Тип публикации: статья из журнала
Год издания: 2010
Идентификатор DOI: 10.1134/S1063776110040059
Ключевые слова: Diamagnetic response, Effective field, Heat capacities, High-T, Hysteretic dependence, Josephson, Low temperature heat capacities, Non-monotonic dependence, Nonmonotonic behaviors, Polycrystalline, Spatially inhomogeneous, Transport currents, Electric resistance, Hysteresis, Magnetic field effects, Magnetic flux, Magnetoelectronics, Magnetoresistance, Phase separation, Semiconductor metal boundaries, Specific heat, Superconducting magnets, Superconducting materials, Superconductivity, Transport properties, Magnetic materials
Аннотация: The transport properties (R(T) and R(H) dependences at various values of the transport current in magnetic fields up to 65 kOe) and low-temperature heat capacity in magnetic fields up to 90 kOe of the BaPb0.75Bi0.25O3 superconductor (T-C approximate to 11.3 K) are investigated with the goal of clarifying the mechanisms determining the nonmonotonic behavior and hysteresis of its magnetoresistance R(H). The type of R(H) hysteretic dependences for BaPb0.75Bi0.25O3 is analogous to that observed in granular high-T-c superconductors (HTSCs); however, unlike classical HTSC systems, the field width of the magnetoresistance hysteresis loop for polycrystalline BaPb0.75Bi0.25O3 depends on the transport current. This means that although the mechanisms responsible for the magnetoresistance hysteresis (the influence of the magnetic flux trapped in super-conducting regions on the effective field in Josephson interlayers) are identical in these objects, the transport current in BaPb0.75Bi0.25O3 may considerably affect the diamagnetic response of the superconductor. A considerable effect of transport current on the field in which the R(H) dependences have a peak and exhibit hysterestic properties is observed. Such a behavior can be adequately interpreted using the model of the spatially inhomogeneous superconductor-insulator state proposed by Gorbatsevich et al. [JETP Lett. 52, 95 (1990)]. The nonmonotonic dependence of quantity C/T (C is the heat capacity) on the magnetic field discovered in the present study also agrees with the conclusions based on this model.
Журнал: JOURNAL OF EXPERIMENTAL AND THEORETICAL PHYSICS
Выпуск журнала: Vol. 110, Is. 4
Номера страниц: 584-593
ISSN журнала: 10637761
Место издания: NEW YORK
Издатель: MAIK NAUKA/INTERPERIODICA/SPRINGER
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