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Magnetoresistance hysteresis in granular HTSCs as a manifestation of the magnetic flux trapped by superconducting grains in YBCO + CuO composites

Journal Article · · Journal of Experimental and Theoretical Physics
; ; ; ;  [1]
  1. Russian Academy of Sciences, Kirenskii Institute of Physics, Siberian Branch (Russian Federation)
Hysterestic behavior of the magnetoresistance of granular HTSCs and its interaction with the magnetic hysteresis are studied by measuring magnetoresistance R(H) and critical current I{sub c}(H) of composites formed by HTSC Y{sub 0.75}Lu{sub 0.25}Ba{sub 2}Cu{sub 3}O{sub 7} and CuO. A network of Josephson junctions is formed in such composites, in which the nonsuperconducting component plays the role of barriers between HTSC grains. Hysteretic dependences R(H) of magnetoresistance are studied in a wide range of transport current density j and are analyzed in the framework of the two-level model of a granular superconductor, in which dissipation takes place in the Josephson medium and the magnetic flux can be pinned both in grains and in the Josephson medium. The interrelation between the hysteresis of critical current I{sub c}(H) and the evolution of the hysterestic dependence R(H) of the magnetoresistance upon transport current variation is demonstrated experimentally. The effect of the magnetic past history on the hysteretic behavior of R(H) and the emergence of a segment with a negative magnetoresistance are analyzed. It is shown for the first time that the R(H) dependences are characterized by a parameter that is independent of the transport current, viz., the width of the R(H) hysteresis loop.
OSTI ID:
21075646
Journal Information:
Journal of Experimental and Theoretical Physics, Journal Name: Journal of Experimental and Theoretical Physics Journal Issue: 6 Vol. 105; ISSN JTPHES; ISSN 1063-7761
Country of Publication:
United States
Language:
English