Search Results - (Author, Cooperation:A. Kapitulnik)

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  1. 1
    Staff View
    Publication Date:
    2018-05-05
    Publisher:
    American Physical Society (APS)
    Print ISSN:
    0031-9007
    Electronic ISSN:
    1079-7114
    Topics:
    Physics
    Keywords:
    Condensed Matter: Electronic Properties, etc.
    Published by:
    http://www.aps.org/

    Latest Papers from Table of Contents or Articles in Press
  2. 2
    E. R. Schemm ; W. J. Gannon ; C. M. Wishne ; W. P. Halperin ; A. Kapitulnik
    American Association for the Advancement of Science (AAAS)
    Published 2014
    Staff View
    Publication Date:
    2014-07-12
    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
  3. 3
    Staff View
    Publication Date:
    2011-03-26
    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
  4. 4
    Fang, A., Adamo, C., Jia, S., Cava, R. J., Wu, S.-C., Felser, C., Kapitulnik, A.
    American Association for the Advancement of Science (AAAS)
    Published 2018
    Staff View
    Publication Date:
    2018-04-14
    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
    Spielman, S. ; Fesler, K. ; Eom, C. B. ; Geballe, T. H. ; Fejer, M. M. ; Kapitulnik, A.

    [S.l.] : American Institute of Physics (AIP)
    Published 1991
    Staff View
    ISSN:
    1089-7550
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    We have modifed a fiber-optic gyroscope based on the Sagnac interferometer to measure nonreciprocal phase shifts. The instrument has a sensitivity of better than 1 μrad and is insensitive to any reciprocal phase shifts. Thin films of high-temperature superconductors (HTSC) have been measured in search for nonreciprocal effects below Tc due to "Anyon superconductivity'' ground state. No nonreciprocal phase shift was observed in any of the measured samples.1 The Faraday effect in various magnetic thin films (e.g., EuO) have been measured using the instrument showing a great sensitivity to submonolayers of the materials.〈ks〉
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.348141

    Articles: DFG German National Licenses
  6. 6
    Marshall, A. F. ; Klein, L. ; Dodge, J. S. ; Ahn, C. H. ; Reiner, J. W. ; Mieville, L. ; Antagonazza, L. ; Kapitulnik, A. ; Geballe, T. H. ; Beasley, M. R.

    [S.l.] : American Institute of Physics (AIP)
    Published 1999
    Staff View
    ISSN:
    1089-7550
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    The magnetic microstructure of SrRuO3 thin films is studied using Lorentz transmission electron microscopy (TEM). The zero-field-cooled magnetic stripe structure shows one-to-one correlation with the crystal domain structure and is used to identify the uniaxial magnetic anisotropy of these films, consistent with results on single domain films. The anisotropy is shown to be primarily magnetocrystalline in nature with the b axis as the easy axis. Lorentz TEM also yields quantitative information about the domain structure and domain wall resistivity, and allows for in situ observation of domain wall formation and dynamic response to an applied field. © 1999 American Institute of Physics.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.370322

    Articles: DFG German National Licenses
  7. 7
    Wu, X. D. ; Kino, G. S. ; Fanton, J. T. ; Kapitulnik, A.

    [S.l.] : American Institute of Physics (AIP)
    Published 1993
    Staff View
    ISSN:
    1089-7623
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Electrical Engineering, Measurement and Control Technology
    Notes:
    We have developed a new photothermal technique to investigate electronic phase transitions associated with high temperature superconductivity and charge density waves (CDW). The phase shift of the thermal wave yields the anisotropic thermal diffusivity coefficient of the sample. The amplitude of the photothermal signal is sensitive to electronic phase transitions of the second kind and measures directly the effect of thermodynamic fluctuations near the transitions. This noncontacting high-definition technique is well suited to measurements of small and fragile samples. Good comparisons between our experimental results and second-order phase transition theory are obtained on a high-Tc superconductor and a CDW sample.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.1144298

    Articles: DFG German National Licenses
  8. 8
    Dodge, J. S. ; Klein, L. ; Fejer, M. M. ; Kapitulnik, A.

    [S.l.] : American Institute of Physics (AIP)
    Published 1996
    Staff View
    ISSN:
    1089-7550
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    We demonstrate the application of the Sagnac interferometer to magneto-optic measurements at an oblique angle of incidence. With an appropriate choice of polarization states for the two counter-propagating beams, a wide variety of magneto-optic effects may be measured, in the absence of an external perturbing field, with a sensitivity of a few hundred nanoradians. Using simple symmetry analysis of the conventional Kerr rotation measurement geometry, we may distinguish contributions to the non-reciprocal phase shift due to the polar, longitudinal and transverse Kerr effects, and consequently completely determine the magnetization vector direction, averaged over the probed region. Magneto-optic hysteresis loops were taken on a permalloy film to demonstrate the effectiveness of the new technique. We discuss the relevance of the Sagnac interferometer to magnetic microscopy and to the study of magnetic anisotropies in thin films. © 1996 American Institute of Physics.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.362567

    Articles: DFG German National Licenses
  9. 9
    Kapitulnik, A. ; Dodge, J. S. ; Fejer, M. M.

    [S.l.] : American Institute of Physics (AIP)
    Published 1994
    Staff View
    ISSN:
    1089-7550
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    A technique for measuring the Faraday effect and the magneto-optic Kerr effect has been developed. In a Sagnac interferometer, two optical beams follow identical paths in opposite directions. Effects which break time-reversal symmetry, such as magneto-optic effects, will cause destructive interference between the two beams. By measuring the phase shift between circular polarization states reflected from a magnetized sample, the polar magneto-optic Kerr effect is measured to an accuracy of 3 μrad, with a spatial resolution of 2 μm. The interferometric technique provides a number of advantages over conventional polarizer methods, including insensitivity to linear birefringence, the ability to completely determine the magnetization vector in a region, and the ability to sensitively measure magneto-optic effects without an external field. It is also shown that this device has great potential if incorporated into a near-field optical device. Some of the considerations for the design of a near-field Sagnac magneto-optic sensor are introduced and the advantages of the device are discussed. Some preliminary experiments are shown.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.356814

    Articles: DFG German National Licenses
  10. 10
    Dessau, D. S. ; Wells, B. O. ; Shen, Z.-X. ; Spicer, W. E. ; Arko, A. J. ; List, R. S. ; Olson, C. G. ; Eom, C. B. ; Mitzi, D. B. ; Kapitulnik, A. ; Geballe, T. H.

    Woodbury, NY : American Institute of Physics (AIP)
    Published 1991
    Staff View
    ISSN:
    1077-3118
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    We have used high-resolution photoemission spectroscopy to search for a proximity effect induced superconducting gap in gold overlayers on c-axis single crystals of Bi2Sr2CaCu2O8 and a-axis thin films of YBa2Cu3O7. These two junction types give us a representative sampling of very well characterized near-ideal interfaces (gold/c-axis Bi2Sr2CaCu2O8) and junctions in which the geometry more strongly favors the existence of the proximity effect but the interfacial quality may not be as ideal (gold/a-axis YBa2Cu3O7). In neither of these junction types did we observe any evidence for a proximity effect induced gap, and we place an upper limit of approximately 5 meV on its existence in the junctions that we have studied.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.104301

    Articles: DFG German National Licenses
  11. 11
    Kim, J. H. ; Char, K. ; Bozovic, I. ; Lee, W. Y. ; Kapitulnik, A. ; Harris, J. S.

    Woodbury, NY : American Institute of Physics (AIP)
    Published 1991
    Staff View
    ISSN:
    1077-3118
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    We report optical reflectivity data of several representative high Tc superconducting films before and after ion milling. A significant enhancement of optical reflectivity after ion milling of a few thousand A(ring) is observed. We observed that features associated with a-axis texture vanished after ion milling, resulting in pure c-axis films. This suggests that a-axis grains reside mostly near the surface in post-annealed high Tc superconducting films. The fact that highly oriented c-axis films can be retained even after post-annealing (for raising Tc) may be important for practical applications.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.104825

    Articles: DFG German National Licenses
  12. 12
    Dessau, D. S. ; Shen, Z.-X. ; Wells, B. O. ; Spicer, W. E. ; List, R. S. ; Arko, A. J. ; Bartlett, R. J. ; Fisk, Z. ; Cheong, S-W. ; Mitzi, D. B. ; Kapitulnik, A. ; Schirber, J. E.

    Woodbury, NY : American Institute of Physics (AIP)
    Published 1990
    Staff View
    ISSN:
    1077-3118
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    High-resolution photoemission has been used to probe the electronic structure of the gold/Bi2Sr2CaCu2O8 and gold/EuBa2Cu3O7−δ interface formed by a low-temperature (20 K) gold evaporation on cleaved high quality single crystals. We find that the metallicity of the EuBa2Cu3O7−δ substrate in the near surface region (∼5 A(ring)) is essentially destroyed by the gold deposition, while the near surface region of Bi2Sr2CaCu2O8 remains metallic. This has potentially wide ranging consequences for the applicability of the different types of superconductors in real devices.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.104219

    Articles: DFG German National Licenses
  13. 13
    Fanton, J. T. ; Mitzi, D. B. ; Kapitulnik, A. ; Khuri-Yakub, B. T. ; Kino, G. S. ; Gazit, D. ; Feigelson, R. S.

    Woodbury, NY : American Institute of Physics (AIP)
    Published 1989
    Staff View
    ISSN:
    1077-3118
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    We demonstrate a photothermal method for making point measurements of the thermal conductivities of high Tc superconductors. Images made at room temperature on polycrystalline materials show the thermal inhomogeneities. Measurements on single-crystal Bi2Sr2CaCu2Ox compounds reveal a very large anisotropy of about 7:1 in the thermal conductivity.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.101843

    Articles: DFG German National Licenses
  14. 14
    Webb, C. ; Weng, S.-L. ; Eckstein, J. N. ; Missert, N. ; Char, K. ; Schlom, D. G. ; Hellman, E. S. ; Beasley, M. R. ; Kapitulnik, A. ; Harris, J. S.

    Woodbury, NY : American Institute of Physics (AIP)
    Published 1987
    Staff View
    ISSN:
    1077-3118
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    Thin films of the high-temperature superconductor DyBa2Cu3O7−x have been grown on SrTiO3 substrates using molecular beam epitaxy techniques. Reflection high-energy electron diffraction patterns observed during deposition indicate incomplete oxidation of copper and growth of oriented metallic copper microcrystals in a matrix of amorphous barium and dysprosium oxides. After post-growth anneal the films exhibited sharp superconducting transitions with zero resistance observed as high as 89 K and critical current densities of 4.8×105 A/cm2 at 4.2 K and 3.9×104 A/cm2 at 77 K.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.98729

    Articles: DFG German National Licenses
  15. 15
    Lindberg, P. A. P. ; Shen, Z.-X. ; Wells, B. O. ; Mitzi, D. B. ; Lindau, I. ; Spicer, W. E. ; Kapitulnik, A.

    Woodbury, NY : American Institute of Physics (AIP)
    Published 1988
    Staff View
    ISSN:
    1077-3118
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    The surface structure of Bi2Sr2CaCu2O8+δ has been studied using low-energy electron diffraction (LEED). Sharp diffraction spots indicative of a well-ordered surface are observed. The LEED patterns unequivocally show that this type of material preferentially cleaves along the a-b planes of the nearly tetragonal unit cell. A superstructure extending along one of the axes in the a-b plane (b) is found to have a periodicity of 27±0.5 A(ring), in good agreement with earlier studies of the three-dimensional crystal structure. We conclude that the superstructure at the surface is nonlocal in character and reflects the long-range superlattice of the bulk along the b axis. Intensity modulations of the diffraction spots oriented along the b axis are also reported and discussed in terms of the cell dimension of the unit cell along the b axis.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.100532

    Articles: DFG German National Licenses
  16. 16
    Marshall, A. F. ; Oh, B. ; Spielman, S. ; Lee, Mark ; Eom, C. B. ; Barton, R. W. ; Hammond, R. H. ; Kapitulnik, A. ; Beasley, M. R. ; Geballe, T. H.

    Woodbury, NY : American Institute of Physics (AIP)
    Published 1988
    Staff View
    ISSN:
    1077-3118
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    Thin films of Bi-Ca-Sr-Cu-O showing superconductivity above 100 K have been made by electron beam evaporation with oxygen post-annealing. The major superconducting phase, Bi2[Ca,Sr]3Cu2O8+δ (Tc ∼85 K), is oriented epitaxially with the (100)SrTiO3 substrate. In addition to the one-dimensional incommensurate superstructure along the b axis, which is characteristic of this phase, we have observed by transmission electron microscopy a two-dimensional incommensurate superstructure in the a-b plane with a different periodicity and a different orientation relationship to the subcell.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.100610

    Articles: DFG German National Licenses
  17. 17
    Hylton, T. L. ; Kapitulnik, A. ; Beasley, M. R. ; Carini, John P. ; Drabeck, L. ; Grüner, George

    Woodbury, NY : American Institute of Physics (AIP)
    Published 1988
    Staff View
    ISSN:
    1077-3118
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    We propose a model of Josephson coupling between grains to explain the millimeter-wave surface impedance of oriented, polycrystalline thin films of high Tc superconductors. An effective junction IcR product and effective grain size are calculated based on recent measurements of the surface impedance. We suggest a criterion on film quality for the observation of losses intrinsic in the superconductor. The effects of crystalline orientation on surface impedance are considered.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.99976

    Articles: DFG German National Licenses
  18. 18
    Kirk, M. D. ; Eom, C. B. ; Oh, B. ; Spielman, S. R. ; Beasley, M. R. ; Kapitulnik, A. ; Geballe, T. H. ; Quate, C. F.

    Woodbury, NY : American Institute of Physics (AIP)
    Published 1988
    Staff View
    ISSN:
    1077-3118
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    A scanning tunneling microscope was used to image the a-b plane of a single crystal of Bi2(Ca,Sr)3Cu2O8+δ (Tc∼85 K) and a thin film grown epitaxially on a (100) SrTiO3 substrate. Images taken at room temperature in air of a freshly cleaved bulk sample clearly show the one-dimensional superstructure (27.2±0.7 A(ring) periodicity) which is common to this phase. Several images show steps 16 A(ring) high, suggesting that the cleavage occurs between 2122 molecular units. The registry of the superstructure from terrace to terrace is either shifted by half a superlattice parameter or is aligned. Images of evaporated thin films show features of comparable size, but not the same long-range order as the crystal. Low-temperature conductance measurements of the thin film exhibit a BCS-like energy gap with 2Δ/kTc≈12.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.99750

    Articles: DFG German National Licenses
  19. 19
    Sun, J. Z. ; Char, K. ; Hahn, M. R. ; Geballe, T. H. ; Kapitulnik, A.

    Woodbury, NY : American Institute of Physics (AIP)
    Published 1989
    Staff View
    ISSN:
    1077-3118
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    High Tc superconductors exhibit significant flux motion due to a thermally activated creep process. The motion of the fluxoids dissipates energy. This dissipation causes a broadening of the resistive transition below Tc in a magnetic field as well as a logarithmic decay of the diamagnetic shielding moment in time. From the detailed structure of the broadened transition, empirical parameters are derived. The pinning strength is highly anisotropic, reflecting the anisotropy of the coherence length. Implications of an extraordinarily low activation energy are also addressed.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.101465

    Articles: DFG German National Licenses
  20. 20
    Char, K. ; Kent, A. D. ; Kapitulnik, A. ; Beasley, M. R. ; Geballe, T. H.

    Woodbury, NY : American Institute of Physics (AIP)
    Published 1987
    Staff View
    ISSN:
    1077-3118
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    Superconducting thin films of YBa2Cu3O7−x have been successfully made by co-sputtering from the three targets in an Ar and O2 mixture atmosphere. After high-temperature anneal films are superconducting with an onset temperature at 90 K, a full transition temperature as high as 88 K, and a critical current density in excess of 1×105 A/cm2 at 78 K and 2×106 A/cm2 at 4.2 K. Highly oriented thin films have been obtained on SrTiO3 {100} substrates.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.98682

    Articles: DFG German National Licenses