.01 was deduced using point contact andreev reflection measurements. The temperature dependence of electrical resistivity has been fitted in the temperature range of 5–300 K in order to check for the half metallic behavior. Considering the high spin polarization and Curie temperature, this material appears to be promising for spintronic applications.

  13. Structural controlled magnetic anisotropy in Heusler L1{sub 0}-MnGa epitaxial thin films

    SciTech Connect (OSTI)

    Wang Kangkang; Lu Erdong; Smith, Arthur R.; Knepper, Jacob W.; Yang Fengyuan

    2011-04-18

    Ferromagnetic L1{sub 0}-MnGa thin films have been epitaxially grown on GaN, sapphire, and MgO substrates using molecular beam epitaxy. Using diffraction techniques, the epitaxial relationships are determined. It is found that the crystalline orientation of the films differ due to the influence of the substrate. By comparing the magnetic anisotropy to the structural properties, a clear correlation could be established indicating that the in-plane and out-of-plane anisotropy is directly determined by the crystal orientation of the film and could be controlled via selection of the substrates. This result could be helpful in tailoring magnetic anisotropy in thin films for spintronic applications.

  14. Electric field-induced magnetic switching in Mn:ZnO film

    SciTech Connect (OSTI)

    Ren, S. X.; Sun, G. W.; Zhao, J.; Dong, J. Y.; Zhao, X.; Chen, W.; Wei, Y.; Ma, Z. C.

    2014-06-09

    A large magnetic modulation, accompanied by stable bipolar resistive switching (RS) behavior, was observed in a Mn:ZnO film by applying a reversible electric field. A significant enhancement of the ferromagnetism of the film, to about five times larger than that in the initial (as-grown) state (IS), was obtained by switching the film into the low resistance state. X-ray photoelectron spectroscopy demonstrated the existence of abundant oxygen vacancies in the IS of the film. We suggest that this electric field-induced magnetic switching effect originates with the migration and redistribution of oxygen vacancies during RS. Our work indicates that electric switching is an effective and simple method to increase the ferromagnetism of diluted magnetic oxide films. This provides a promising direction for research in spintronic devices.

  15. Characterization of LiMn2O4 cathodes by electrochemical strain microscopy

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

    Alikin, D. O.; Ievlev, A. V.; Luchkin, S. Yu.; Turygin, A. P.; Shur, V. Ya.; Kalinin, S. V.; Kholkin, A. L.

    2016-03-15

    Electrochemical strain microscopy (ESM) is a scanning probe microscopy(SPM) method in which the local electrodiffusion is probed via application of AC voltage to the SPM tip and registration of resulting electrochemical strain. In this study, we implemented ESM to measure local strain in bulk LiMn2O4 cathodes of a commercial Li-battery in different states of charge to investigate distribution of Li-ion mobility and concentration. Ramped AC ESM imaging and voltage spectroscopy were used to find the most reliable regime of measurements allowing separating and diminishing different contributions to ESM. This is not a trivial task due to complex geometry of themore » sample and various obstacles resulting in less predictable contributions of different origins into ESM response: electrostatic tip–surface interactions, charge injection, electrostriction, and flexoelectricity. Finally, understanding and control of these contributions is an important step towards quantitative interpretation of ESM data.« less

  16. NaNi sub 3 Mn sub 2 alloy as a tritium storage material

    SciTech Connect (OSTI)

    Ide, T.; Okuno, K.; Konishi, S.; Sakai, F.; Fukui, H.; Enoeda, M.; Naruse, Y.; Anderson, J.L.; Bartlit, J.R.; Los Alamos National Lab., NM )

    1989-01-01

    An all metal apparatus has been constructed and installed in the main cell of the Tritium System Assembly (TSTA) at Los Alamos National Laboratory, as a separate experiment, to handle about 2600 Ci of tritium for study of metal tritides of potential application for storing tritium in fusion fuel processing. The apparatus is similar to that used for protium/deuterium gas but some modifications were made to assure safe handling of tritium. The pressure-composition isotherms for the LaNi{sub 3}Mn{sub 2}-protium (H), deuterium (D) and tritium (T) system were measured to study isotopic effects in the temperature range of 60 {degree}C to 250 {degree}C, the pressure range below 120 kPa. 2 refs., 10 figs.

  17. Strain-induced dimensionality crossover of precursor modulations in Ni{sub 2}MnGa

    SciTech Connect (OSTI)

    Nie, Zhihua E-mail: ydwang@neu.edu.cn; Wang, Yandong E-mail: ydwang@neu.edu.cn; Shang, Shunli; Wang, Yi; Liu, Zi-Kui; Zeng, Qiaoshi; Ren, Yang; Liu, Dongmei; Yang, Wenge

    2015-01-12

    Precursor modulations often occur in functional materials like magnetic shape memory alloys, ferroelectrics, and superconductors. In this letter, we have revealed the underlying mechanism of the precursor modulations in ferromagnetic shape memory alloys Ni{sub 2}MnGa by combining synchrotron-based x-ray diffraction experiments and first-principles phonon calculations. We discovered the precursor modulations along [011] direction can be eliminated with [001] uniaxial loading, while the precursor modulations or premartensite can be totally suppressed by hydrostatic pressure condition. The TA{sub 2} phonon anomaly is sensitive to stress induced lattice strain, and the entire TA{sub 2} branch is stabilized along the directions where precursor modulations are eliminated by external stress. Our discovery bridges precursor modulations and phonon anomalies, and sheds light on the microscopic mechanism of the two-step superelasticity in precursor martensite.

  18. Magnetic-field-induced transformation in FeMnGa alloys

    SciTech Connect (OSTI)

    Zhu, W.; Liu, E. K.; Feng, L.; Tang, X. D.; Chen, J. L.; Wu, G. H.; Liu, H. Y.; Meng, F. B.; Luo, H. Z.

    2009-11-30

    A kind of ferromagnetic shape memory alloy with off-stoichiometric composition of Heusler alloy Fe{sub 2}MnGa has been synthesized. By optimizing composition, the martensitic transformation has been modified to occur at about 163 K accompanying spontaneous magnetization, which enables a magnetic field-induced structural transition from a paramagnetic parent phase to a ferromagnetic martensite with high magnetization of 93.8 emu/g. The material performs a quite large lattice distortion through the transformation, (c-a)/c=33.5%, causing a shape memory strain upto 3.6%. Such large lattice distortions strongly influence the electron structures, and thus some special physical behavior related to the transport and conductive properties is investigated.

  19. The manifestation of spin-phonon coupling in CaMnO{sub 3}

    SciTech Connect (OSTI)

    Goian, V. Kamba, S.; Borodavka, F.; Nuzhnyy, D.; Savinov, M.; Belik, A. A.

    2015-04-28

    Recently predicted presence of spin-phonon coupling in the CaMnO{sub 3} is experimentally confirmed in infrared (IR), Raman and time-domain THz spectra. Most of phonon frequencies seen below 350?cm{sup ?1} exhibit significant shifts on cooling below antiferromagnetic phase transition at T{sub N}???120?K. Moreover, several new modes activate in the IR and Raman spectra on cooling below T{sub N}. Sum of phonon contributions to static permittivity exhibits small but reliable anomaly at T{sub N}. On the other hand, the spin-phonon coupling is not manifested in temperature dependence of radio-frequency permittivity, because intrinsic permittivity is screened by extrinsic contribution from conductivity, which enhances the permittivity to giant values.

  20. Magnetic structure and spin excitations in BaMn2Bi2

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

    Calder, Stuart A.; Saparov, Bayrammurad I; Cao, H. B.; Niedziela, Jennifer L.; Lumsden, Mark D.; Sefat, Athena Safa; Christianson, Andrew D.

    2014-02-19

    We present a single crystal neutron scattering study of BaMn2Bi2, a recently synthesized material with the same ThCr2Si2type structure found in several Fe-based unconventional superconducting materials. We show long range magnetic order, in the form of a G-type antiferromagnetic structure, to exist up to 390 K with an indication of a structural transition at 100 K. Utilizing inelastic neutron scattering we observe a spin-gap of 16 meV, with spin-waves extending up to 55 meV. We find these magnetic excitations are well fit to a J1-J2-Jc Heisenberg model and present values for the exchange interactions. The spin wave spectrum appears tomore » be unchanged by the 100 K structural phase transition.« less

  1. Microstructures and mechanical properties of compositionally complex Co-free FeNiMnCr18 FCC solid solution alloy

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

    Wu, Z.; Bei, H.

    2015-07-01

    Recently, a structurally-simple but compositionally-complex FeNiCoMnCr high entropy alloy was found to have excellent mechanical properties (e.g., high strength and ductility). To understand the potential of using high entropy alloys as structural materials for advanced nuclear reactor and power plants, it is necessary to have a thorough understanding of their structural stability and mechanical properties degradation under neutron irradiation. Furthermore, this requires us to develop a similar model alloy without Co because material with Co will make post-neutron-irradiation testing difficult due to the production of the 60Co radioisotope. In order to achieve this goal, a FCC-structured single-phase alloy with amore » composition of FeNiMnCr18 was successfully developed. This near-equiatomic FeNiMnCr18 alloy has good malleability and its microstructure can be controlled by thermomechanical processing. By rolling and annealing, the as-cast elongated-grained-microstructure is replaced by homogeneous equiaxed grains. The mechanical properties (e.g., strength and ductility) of the FeNiMnCr18 alloy are comparable to those of the equiatomic FeNiCoMnCr high entropy alloy. Both strength and ductility increase with decreasing deformation temperature, with the largest difference occurring between 293 and 77 K. Extensive twin-bands which are bundles of numerous individual twins are observed when it is tensile-fractured at 77 K. No twin bands are detected by EBSD for materials deformed at 293 K and higher. Ultimately the unusual temperature-dependencies of UTS and uniform elongation could be caused by the development of the dense twin substructure, twin-dislocation interactions and the interactions between primary and secondary twinning systems which result in a microstructure refinement and hence cause enhanced strain hardening and postponed necking.« less

  2. Unraveling the voltage fade mechanism in layer Li-Mn-rich electrode: formation of the tetrahedral cations for spinel conversion

    SciTech Connect (OSTI)

    Mohanty, Debasish; Li, Jianlin; Abraham, Daniel P; Huq, Ashfia; Payzant, E Andrew; Wood III, David L; Daniel, Claus

    2014-01-01

    Discovery of high-voltage layered lithium-and manganese-rich (LMR) composite oxide electrode has dramatically enhanced the energy density of current Li-ion energy storage systems. However, practical usage of these materials is currently not viable because of their inability to maintain a consistent voltage profile (voltage fading) during subsequent charge-discharge cycles. This report rationalizes the cause of this voltage fade by providing the evidence of layer to spinel-like (LSL) structural evolution pathways in the host Li1.2Mn0.55Ni0.15Co0.1O2 LMR composite oxide. By employing neutron powder diffraction, and temperature dependent magnetic susceptibility, we show that LSL structural rearrangement in LMR oxide occurs through a tetrahedral cation intermediate via: i) diffusion of lithium atoms from octahedral to tetrahedral sites of the lithium layer [(LiLioct LiLitet] which is followed by the dispersal of the lithium ions from the adjacent octahedral site of the metal layer to the tetrahedral sites of lithium layer [LiTM oct LiLitet]; and ii) migration of Mn from the octahedral sites of the transition metal layer to the permanent octahedral site of lithium layer via tetrahedral site of lithium layer [MnTMoct MnLitet MnLioct)]. The findings opens the door to the potential routes to mitigate this atomic restructuring in the high-voltage LMR composite oxide cathodes by manipulating the composition/structure for practical use in high-energy-density lithium-ion batteries.

  3. Synthesis and characterization of R{sub 2}MnTiO{sub 7} (R = Y and Er) pyrochlores oxides

    SciTech Connect (OSTI)

    Martnez-Coronado, R.; Alonso, J.A.; Fernndez, M.T.

    2013-09-01

    Graphical abstract: - Abstract: New pyrochlore-like phases of composition R{sub 2}MnTiO{sub 7} (R = Er and Y) have been synthesized by a soft-chemistry procedure involving citrates of the different metal ions followed by thermal treatments at moderate temperatures (850 C for 12 h in air). A characterization by X-ray diffraction and neutron powder diffraction (NPD) has been carried out in order to determine the crystal structure features: these phyrochlores are cubic, space group Fd-3m, defining an intrinsically frustrated three-dimensional system. The Rietveld-refinement from NPD data at room temperature evidences an antisite cation disorder (distribution of Mn between A and B positions) that is accompanied by an increment of the oxygen-vacancy concentration due to the reduction of Mn{sup 4+} at the B position to Mn{sup 2+} at the A position. Thermogravimetric analysis (TGA) was useful to evaluate the stability of these oxides in reducing conditions up to 500 C. Magnetic susceptibility measurements indicate a ferromagnetic behavior, due to the random distribution of Mn{sup 4+} ions in the octahedral sublattice. At lower temperatures there is a polarization of the R{sup +3} magnetic moments, which also participate in the magnetic structure. Aiming to evaluate these materials as possible electrodes for solid oxide fuel cells (SOFC) we determined that the thermal expansion coefficients between 100 and 900 C perfectly match with those of the usual electrolytes; however, these pyrochlore oxides display a semiconductor-like behavior with poor conductivity values, e.g. 6 10{sup ?3} cm{sup ?1} at 850 C for Er, which would prevent its use as MIEC (mixed ionic-electronic conductors) oxides in SOFC devices.

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  5. First principles treatment of structural, optical, and thermoelectric properties of Li{sub 7}MnN{sub 4} as electrode for a Li secondary battery

    SciTech Connect (OSTI)

    Khan, Wilayat; Reshak, A.H.

    2015-01-15

    The electronic structure, electronic charge density and linear optical properties of the metallic Li{sub 7}MnN{sub 4} compound, having cubic symmetry, are calculated using the full potential linearized augmented plane wave (FP-LAPW) method. The calculated band structure and density of states using the local density, generalized gradient and EngelVosko approximations, depict the metallic nature of the cubic Li{sub 7}MnN{sub 4} compound. The bands crossing the Fermi level in the calculated band structure are mainly from the Mn-d states with small support of N-p states. In addition, the Mn-d states at the Fermi level enhance the density of states, which is very useful for the electronic transport properties. The valence electronic charge density depicts strong covalent bond between Mn and two N atoms and polar covalent bond between Mn and Li atoms. The frequency dependent linear optical properties like real and imaginary part of the dielectric function, optical conductivity, reflectivity and energy loss function are calculated on the basis of the computed band structure. Both intra-band and inter-band transitions contribute to the calculated optical parameters. Using the BoltzTraP code, the thermoelectric properties like electrical and thermal conductivity, Seebeck coefficient, power coefficient and heat capacity of the Li{sub 7}MnN{sub 4} are also calculated as a function of temperature and studied.

  6. The role of the (111) texture on the exchange bias and interlayer coupling effects observed in sputtered NiFe/IrMn/Co trilayers

    SciTech Connect (OSTI)

    Castro, I. L.; Nascimento, V. P.; Passamani, E. C.; Takeuchi, A. Y.; Larica, C.; Tafur, M.; Pelegrini, F.

    2013-05-28

    Magnetic properties of sputtered NiFe/IrMn/Co trilayers grown on different seed layers (Cu or Ta) deposited on Si (100) substrates were investigated by magnetometry and ferromagnetic resonance measurements. Exchange bias effect and magnetic spring behavior have been studied by changing the IrMn thickness. As shown by X-ray diffraction, Ta and Cu seed layers provoke different degrees of (111) fcc-texture that directly affect the exchange bias and indirectly modify the exchange spring coupling behavior. Increasing the IrMn thickness, it was observed that the coupling angle between the Co and NiFe ferromagnetic layers increases for the Cu seed system, but it reduces for the Ta case. The results were explained considering (i) different anisotropies of the Co and IrMn layers induced by the different degree of the (111) texture and (ii) the distinct exchange bias set at the NiFe/IrMn and IrMn/Co interfaces in both systems. The NiFe and Co interlayer coupling angle is strongly correlated with both exchange bias and exchange magnetic spring phenomena. It was also shown that the highest exchange bias field occurs when an unstressed L1{sub 2} IrMn structure is stabilized.

  7. Electrical conductivity anomaly and X-ray photoelectron spectroscopy investigation of YCr{sub 1?x}Mn{sub x}O{sub 3} negative temperature coefficient ceramics

    SciTech Connect (OSTI)

    Zhang, Bo; University of Chinese Academy of Sciences, Beijing 100049 ; Zhao, Qing; Chang, Aimin E-mail: wuy@alfred.edu; Li, Yiyu; Liu, Yin; Wu, Yiquan E-mail: wuy@alfred.edu

    2014-03-10

    Electrical conductivity anomaly of perovskite-type YCr{sub 1?x}Mn{sub x}O{sub 3} negative temperature coefficient (NTC) ceramics produced by spark plasma sintering (SPS) has been investigated by using defect chemistry theory combination with X-ray photoelectron spectroscopy (XPS) analysis. From the results of the ln?-1/T curves and the XPS analysis, it can be considered that YCr{sub 1?x}Mn{sub x}O{sub 3} ceramics exhibit the hopping conductivity. The major carriers in YCrO{sub 3} are holes, which are compensated by the oxygen vacancies produced due to the introduction of Mn ions. The Mn{sup 4+} ion contents increase monotonically in the range of 0.2???x???0.5. The resistivity increases at first and then decreases with increasing Mn contents, which has the same varying tendency with activation energy. The electrical conductivity anomaly appearing in these ceramics may be due to the variation of Cr{sup 4+} and Mn{sup 4+} ions concentration as Mn content changes.

  8. Cd{sub 1−x}Mn{sub x}Te ultrasmall quantum dots growth in a silicate glass matrix by the fusion method

    SciTech Connect (OSTI)

    Dantas, Noelio Oliveira; Lima Fernandes, Guilherme de; Almeida Silva, Anielle Christine; Baffa, Oswaldo; Gómez, Jorge Antônio

    2014-09-29

    In this study, we synthesized Cd{sub 1−x}Mn{sub x}Te ultrasmall quantum dots (USQDs) in SiO{sub 2}-Na{sub 2}CO{sub 3}-Al{sub 2}O{sub 3}-B{sub 2}O{sub 3} glass system using the fusion method. Growth of these Cd{sub 1−x}Mn{sub x}Te USQDs was confirmed by optical absorption, atomic force microscopy (AFM), magnetic force microscopy (MFM), scanning transmission electron microscopy (TEM), and electron paramagnetic resonance (EPR) measurements. The blueshift of absorption transition with increasing manganese concentration gives evidence of incorporation of manganese ions (Mn{sup 2+}) in CdTe USQDs. AFM, TEM, and MFM confirmed, respectively, the formation of high quality Cd{sub 1−x}Mn{sub x}Te USQDs with uniformly distributed size and magnetic phases. Furthermore, EPR spectra showed six lines associated to the S = 5/2 spin half-filled d-state, characteristic of Mn{sup 2+}, and confirmed that Mn{sup 2+} are located in the sites core and surface of the CdTe USQD. Therefore, synthesis of high quality Cd{sub 1−x}Mn{sub x}Te USQDs may allow the control of optical and magnetic properties.

  9. Effect of CoFe insertion in Co{sub 2}MnSi/CoFe/n-GaAs junctions on spin injection properties

    SciTech Connect (OSTI)

    Ebina, Yuya; Akiho, Takafumi; Liu, Hong-xi; Yamamoto, Masafumi; Uemura, Tetsuya

    2014-04-28

    The CoFe thickness (t{sub CoFe}) dependence of spin injection efficiency was investigated for Co{sub 2}MnSi/CoFe/n-GaAs junctions. The ?V{sub NL}/I value, which is a measure of spin injection efficiency, strongly depended on t{sub CoFe}, where ?V{sub NL} is the amplitude of a nonlocal spin-valve signal, and I is an injection current. Importantly, the maximum value of ?V{sub NL}/I for a Co{sub 2}MnSi/CoFe/n-GaAs junction was one order of magnitude higher than that for a CoFe/n-GaAs junction, indicating that a Co{sub 2}MnSi electrode works as a highly polarized spin source. No clear spin signal, on the other hand, was observed for a Co{sub 2}MnSi/n-GaAs junction due to diffusion of Mn atoms into the GaAs channel. Secondary ion mass spectrometry analysis indicated that the CoFe insertion effectively suppressed the diffusion of Mn into GaAs, resulting in improved spin injection properties compared with those for a Co{sub 2}MnSi/n-GaAs junction.

  10. The effect of Ca-substitution in La-site on the magnetic properties of La{sub 2}CoMnO{sub 6}

    SciTech Connect (OSTI)

    Li, Qiu-hang; Li, Na; Hu, Jian-zhong; Han, Qi; Ma, Qing-shan; Ge, Lei; Xiao, Biao; Xu, Ming-xiang

    2014-07-21

    Double perovskite La{sub 2-x}Ca{sub x}CoMnO{sub 6} (x?=?0, 0.1, 0.2, 0.5) ceramics samples were synthesized by the standard solid-state reaction method. The crystal structures have been confirmed to be monoclinic perovskite structure with space group of P2{sub 1}/n at room temperature by the powder x-ray diffraction (Cu-K?). The grains of the samples are relatively dense and distribute in random directions from the scanning electron microscope patterns. Holes are doped into La{sub 2}CoMnO{sub 6} with the substitution of the Ca{sup 2+} ions in La-site, and further lead to the valences of Mn ions and Co ions transforming from Mn{sup 4+} and Co{sup 2+} to Mn{sup 3+} and Co{sup 3+}, respectively. Ferromagnetic coupling of Mn{sup 4+}-O{sup 2}-Co{sup 2+} and antiferromagnetic coupling of Mn{sup 3+}-O{sup 2}-Co{sup 3+} are coexistent in La{sub 2-x}Ca{sub x}CoMnO{sub 6} system, which correspond to two transitions existed in field-cooling magnetization versus temperature curves. Curie temperature of La{sub 2-x}Ca{sub x}CoMnO{sub 6} system decreases with the increasing of Ca-substitution amount. The coexistence of different magnetic phases leads to the exchange bias effect.

  11. Effect of L1{sub 2} ordering in antiferromagnetic Ir-Mn epitaxial layer on exchange bias of FePd films

    SciTech Connect (OSTI)

    Chang, Y. C.; Duh, J. G. E-mail: lin.yg@nsrrc.org.tw; Hsiao, S. N. E-mail: lin.yg@nsrrc.org.tw; Liu, S. H.; Su, S. H.; Chiu, K. F.; Hsieh, W. C.; Chen, S. K.; Lin, Y. G. E-mail: lin.yg@nsrrc.org.tw; Lee, H. Y.; Sung, C. K.

    2015-05-07

    Two series of samples of single-layer IrMn and IrMn/FePd bilayer films, deposited on a single-crystal MgO substrate at different IrMn deposition temperatures (T{sub s} = 300–700 °C), were investigated using magnetron sputtering. L1{sub 2} ordering was revealed for the 30 nm-thick IrMn epitaxial (001) films with T{sub s} ≥ 400 °C, determined by synchrotron radiation x-ray diffractometry (XRD). XRD results also provide evidence of the epitaxial growth of the IrMn films on MgO substrate. Increasing T{sub s} from 400 to 700 °C monotonically increases the ordering parameter of L1{sub 2} phases from 0.17 to 0.81. An in-plane exchange bias field (H{sub eb}) of 22 Oe is obtained in a 10 nm-thick FePd film that is deposited on the disordered IrMn films. As the L1{sub 2} ordering of the IrMn layers increases, the H{sub eb} gradually decreases to 0 Oe, meaning that the exchange bias behavior vanishes. The increased surface roughness, revealed by atomic force microscopy, of the epitaxial IrMn layers with increasing T{sub s} cannot be the main cause of the decrease in H{sub eb} due to the compensated surface spins regardless of the disordered and ordered (001) IrMn layers. The change of antiferromagnetic structure from the A1 to the L1{sub 2} phase was correlated with the evolution of H{sub eb}.

  12. Synthesis of murdochite-type Ni{sub 6}MnO{sub 8} with variable specific surface areas and the application in methane oxidation

    SciTech Connect (OSTI)

    Taguchi, Hideki; Tahara, Shohei; Okumura, Mikoto; Hirota, Ken

    2014-07-01

    To synthesize a murdochite-type Ni{sub 6}MnO{sub 8} with variable specific surface areas, an oxalate precursor was calcined at 350500 C in flowing argon, and the calcined sample was heated to 600 C in air. The lattice constant of the Ni{sub 6}MnO{sub 8} did not depend on the calcination temperature of the precursor, while the specific surface area decreased from 8.4 m{sup 2}/g to 2.6 m{sup 2}/g when increasing the calcination temperature of the precursor. The methane (CH{sub 4}) oxidation data indicated that the temperature corresponding to the 50% conversion (T{sub 50%}) of Ni{sub 6}MnO{sub 8} calcined at 350 C or 400 C was lower than that of all other Ni{sub 6}MnO{sub 8} specimens. However, the intrinsic conversion of Ni{sub 6}MnO{sub 8} calcined at 350 C, which is defined as conversion per specific surface area, was half of that of all other Ni{sub 6}MnO{sub 8} specimens. The degree of crystallinity and catalytic performance of the Ni{sub 6}MnO{sub 8} calcined at 400 C were high. - Graphical abstract: The conversion of CH{sub 4} into CO{sub 2} and H{sub 2}O on Ni{sub 6}MnO{sub 8}, which was heated at 600 C in air after the calcination of the precursor at 350 C, 400 C, 450 C, or 500 C in flowing argon, was measured. Since the specific surface area was strongly affected by the calcination temperature of the precursor, intrinsic conversion (IC) was defined as conversion per the specific surface area. For comparison, the IC value on Ni{sub 6}MnO{sub 8} synthesized by the direct calcination of the precursor at 600 C in air is plotted. - Highlights: The oxalate precursor was calcined at 350500 C in flowing argon. Murdochite-type Ni{sub 6}MnO{sub 8} was obtained by heating the calcined sample in air. The specific surface area of Ni{sub 6}MnO{sub 8} varied with the calcination temperature. The degree of crystallinity and catalysis of Ni{sub 6}MnO{sub 8} calcined at 400 C were high.

  13. Strong room-temperature ferromagnetism of high-quality lightly Mn-doped ZnO grown by molecular beam epitaxy

    SciTech Connect (OSTI)

    Zuo Zheng; Zhou Huimei; Olmedo, Mario J.; Kong Jieying; Liu Jianlin; Beyermann, Ward P.; Zheng Jianguo; Xin Yan

    2012-09-01

    Strong room-temperature ferromagnetism is demonstrated in single crystalline Mn-doped ZnO grown by molecular beam epitaxy. With a low Mn concentration of 2 Multiplication-Sign 10{sup 19} cm{sup -3}, Mn-doped ZnO films exhibited room-temperature ferromagnetism with a coercivity field larger than 200 Oe, a large saturation moment of 6 {mu}{sub B}/ion, and a large residue moment that is {approx}70% of the saturation magnetization. Isolated ions with long range carrier mediated spin-spin coupling may be responsible for the intrinsic ferromagnetism.

  14. In-plane tunneling anisotropic magnetoresistance in (Ga,Mn)As/GaAs Esaki diodes in the regime of the excess current

    SciTech Connect (OSTI)

    Shiogai, J.; Ciorga, M. Utz, M.; Schuh, D.; Bougeard, D.; Weiss, D.; Kohda, M.; Nitta, J.; Nojima, T.

    2015-06-29

    We investigate the angular dependence of the tunneling anisotropic magnetoresistance in (Ga,Mn)As/n-GaAs spin Esaki diodes in the regime where the tunneling process is dominated by the excess current through midgap states in (Ga,Mn)As. We compare it to similar measurements performed in the regime of band-to-band tunneling. Whereas the latter show biaxial symmetry typical for magnetic anisotropy observed in (Ga,Mn)As samples, the former is dominated by uniaxial anisotropy along the 〈110〉 axes.

  15. Atomic moments in Mn2CoAl thin films analyzed by X-ray magnetic circular dichroism

    SciTech Connect (OSTI)

    Jamer, M.; Sterbinsky, G.; Assaf, B.; Arena, D.; Heiman, D.

    2014-12-05

    Spin gapless semiconductors are known to be strongly affected by structural disorder when grown epitaxially as thin films. The magnetic properties of Mn2CoAl thin films grown on GaAs (001) substrates are investigated here as a function of annealing. This study investigates the atomic-specific magnetic moments of Mn and Co atoms measured through X-ray magnetic circular dichroism as a function of annealing and the consequent structural ordering. The results indicate that the structural distortion mainly affects the Mn atoms as seen by the reduction of the magnetic moment from its predicted value. (auth)

  16. Atomic moments in Mn2CoAl thin films analyzed by X-ray magnetic circular dichroism

    SciTech Connect (OSTI)

    Jamer, M. E.; Assaf, B. A.; Sterbinsky, G. E.; Arena, D. A.; Heiman, D.

    2014-12-05

    Spin gapless semiconductors are known to be strongly affected by structural disorder when grown epitaxially as thin films. The magnetic properties of Mn2CoAl thin films grown on GaAs (001) substrates are investigated here as a function of annealing. This study investigates the atomic-specific magnetic moments of Mn and Co atoms measured through X-ray magnetic circular dichroism as a function of annealing and the consequent structural ordering. Results indicate that the structural distortion mainly affects the Mn atoms as seen by the reduction of the magnetic moment from its predicted value.

  17. Magneto-transport in LaTi{sub 1−x}Mn{sub x}O{sub 3}/SrTiO{sub 3} oxide heterostructures

    SciTech Connect (OSTI)

    Kumar, Pramod Dogra, Anjana Budhani, R. C.

    2014-04-24

    We report the growth of ultrathin film of Mn doped LaTiO{sub 3} on TiO{sub 2} terminated SrTiO{sub 3} (001) substrate by pulsed laser deposition (PLD) and their electrical transport characteristics including magnetoresistance (MR). Though the replacement of Mn in LaTiO{sub 3} at the Ti site in dilute limit does not affect the metallic behaviour of films but variation in resistance is observed. Normalised resistance behaviour is explained on the basis of variation in charge carriers and increased interaction between Mn atoms in the system under investigation.

  18. Immunosuppressive effect of the anti-IL-2-receptor monoclonal antibody, AMT-13, on organ-cultured fetal pancreas allograft survival

    SciTech Connect (OSTI)

    Burkhardt, K.; Loughnan, M.S.; Diamantstein, T.; Mandel, T.E.

    1988-11-01

    Recently, prolongation of cardiac allograft survival in mice was reported using a rat anti-IL-2R mAb (AMT-13). However, its immunosuppressive action in vivo, alone and in combination with other immunosuppressants, and its effect on other organ transplants has not been extensively studied. We grafted cultured fetal pancreas from CBA (H-2k) donors to Balb/c (H-2d) mice. Recipients were treated with 10 consecutive daily injections each of 20 micrograms AMT-13 only, or with an additional mild immunosuppression of 350 rads irradiation. Control groups received rat immunoglobulin or 350 rads irradiation. Graft survival and the phenotype of infiltrating cells were assessed histologically and immunocytochemically on days 12, 17, and 21, and soluble IL-2R levels were measured in the serum with a quantitative ELISA in all recipients. Two of five grafts in the AMT-13-treated group had islets on day 12 posttransplantation despite lymphocytic infiltration in all grafts, while at this time all grafts of rat Ig treated control mice were completely rejected with only scar tissue and a few lymphocytes remaining. Additional immunosuppression with 350 rads irradiation had a marked additive effect with AMT-13. Soluble IL-2R levels in the serum of untreated recipients were not elevated compared with normal serum levels, but recipients injected with AMT-13 had multifold increased soluble IL-2R levels. The percentage of IL-2R+ cells in the grafts of AMT-13-treated animals was either normal (less than 5%) or increased (20%) in the additionally irradiated mice, providing strong evidence that the immunosuppressive effect of AMT-13 is not due to a depletion of activated IL-2R+ lymphocytes.

  19. Sign Reversal of the MN-O Bond Compressibility in La{sub 1.2}Sr{sub 1.8}Mn{sub 2}O{sub 7} Below T{sub C}: Exchange Striction in the Ferromagnetic State

    DOE R&D Accomplishments [OSTI]

    Argyriou, D. N.; Mitchell, J. F.; Chmaissem, O.; Short, S.; Jorgensen, J. D.; Goodenough, J. B.

    1997-03-01

    The crystal structure of the layered perovskite La{sub 1.2}Sr{sub 1.8}Mn{sub 2}O{sub 7} has been studied under hydrostatic pressure up to {approximately} 6 kbar, in the paramagnetic and ferromagnetic states, with neutron powder diffraction. The compressibility of the Mn-O apical bonds in the double layer of MnO{sub 6} octahedra changes sign from the paramagnetic insulator (PI) to the ferromagnetic metal (FM) state; in the Fm state the Mn-O-Mn linkage between MnO{sub 2} planes expands under applied pressure, whereas they contract in the PI state. This counterintuative behavior is interpreted in terms of exchange striction, which reflect the competition between super- and double-exchange. An increase of the Mn-moment with applied pressure in the FM state is consistent with a positive dT{sub C}/dP, as well as a cant angle {theta}{sub 0} between the magnetizations of neighboring MnO{sub 2} sheets that decreases with pressure.

  20. Thermal spray removal of lead-based paint from the viaduct bridge at Rock Island Arsenal, IL. Final report

    SciTech Connect (OSTI)

    Boy, J.H.; Weber, R.A.; Kumar, A.

    1998-06-01

    This report documents a field demonstration at the Rock Island Arsenal, IL, that validated the thermal spray vitrification (TSV) process as a safe and effective technique for removing lead-based paint from a steel bridge. Specially formulated glass was applied in a molten state to painted steel using a conventional thermal spray application system. The molten glass reacts with the paint, and encapsulates the lead. The cooled glass readily cracks and falls off, removing the paint. After onsite remelting of the glass waste to complete the encapsulation process, the final waste product is chemically inert and may be disposed of in a regular landfill. The Illinois Environmental Protection Agency, Division of Air Pollution Control determined that the glass remelt process could be considered a paint-removal operation for which no air quality permit was required.

  1. Magnetic Transitions in the Spin-5/2 Frustrated Magnet BiMn2PO6 and Strong Lattice Softening in BiMn2PO6 and BiZn2PO6 Below 200 K

    SciTech Connect (OSTI)

    Nath, R; Ranjith, K M; Roy, B; Johnston, D C; Furukawa, Y; Tsirlin, A A

    2014-07-01

    The crystallographic, magnetic, and thermal properties of polycrystalline BiMn2PO6 and its nonmagnetic analog BiZn2PO6 are investigated by x-ray diffraction, magnetization M, magnetic susceptibility ?, heat capacity Cp, and P31 nuclear magnetic resonance (NMR) measurements versus applied magnetic field H and temperature T as well as by density-functional band theory and molecular-field calculations. Both compounds show a strong monotonic lattice softening on cooling, where the Debye temperature decreases by a factor of two from ?D?650 K at T=300 K to ?D?300 K at T=2 K. The ?(T) data for BiMn2PO6 above 150 K follow a Curie-Weiss law with a Curie constant consistent with a Mn+2 spin S=5/2 with g factor g=2 and an antiferromagnetic (AFM) Weiss temperature ?CW??78 K. The ? data indicate long-range AFM ordering below TN?30 K, confirmed by a sharp ?-shaped peak in Cp(T) at 28.8 K. The magnetic entropy at 100 K extracted from the Cp(T) data is consistent with spin S=5/2 for the Mn+2 cations. The band-theory calculations indicate that BiMn2PO6 is an AFM compound with dominant interactions J1/kB?6.7 K and J3/kB?5.6 K along the legs and rungs of a Mn two-leg spin-ladder, respectively. However, sizable and partially frustrating interladder couplings lead to an anisotropic three-dimensional magnetic behavior with long-range AFM ordering at TN?30 K observed in the ?, Cp, and NMR measurements. A second magnetic transition at ?10 K is observed from the ? and NMR measurements but is not evident in the Cp data. The Cp data at low T suggest a significant contribution from AFM spin waves moving in three dimensions and the absence of a spin-wave gap. A detailed analysis of the NMR spectra indicates commensurate magnetic order between 10 and 30 K, while below 10 K additional features appear that may arise from an incommensurate modulation and/or spin canting. The commensurate order is consistent with microscopic density functional calculations that yield a collinear Nel-type AFM spin

  2. Enhance D. C. resistivity of Ba{sub 0.7}Sr{sub 0.3}TiO{sub 3} ceramic by acceptor (Mn) doping

    SciTech Connect (OSTI)

    Sharma, Hakikat Arya, G. S.; Pramar, Kusum; Negi, N. S.

    2015-05-15

    In the present work, we prepared Ba{sub 0.7}Sr{sub 0.3}TiO{sub 3} and Mn (2 and 3 at % on Ti site) doped Ba{sub 0.7}Sr{sub 0.3}TiO{sub 3} ceramic by sol- gel method. The samples were characterized by X-ray diffraction (XRD). The XRD patterns reveled that Mn ions did not change the perovskite structure of BST (70/30). The dielectric measurements proved that dielectric constant decreased with Mn doping. The dc resistivity was studied by using I-V measurements. The dc resistivity of the BST increased with Mn doping, which suppressed the leakage current.

  3. Properties of molecular beam epitaxy grown Eu{sub x}(transition metal){sub y} films (transition metals: Mn, Cr)

    SciTech Connect (OSTI)

    Balin, K.; Nowak, A.; Gibaud, A.; Szade, J.; Celinski, Z.

    2011-04-01

    The electronic and crystallographic structures, as well as the magnetic properties, of Eu{sub x}(transition metal){sub y} (transition metals: Mn, Cr) thin films grown by molecular beam epitaxy were studied. Relative changes of the Eu/Mn and Eu/Cr ratios derived from the XPS lines, as well as x-ray reflectivity, indicate mixing of the Eu/Mn and Eu/Cr layers. Valency transitions from Eu{sup 2+} to Eu{sup 3+} were observed in both systems for most studied stoichiometries. A transition to a magnetically ordered phase was observed at 15 K, 40 K, and 62 K for selected films in the Eu-Mn system, and at 50 K for the film with a Eu/Cr ratio of 0.5.

  4. Bicolor Mn-doped CuInS{sub 2}/ZnS core/shell nanocrystals for white light-emitting diode with high color rendering index

    SciTech Connect (OSTI)

    Huang, Bo; Dai, Qian; Zhang, Huichao; Liao, Chen; Cui, Yiping; Zhang, Jiayu; Zhuo, Ningze; Jiang, Qingsong; Shi, Fenghua; Wang, Haibo

    2014-09-07

    We synthesized bicolor Mn-doped CuInS{sub 2} (CIS)/ZnS core/shell nanocrystals (NCs), in which Mn{sup 2+} ions and the CIS core were separated with a ZnS layer, and both Mn{sup 2+} ions and CIS cores could emit simultaneously. Transmission electron microscopy and powder X-ray diffraction measurements indicated the epitaxial growth of ZnS shell on the CuInS{sub 2} core, and electron paramagnetic resonance spectrum indicated that Mn{sup 2+} ions were on the lattice points of ZnS shell. By integrating these bicolor NCs with commercial InGaN-based blue-emitting diodes, tricolor white light-emitting diodes with color rendering index of 83 were obtained.

  5. The effects of high magnetic field on the morphology and microwave electromagnetic properties of MnO{sub 2} powder

    SciTech Connect (OSTI)

    Jia Zhang [Department of Materials Processing Engineering, School of Materials Science and Engineering, Dalian University of Technology, Linggong Road 2, Ganjingzi District, Dalian 116085, Liaoning Province (China); Duan Yuping, E-mail: duanyp@dlut.edu.c [Department of Materials Processing Engineering, School of Materials Science and Engineering, Dalian University of Technology, Linggong Road 2, Ganjingzi District, Dalian 116085, Liaoning Province (China); Li Shuqing, E-mail: lsq6668@126.co [Beijing Aeronautical Manufacturing Technology Research Institute, 1 Jun Zhuang east Road, Chaoyang District, Beijing 100024 (China); Li Xiaogang, E-mail: lixiaogang99@263.ne [School of Materials Science and Engineering, University of Science and Technology Beijing, 30 Xueyuan Road, Haidian District, Beijing 100083 (China); Liu Shunhua [Department of Materials Processing Engineering, School of Materials Science and Engineering, Dalian University of Technology, Linggong Road 2, Ganjingzi District, Dalian 116085, Liaoning Province (China)

    2010-07-15

    MnO{sub 2} with a sea urchin-like ball chain shape was first synthesized in a high magnetic field via a simple chemical process, and a mechanism for the formation of this grain shape was discussed. The as-synthesized samples were characterized by XRD, SEM, TEM, and vector network analysis. The dielectric constant and the loss tangent clearly decreased under a magnetic field. The magnetic loss tangent and the imaginary part of the magnetic permeability increased substantially. Furthermore, the theoretically calculated values of reflection loss showed that the absorption peaks shifted to a higher frequency with increases in the magnetic field strength. - Graphical abstract: MnO{sub 2} with a sea urchin-like ball chain shape is first synthesized in a high magnetic field via a simple hydrothermal route.

  6. Epitaxial Mn{sub 2.5}Ga thin films with giant perpendicular magnetic anisotropy for spintronic devices

    SciTech Connect (OSTI)

    Wu Feng; Mizukami, Shigemi; Watanabe, Daisuke; Miyazaki, Terunobu; Naganuma, Hiroshi; Oogane, Mikihiko; Ando, Yasuo

    2009-03-23

    We report on epitaxial growth and magnetic properties of Mn{sub 2.5}Ga thin films, which were deposited on Cr/MgO single crystal substrates by magnetron sputtering. X-ray diffraction results revealed the epitaxial relationships as Mn{sub 2.5}Ga(001)[100] parallel Cr(001)[110] parallel MgO(001)[100]. The presence of (002) and (011) superlattice peaks indicates that the films were crystallized into DO{sub 22} ordered structures. The perpendicular magnetic anisotropy (PMA) properties were found to be related to the extent of DO{sub 22} chemical ordering. A giant PMA (K{sub u}{sup eff}=1.2x10{sup 7} erg/cm{sup 3}) and low saturation magnetization (M{sub s}=250 emu/cm{sup 3}) can be obtained for the film with highest chemical ordering parameter (S=0.8)

  7. Conditions for spin-gapless semiconducting behavior in Mn{sub 2}CoAl inverse Heusler compound

    SciTech Connect (OSTI)

    Galanakis, I.; zdo?an, K.; ?a??o?lu, E.; Blgel, S.

    2014-03-07

    Employing ab initio electronic structure calculations, we investigate the conditions for spin-gapless semiconducting (SGS) behavior in the inverse Mn{sub 2}CoAl Heusler compound. We show that tetragonalization of the lattice, which can occur during films growth, keeps the SGS character of the perfect cubic compound. On the contrary, atomic swaps even between sites with different local symmetry destroy the SGS character giving rise to a half-metallic state. Furthermore, the occurrence of Co-surplus leads also to half-metallicity. Thus, we propose that in order to achieve SGS behavior during the growth of Mn{sub 2}CoAl (and similar SGS Heusler compounds) thin films, one should minimize the occurrence of defects, while small deformations of the lattice, due to the lattice mismatch with the substrate, do not play a crucial role.

  8. Alternating magnetic anisotropy of Li2(Li1–xTx)N (T = Mn, Fe, Co, and Ni)

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

    Jesche, A.; Ke, L.; Jacobs, J. L.; Harmon, B.; Houk, R. S.; Canfield, P. C.

    2015-05-11

    Substantial amounts of the transition metals Mn, Fe, Co, and Ni can be substituted for Li in single crystalline Li2(Li1–xTx)N. Isothermal and temperature-dependent magnetization measurements reveal local magnetic moments with magnitudes significantly exceeding the spin-only value. The additional contributions stem from unquenched orbital moments that lead to rare-earth-like behavior of the magnetic properties. Accordingly, extremely large magnetic anisotropies have been found. Most notably, the magnetic anisotropy alternates as easy plane→easy axis→easy plane→easy axis when progressing from T = Mn → Fe → Co → Ni. This behavior can be understood based on a perturbation approach in an analytical, single-ion model.more » As a result, the calculated magnetic anisotropies show surprisingly good agreement with the experiment and capture the basic features observed for the different transition metals.« less

  9. Intrinsic quantum anomalous Hall effect in the kagome lattice Cs2LiMn3F12

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

    Xu, Gang; Lian, Biao; Zhang, Shou -Cheng

    2015-10-27

    In a kagome lattice, the time reversal symmetry can be broken by a staggered magnetic flux emerging from ferromagnetic ordering and intrinsic spin-orbit coupling, leading to several well-separated nontrivial Chern bands and intrinsic quantum anomalous Hall effect. Based on this idea and ab initio calculations, we propose the realization of the intrinsic quantum anomalous Hall effect in the single layer Cs2Mn3F12 kagome lattice and on the (001) surface of a Cs2LiMn3F12 single crystal by modifying the carrier coverage on it, where the band gap is around 20 meV. Furthermore, a simplified tight binding model based on the in-plane ddσ antibondingmore » states is constructed to understand the topological band structures of the system.« less

  10. Alternating magnetic anisotropy of Li 2 ( Li 1 - x T x ) N ( T = Mn , Fe , Co , and Ni )

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

    Jesche, A.; Ke, L.; Jacobs, J. L.; Harmon, B.; Houk, R. S.; Canfield, P. C.

    2015-05-01

    Substantial amounts of the transition metals Mn, Fe, Co, and Ni can be substituted for Li in single crystalline Li?(Li1-xTx)N. Isothermal and temperature-dependent magnetization measurements reveal local magnetic moments with magnitudes significantly exceeding the spin-only value. The additional contributions stem from unquenched orbital moments that lead to rare-earth-like behavior of the magnetic properties. Accordingly, extremely large magnetic anisotropies have been found. Most notably, the magnetic anisotropy alternates as easy plane?easy axis?easy plane?easy axis when progressing from T = Mn ? Fe ? Co ? Ni. This behavior can be understood based on a perturbation approach in an analytical, single-ion model.moreThe calculated magnetic anisotropies show surprisingly good agreement with the experiment and capture the basic features observed for the different transition metals.less

  11. Annealing effects on the structural and magnetic properties of off-stoichiometric Fe-Mn-Ga ferromagnetic shape memory alloys

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

    Chen, Yan; Bei, Hongbin; Dela Cruz, Clarina R; Wang, Yandong; An, Ke

    2016-05-07

    Annealing plays an important role in modifying structures and properties of ferromagnetic shape memory alloys (FSMAs). The annealing effect on the structures and magnetic properties of off-stoichiometric Fe45Mn26Ga29 FSMA has been investigated at different elevated temperatures. Rietveld refinements of neutron diffraction patterns display that the formation of the γ phase in Fe45Mn26Ga29 annealed at 1073 K increases the martensitic transformation temperature and reduces the thermal hysteresis in comparison to the homogenized sample. The phase segregation of a Fe-rich cubic phase and a Ga-rich cubic phase occurs at the annealing temperature of 773 K. The atomic occupancies of the alloys aremore » determined thanks to the neutron's capability of differentiating transition metals. The annealing effects at different temperatures introduce a different magnetic characteristic that is associated with distinctive structural changes in the crystal.« less

  12. Metallic transport and large anomalous Hall effect at room temperature in ferrimagnetic Mn{sub 4}N epitaxial thin film

    SciTech Connect (OSTI)

    Shen, Xi; Shigematsu, Kei; Chikamatsu, Akira Fukumura, Tomoteru; Hirose, Yasushi; Hasegawa, Tetsuya

    2014-08-18

    We report the electrical transport properties of ferrimagnetic Mn{sub 4}N (001) epitaxial thin films grown by pulsed laser deposition on MgO (001) substrates. The Mn{sub 4}N thin films were tetragonally distorted with a ratio of out-of-plane to in-plane lattice constants of 0.987 and showed perpendicular magnetic anisotropy with an effective magnetic anisotropy constant of 0.16 MJ/m{sup 3}, which is comparable with that of a recently reported molecular-beam-epitaxy-grown film. The thin films exhibited metallic transport with a room temperature resistivity of 125 μΩ cm in addition to a large anomalous Hall effect with a Hall angle tangent of 0.023.

  13. Giant spontaneous Hall effect in zero-moment Mn{sub 2}Ru{sub x}Ga

    SciTech Connect (OSTI)

    Thiyagarajah, Naganivetha; Lau, Yong-Chang; Betto, Davide; Borisov, Kiril; Coey, J. M. D.; Stamenov, Plamen; Rode, Karsten

    2015-03-23

    Spin-dependent transport properties of Mn{sub 2}Ru{sub x}Ga thin-films are studied as function of the Ru concentration and the substrate-induced strain. The large spontaneous Hall angle of 7.7% twenty times bigger than in other 3d metals is a signature of its half-metallicity. The compensation temperature where the magnetization of the two inequivalent antiferromagnetically coupled Mn sublattices cancel can be tuned by varying x or the biaxial strain. This zero-moment half metal is free from demagnetizing forces and creates no stray field, effectively removing two obstacles to integrating magnetic elements in densely packed, nanometer-scale memory elements, and millimeter-wave generators.

  14. Enhanced magnetic hysteresis in Ni-Mn-Ga single crystal and its influence on magnetic shape memory effect

    SciTech Connect (OSTI)

    Heczko, O. Drahokoupil, J.; Straka, L.

    2015-05-07

    Enhanced magnetic hysteresis due to boron doping in combination with magnetic shape memory effect in Ni-Mn-Ga single crystal results in new interesting functionality of magnetic shape memory (MSM) alloys such as mechanical demagnetization. In Ni{sub 50.0}Mn{sub 28.5}Ga{sub 21.5} single crystal, the boron doping increased magnetic coercivity from few Oe to 270?Oe while not affecting the transformation behavior and 10?M martensite structure. However, the magnetic field needed for MSM effect also increased in doped sample. The magnetic behavior is compared to undoped single crystal of similar composition. The evidence from the X-ray diffraction, magnetic domain structure, magnetization loops, and temperature evolution of the magnetic coercivity points out that the enhanced hysteresis is caused by stress-induced anisotropy.

  15. Extended investigation of intermartensitic transitions in Ni-Mn-Ga magnetic shape memory alloys: A detailed phase diagram determination

    SciTech Connect (OSTI)

    akir, Asli; Aktrk, Seluk; Righi, Lara

    2013-11-14

    Martensitic transitions in shape memory Ni-Mn-Ga Heusler alloys take place between a high temperature austenite and a low temperature martensite phase. However, intermartensitic transformations have also been encountered that occur from one martensite phase to another. To examine intermartensitic transitions in magnetic shape memory alloys in detail, we carried out temperature dependent magnetization, resistivity, and x-ray diffraction measurements to investigate the intermartensitic transition in Ni{sub 50}Mn{sub 50x}Ga{sub x} in the composition range 12?x?25 at. %. Rietveld refined x-ray diffraction results are found to be consistent with magnetization and resistivity data. Depending on composition, we observe that intermartensitic transitions occur in the sequences 7M?L1{sub 0},?5M?7M, and 5M?7M?L1{sub 0} with decreasing temperature. The L1{sub 0} non-modulated structure is most stable at low temperature.

  16. Magneto-transport properties of oriented Mn{sub 2}CoAl films sputtered on thermally oxidized Si substrates

    SciTech Connect (OSTI)

    Xu, G. Z.; Du, Y.; Zhang, X. M.; Liu, E. K.; Wang, W. H. Wu, G. H.; Zhang, H. G.

    2014-06-16

    Spin gapless semiconductors are interesting family of materials by embracing both magnetism and semiconducting due to their unique band structure. Its potential application in future spintronics requires realization in thin film form. In this Letter, we report fabrication and transport properties of spin gapless Mn{sub 2}CoAl films prepared on thermally oxidized Si substrates by magnetron sputtering deposition. The films deposited at 673 K are well oriented to (001) direction and display a uniform-crystalline surface. Magnetotransport measurements on the oriented films reveal a semiconducting-like resistivity, small anomalous Hall conductivity, and linear magnetoresistance representative of the transport signatures of spin gapless semiconductors. The magnetic properties of the films have also been investigated and compared to that of bulk Mn{sub 2}CoAl, showing small discrepancy induced by the composition deviation.

  17. Alternating magnetic anisotropy of Li2(Li1xTx)N(T=Mn,Fe,Co,andNi)

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

    Jesche, A.; Ke, L.; Jacobs, J. L.; Harmon, B.; Houk, R. S.; Canfield, P. C.

    2015-05-11

    Substantial amounts of the transition metals Mn, Fe, Co, and Ni can be substituted for Li in single crystalline Li2(Li1xTx)N. Isothermal and temperature-dependent magnetization measurements reveal local magnetic moments with magnitudes significantly exceeding the spin-only value. The additional contributions stem from unquenched orbital moments that lead to rare-earth-like behavior of the magnetic properties. Accordingly, extremely large magnetic anisotropies have been found. Most notably, the magnetic anisotropy alternates as easy plane?easy axis?easy plane?easy axis when progressing from T = Mn ? Fe ? Co ? Ni. This behavior can be understood based on a perturbation approach in an analytical, single-ion model.moreAs a result, the calculated magnetic anisotropies show surprisingly good agreement with the experiment and capture the basic features observed for the different transition metals.less

  18. Temperature-induced martensite in magnetic shape memory Fe{sub 2}MnGa observed by photoemission electron microscopy

    SciTech Connect (OSTI)

    Jenkins, Catherine; Scholl, Andreas; Kainuma, R.; Elmers, Hans-Joachim; Omori, Toshihiro

    2012-01-18

    The magnetic domain structure in single crystals of a Heusler shape memory compound near the composition Fe{sub 2}MnGa was observed during phase transition by photoelectron emission microscopy at Beamline 11.0.1.1 of the Advanced Light Source. The behavior is comparable with recent observations of an adaptive martensite phase in prototype Ni{sub 2}MnGa, although the pinning in the recent work is an epitaxial interface and in this work the e#11;ective pinning plane is a boundary between martensitic variants that transform in a self-accommodating way from the single crystal austenite phase present at high temperatures. Temperature dependent observations of the twinning structure give information as to the coupling behavior between the magnetism and the structural evolution.

  19. Solvothermal synthesis of Zn{sub 2}GeO{sub 4}:Mn{sup 2+} nanophosphor in water/diethylene glycol system

    SciTech Connect (OSTI)

    Takeshita, Satoru; Honda, Joji; Isobe, Tetsuhiko; Sawayama, Tomohiro; Niikura, Seiji

    2012-05-15

    The influence of aging of the suspension containing the amorphous precusors on structural, compositional and photoluminescent properties is studied to understand the mechanism on the formation of Zn{sub 2}GeO{sub 4}:Mn{sup 2+} nanoparticles during the solvothermal reaction in the water/diethylene glycol mixed solvent. Aging at 200 Degree-Sign C for 20 min forms the crystalline Zn{sub 2}GeO{sub 4} nanorods and then they grow up to {approx} 50 nm in mean length after aging for 240 min. Their interplanar spacing of (410) increases with increasing the aging time. The photoluminescence intensity corresponding to the d-d transition of Mn{sup 2+} increases with increasing the aging time up to 120 min, and then decreases after aging for 240 min. The photoluminescence lifetime decreases with increasing the aging time, indicating the locally concentrated Mn{sup 2+} ions. These results reveal that Mn{sup 2+} ions gradually replace Zn{sup 2+} ions near surface through repeating dissolusion and precipitation processes during prolonged aging after the complete crystallization of Zn{sub 2}GeO{sub 4}. - Graphical abstract: TEM images of Zn{sub 2}GeO{sub 4}:Mn{sup 2+} nanoparticles aged at 200 Degree-Sign C for different aging times in the mixed solvent of water and diethylene glycol. Highlights: Black-Right-Pointing-Pointer Mechanism on formation of Zn{sub 2}GeO{sub 4}:Mn{sup 2+} nanophosphor under solvothermal condition. Black-Right-Pointing-Pointer Zn{sub 2}GeO{sub 4} nanorods crystallize via amorphous precursors. Black-Right-Pointing-Pointer Gradual substitution of Mn{sup 2+} during prolonged aging. Black-Right-Pointing-Pointer Such an inhomogeneous Mn{sup 2+} doping process results in concentration quenching.

  20. Characterization of precipitation behaviors in a non-stoichiometric Cu-24.5at.%Al-19.4at.%Mn alloy

    SciTech Connect (OSTI)

    Jeng, S.C.

    2011-02-15

    Scanning and transmission electron microscopy examinations of Cu-24.5at.% Al-19.4at.%Mn (similar to Cu{sub 2.2}Mn{sub 0.8}Al) alloy were performed after aging at temperatures ranging from 350 deg. C to 700 deg. C for various durations. It was observed that only {gamma}-brass type and L-J phases were formed after aging at or below 400 deg. C. On the other hand, the {beta}-Mn phase was formed after aging at temperatures ranging from 500 deg. C to 650 deg. C. It is noteworthy that the precipitation behaviors of the {gamma}-brass type and {beta}-Mn phases are different at different aging temperatures. This remarkable result differs from those reported in previous studies on the Cu{sub 3-X}Mn{sub X}Al alloys with X {<=} 1. - Research Highlights: {yields}Precipitation behaviors in a Cu{sub 2.2}Mn{sub 0.8}Al alloy shows different results from those reported in previous studies on the Cu-A-lMn alloys. {yields}The {gamma}-brass type precipitate occurs at temperatures ranging from 350 deg. C to 500 deg. C revealing different precipitation characteristics. {yields}The {beta}-Mn phase formed after aging at 500 deg. C to 650 deg. C shows different precipitation behaviors as well. {yields}L-J phase having an orthorhombic structure could be always observed in the as-quenched and aged conditions.