Search Results - (Author, Cooperation:C. Uher)

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  1. 1
    L. D. Zhao ; G. Tan ; S. Hao ; J. He ; Y. Pei ; H. Chi ; H. Wang ; S. Gong ; H. Xu ; V. P. Dravid ; C. Uher ; G. J. Snyder ; C. Wolverton ; M. G. Kanatzidis
    American Association for the Advancement of Science (AAAS)
    Published 2015
    Staff View
    Publication Date:
    2015-11-28
    Publisher:
    American Association for the Advancement of Science (AAAS)
    Print ISSN:
    0036-8075
    Electronic ISSN:
    1095-9203
    Topics:
    Biology
    Chemistry and Pharmacology
    Computer Science
    Medicine
    Natural Sciences in General
    Physics
    Published by:
    http://www.aaas.org/

    Latest Papers from Table of Contents or Articles in Press
  2. 2
    Y. Kim ; J. Zhu ; B. Yeom ; M. Di Prima ; X. Su ; J. G. Kim ; S. J. Yoo ; C. Uher ; N. A. Kotov
    Nature Publishing Group (NPG)
    Published 2013
    Staff View
    Publication Date:
    2013-07-19
    Publisher:
    Nature Publishing Group (NPG)
    Print ISSN:
    0028-0836
    Electronic ISSN:
    1476-4687
    Topics:
    Biology
    Chemistry and Pharmacology
    Medicine
    Natural Sciences in General
    Physics
    Published by:
    http://www.nature.com/

    Latest Papers from Table of Contents or Articles in Press
  3. 3
    L. D. Zhao ; S. H. Lo ; Y. Zhang ; H. Sun ; G. Tan ; C. Uher ; C. Wolverton ; V. P. Dravid ; M. G. Kanatzidis
    Nature Publishing Group (NPG)
    Published 2014
    Staff View
    Publication Date:
    2014-04-18
    Publisher:
    Nature Publishing Group (NPG)
    Print ISSN:
    0028-0836
    Electronic ISSN:
    1476-4687
    Topics:
    Biology
    Chemistry and Pharmacology
    Medicine
    Natural Sciences in General
    Physics
    Published by:
    http://www.nature.com/

    Latest Papers from Table of Contents or Articles in Press
  4. 4
    Deng, R., Su, X., Zheng, Z., Liu, W., Yan, Y., Zhang, Q., Dravid, V. P., Uher, C., Kanatzidis, M. G., Tang, X.
    American Association for the Advancement of Science (AAAS)
    Published 2018
    Staff View
    Publication Date:
    2018-06-02
    Publisher:
    American Association for the Advancement of Science (AAAS)
    Electronic ISSN:
    2375-2548
    Topics:
    Natural Sciences in General
    Published by:
    http://www.aaas.org/

    Latest Papers from Table of Contents or Articles in Press
  5. 5
    Richardson, R. A. ; Peacor, S. D. ; Uher, C. ; Nori, Franco

    [S.l.] : American Institute of Physics (AIP)
    Published 1992
    Staff View
    ISSN:
    1089-7550
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    We estimate the phonon mean-free path (mfp) in YBa2Cu3O7−δ by performing a theoretical fitting procedure on bulk single-crystal data. This analysis indicates that the mfps of the phonons that are most responsible for the transport of heat are much longer than would be predicted from kinetic theory. These values are incorporated into a recently proposed treatment of the size effect to provide an estimate of the thermal conductivity of YBa2Cu3O7−δ films.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.352091

    Articles: DFG German National Licenses
  6. 6
    Clarke, Roy ; Elagoz, S. ; Vavra, W. ; Schuler, E. ; Uher, C.

    [S.l.] : American Institute of Physics (AIP)
    Published 1991
    Staff View
    ISSN:
    1089-7550
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    We explore the relationship between interface structure and magnetic anisotropy in three types of Co-based superlattices: Cohcp-Au; Cofcc-Cu; and Cohcp-Cr, grown epitaxially on GaAs(110). For very thin layers of Co, Co-Au, and Co-Cu superlattices exhibit a perpendicular easy axis due to magnetoelastic contributions to the anisotropy energy. The magnetic anisotropy in Co-Cr is found to be strongly dependent on growth conditions. At slow deposition rates of Co the interface between Co and Cr becomes diffuse as is evidenced by a low saturation moment and a shift toward perpendicular anisotropy whereas samples with abrupt interfaces show predominantly parallel anisotropy. The Cr layers grow in a metastable hcp phase which appears to be paramagnetic. The results illustrate the influence of the heterointerface on magnetic properties.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.350157

    Articles: DFG German National Licenses
  7. 7
    Chwalek, J. M. ; Uher, C. ; Whitaker, J. F. ; Mourou, G. A. ; Agostinelli, J. A.

    Woodbury, NY : American Institute of Physics (AIP)
    Published 1991
    Staff View
    ISSN:
    1077-3118
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    We report the results of the first time-resolved observation of impulsively generated coherent optical phonon oscillations in the semiconducting cuprate compound YBa2Cu3O6+x (x〈0.4). The oscillations, which were probed through time-resolved transmissivity modulation, had a period of 237 fs at room temperature, corresponding to a Raman active mode of A1g symmetry at 142 cm−1. No oscillations were observed in the superconducting form of Y-Ba-Cu-O either above or below Tc. The amplitude, frequency, and linewidth of this mode were measured over a temperature range from ∼7 K to room temperature.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.104462

    Articles: DFG German National Licenses
  8. 8
    Shewchun, J. ; Chen, Yi ; Hölder, J. S. ; Uher, C.

    Woodbury, NY : American Institute of Physics (AIP)
    Published 1991
    Staff View
    ISSN:
    1077-3118
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    By depositing a buffer layer of Al2O3 on GaAs, we have been able to laser ablate a superconducting film of Y1Ba2Cu3O7−x overtop. The onset of superconductivity is 92 K and zero resistance is observed at 80 K in a structure with a suitably annealed Al2O3 film which is converted to AlGaO3. Both the Al2O3-GaAs and the Al2O3-Y1Ba2Cu3O7−x interfaces are remarkably well preserved with virtually no interdiffusion or interaction. The Al2O3 or homolog AlGaO3 film also prevents decomposition of the GaAs at the deposition temperature of 730 °C.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.104789

    Articles: DFG German National Licenses
  9. 9
    Chwalek, J. M. ; Uher, C. ; Whitaker, J. F. ; Mourou, G. A. ; Agostinelli, J. ; Lelental, M.

    Woodbury, NY : American Institute of Physics (AIP)
    Published 1990
    Staff View
    ISSN:
    1077-3118
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    We report the results of femtosecond optical transient absorption experiments performed on 〈m1;&1p〉the superconducting compounds YBa2Cu3O7−x(x ∼ 0) and Bi2Sr2Ca2Cu3O10+δ(δ ∼ 0) and nonsuperconducting YBa2Cu3O6+y(y〈0.4) for sample temperatures ranging from ∼7 K to room temperature. Nonequilibrium heating was found to occur on a subpicosecond time scale. A distinct, dramatic increase in the relaxation time was observed for the superconducting samples as the sample temperature was lowered below the critical temperatures of the respective films. Accompanying the increase in relaxation time was an increase in the peak fractional transmissivity change. No such changes were observed for the nonsuperconducting YBCO sample. We believe the above described behavior is electronic in origin and intimately related to the superconductivity of the compounds.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.104140

    Articles: DFG German National Licenses
  10. 10
    Morelli, D. T. ; Uher, C. ; Robinson, C. J.

    Woodbury, NY : American Institute of Physics (AIP)
    Published 1993
    Staff View
    ISSN:
    1077-3118
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    The influence of grain boundary scattering of lattice waves in high quality diamond films has been determined by the measurement of thermal conductivity down to 0.15 K. We find that the mean free path for lattice vibrations (phonons) exceeds substantially the crystallite size and approaches the physical size of the sample. This implies that a significant transmission of phonons occurs between the grains of these polycrystalline diamond materials.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.108802

    Articles: DFG German National Licenses
  11. 11
    Lukaszew, R. A. ; Sheng, Y. ; Uher, C. ; Clarke, R.

    Woodbury, NY : American Institute of Physics (AIP)
    Published 1999
    Staff View
    ISSN:
    1077-3118
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    Epitaxial growth techniques are used to impose in-plane magnetocrystalline anisotropy on a spin-polarized tunneling configuration. A Cu(100) buffer layer grown on a Si(100) substrate stabilizes epitaxial face-centered-cubic cobalt as one of the ferromagnetic electrodes. The negative magnetocrystalline constant of this metastable phase favors easy axes along Co 〈110〉 and, due to the single crystal nature of this layer, the coercivity is more than an order of magnitude larger than in the polycrystalline layers which form the second electrode. Our approach provides a way to access the high degree of spin polarization characteristic of the 3d transition metals. © 1999 American Institute of Physics.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.124878

    Articles: DFG German National Licenses
  12. 12
    Lukaszew, R. A. ; Sheng, Y. ; Uher, C. ; Clarke, R.

    Woodbury, NY : American Institute of Physics (AIP)
    Published 2000
    Staff View
    ISSN:
    1077-3118
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    We report an in situ study of the molecular-beam epitaxy growth and annealing of Cu(001) films grown on hydrogen-terminated Si(001) substrates, resulting in a promising approach to achieve smooth epitaxial morphology. Using correlated reflection high-energy electron diffraction and scanning tunneling microscopy data, we find a temperature interval below the onset of silicide formation where a dramatic smoothening of the epitaxial Cu surfaces occurs. Our measurements indicate that a reduction in roughness is possible in this regime because the annealing is controlled by lateral diffusion kinetics. © 2000 American Institute of Physics.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.125874

    Articles: DFG German National Licenses
  13. 13
    Peacor, S. D. ; Uher, C. ; Francis, A. H. ; Shewchun, J.

    [S.l.] : American Institute of Physics (AIP)
    Published 1990
    Staff View
    ISSN:
    1089-7550
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    The physical and electromagnetic properties of Y-Ba-Cu-O superconductors synthesized with BaO2 (barium peroxide) have been studied. A comparison of reactions with BaCO3 and BaO indicates that the peroxide promotes formation and strong alignment of platelet grains in planes normal to the c axis, yields material with larger grain sizes and aspect ratios, reduces the synthesis reaction time by over half, increases the volume fraction of material that goes superconducting (Meissner effect), and facilitates metallic conduction in the normal state. Critical current densities of 1.1×104 A/cm2 at 77 K have been observed in peroxide-synthesized material. These beneficial effects may be due to the low melting temperature of BaO2 (450 °C), and the elimination of residual unreacted BaCO3, BaO, and/or C.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.345835

    Articles: DFG German National Licenses
  14. 14
    Cohn, J. L. ; Uher, C.

    [S.l.] : American Institute of Physics (AIP)
    Published 1989
    Staff View
    ISSN:
    1089-7550
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    We report on the electrical resistance and time-dependent oxidation of thin ((approximately-less-than)90 A(ring)) semicontinuous bismuth films. An increase in the room temperature sheet resistance with exposure to air is correlated with the growth of insulating Bi2O3 at the surfaces and internal boundaries between bismuth particles. For short oxidation times t, the resistance increases as R(D'Alembertian) ∝t1/2, consistent with a parabolic oxide growth law. At longer times the resistance follows the classical percolation law R(D'Alembertian)∝||tc−t||−μ, where tc is a critical exposure time and μ(approximately-equal-to)1.3 is a critical exponent for two-dimensional systems.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.344344

    Articles: DFG German National Licenses
  15. 15
    Uher, C. ; Peacor, S.D. ; Shewchun, J.

    Amsterdam : Elsevier
    Staff View
    ISSN:
    0921-4534
    Source:
    Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics:
    Physics
    Type of Medium:
    Electronic Resource
    URL:
    http://linkinghub.elsevier.com/retrieve/pii/0921-4534(91)90291-6

    Articles: DFG German National Licenses
  16. 16
    Uher, C.

    Amsterdam : Elsevier
    Staff View
    ISSN:
    0022-0248
    Source:
    Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics:
    Chemistry and Pharmacology
    Geosciences
    Physics
    Type of Medium:
    Electronic Resource
    URL:
    http://linkinghub.elsevier.com/retrieve/pii/0022-0248(83)90017-9

    Articles: DFG German National Licenses
  17. 17
    Staff View
    ISSN:
    0038-1098
    Source:
    Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics:
    Physics
    Type of Medium:
    Electronic Resource
    URL:
    http://linkinghub.elsevier.com/retrieve/pii/0038-1098(91)90573-E

    Articles: DFG German National Licenses
  18. 18
    Uher, C. ; Lee, C.-W. ; Bass, J.

    Amsterdam : Elsevier
    Staff View
    ISSN:
    0375-9601
    Source:
    Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics:
    Physics
    Type of Medium:
    Electronic Resource
    URL:
    http://linkinghub.elsevier.com/retrieve/pii/0375-9601(77)90637-5

    Articles: DFG German National Licenses
  19. 19
    Uher, C. ; Kaiser, A.B.

    Amsterdam : Elsevier
    Staff View
    ISSN:
    0375-9601
    Source:
    Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics:
    Physics
    Type of Medium:
    Electronic Resource
    URL:
    http://linkinghub.elsevier.com/retrieve/pii/0375-9601(87)90175-7

    Articles: DFG German National Licenses
  20. 20
    Pratt, W.P. ; Uher, C.

    Amsterdam : Elsevier
    Staff View
    ISSN:
    0375-9601
    Source:
    Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics:
    Physics
    Type of Medium:
    Electronic Resource
    URL:
    http://linkinghub.elsevier.com/retrieve/pii/0375-9601(78)90762-4

    Articles: DFG German National Licenses