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Author Herrmann, J. ♦ de Andrade, M. C. ♦ Almasan, C. C. ♦ Dickey, R. P. ♦ Maple, M. B. ♦ Jiang, W. ♦ Mao, S. N. ♦ Greene, R. L.
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword MATERIALS SCIENCE ♦ SUPERCONDUCTING FILMS ♦ MAGNETORESISTANCE ♦ PHASE STUDIES ♦ HIGH-TC SUPERCONDUCTORS ♦ CUPRATES ♦ CERIUM OXIDES ♦ NEODYMIUM OXIDES ♦ THIN FILMS ♦ STOICHIOMETRY ♦ EPITAXY ♦ ELECTRIC CONDUCTIVITY ♦ FLUCTUATIONS ♦ TYPE-II SUPERCONDUCTORS ♦ TEMPERATURE RANGE 0000-0013 K ♦ TEMPERATURE RANGE 0013-0065 K ♦ MAGNETIC FLUX ♦ COHERENCE LENGTH ♦ CRITICAL FIELD
Abstract We report measurements of the magnetoresistance of Nd{sub 1.85}Ce{sub 0.15}CuO{sub 4{plus_minus}{delta}} epitaxial thin films with varying oxygen content in magnetic fields {ital H} applied parallel ({ital H}{parallel}{ital c}) and perpendicular ({ital H}{perpendicular}{ital c}) to the tetragonal {ital c} axis. We have observed critical scaling of the electrical resistivity that is consistent with a vortex-glass transition for a film with an optimum superconducting transition temperature {ital T}{sub {ital c}} of {approx_equal}22 K and {ital H}{parallel}{ital c}. The values of the zero-temperature upper critical field {ital H}{sub {ital c}{sub 2}}(0)=80 kOe and the in-plane zero-temperature coherence length {xi}{sub {ital ab}}(0)=64 A were obtained from an analysis of the fluctuation conductivity. For an overoxygenated film with {ital T}{sub {ital c}}{approx_equal}10 K, an anomaly develops with increasing field for {ital H}{parallel}{ital c} and {ital T}{approx_lt}2 K that is characterized by a minimum in the temperature dependence of the resistivity followed by a second resistive transition at a lower temperature, which is nearly independent of {ital H}. This behavior is similar to that previously observed in Nd{sub 2{minus}{ital x}}Ce{sub {ital x}}CuO{sub 4{minus}{delta}} single crystals and may be associated with the magnetic ordering of the Nd{sup 3+} ions. {copyright} {ital 1996 The American Physical Society.}
ISSN 01631829
Educational Use Research
Learning Resource Type Article
Publisher Date 1996-08-01
Publisher Place United States
Journal Physical Review, B: Condensed Matter
Volume Number 54
Issue Number 5


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