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/ D. A. Balaev [et al.] // Phys. Solid State. - 2008. - Vol. 50, Is. 6. - P. 1014-1021, DOI 10.1134/S1063783408060036. - Cited References: 24 . - ISSN 1063-7834РУБ Physics, Condensed Matter

Аннотация: The hysteresis of magnetoresistance R(H) and relaxation of the remanent resistance R-rem with time after magnetic field treatment of HTSC (Y-Ba-Cu-O) + CuO composites are studied. Such a composite constitutes a network of Josephson junctions wherein the nonsuperconducting component (CuO) forms Josephson barriers between HTSC grains. By comparing the experimental R-rem(t) and R(H) dependences, it is shown that the relaxation of the remanent resistance is caused by the decreased magnetic field in the intergrain medium due to relaxation of magnetization. The reason is uncovered for the differences between the published values of pinning potentials determined by measuring the relaxation of magnetization or resistance and fitting them by the Anderson law.

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Держатели документа:
[Balaev, D. A.
Dubrovskii, A. A.
Popkov, S. I.
Shaikhutdinov, K. A.
Petrov, M. I.] Russian Acad Sci, Siberian Branch, LV Kirensky Phys Inst, Krasnoyarsk 660036, Russia
ИФ СО РАН
Kirensky Institute of Physics, Siberian Branch, Russian Academy of Sciences, Akademgorodok, Krasnoyarsk, 660036, Russian Federation

Доп.точки доступа:
Balaev, D. A.; Балаев, Дмитрий Александрович; Dubrovskii, A. A.; Дубровский, Андрей Александрович; Popkov, S. I.; Попков, Сергей Иванович; Shaikhutdinov, K. A.; Шайхутдинов, Кирилл Александрович; Petrov, M. I.; Петров, Михаил Иванович

/ D. A. Balaev [et al.] // Phys. Solid State. - 2006. - Vol. 48, Is. 5. - P. 826-832, DOI 10.1134/S1063783406050039. - Cited References: 32 . - ISSN 1063-7834РУБ Physics, Condensed Matter

Аннотация: This paper reports on the results of an investigation into the influence of magnetic fields (0-60 kOe) on the temperature dependences of the electrical resistance R(T) of the Y3/4Lu1/4Ba2Cu3O7 + CuO composites. The structure of these composites is considered to be a network of tunnel-type Josephson junctions in which a nonsuperconducting component (CuO) forms boundaries (barriers) between high-temperature superconducting crystallites. The temperature dependence R(T) of the composites has two steps characteristic of granular superconductors: (i) an abrupt change in the electrical resistance at the critical temperature of high-temperature superconducting crystallites and (ii) a smooth transition to the superconducting state under the influence of the boundaries between the crystallites. The experimental dependences R(T) are analyzed within the Ambegaokar-Halperin model of thermal fluctuations in Josephson junctions and the flux creep model. An increase in the magnetic field leads to a crossover from the Ambegaokar-Halperin mechanism to the flux creep mechanism. The temperature dependences R(T) in the range of weak magnetic fields (from 0 to 10(2) Oe) are adequately described by the relationship following from the Ambegaokar-Halperin model. In the range of strong magnetic fields (from 10(3) to 6 x 10(4) Oe), the dissipation obeys the Arrhenius law R similar to exp(-U(H)/T)], which is characteristic of the flux creep model with a temperature-independent pinning energy U(H). The effective Josephson coupling energies and the pinning energies corresponding to the Ambegaokar-Halperin and flux creep mechanisms are determined.

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Держатели документа:
Russian Acad Sci, Siberian Div, Kirensky Inst Phys, Krasnoyarsk 660036, Russia
ИФ СО РАН
Kirensky Institute of Physics, Siberian Division, Russian Academy of Sciences, Akademgorodok, Krasnoyarsk, 660036, Russian Federation

Доп.точки доступа:
Balaev, D. A.; Балаев, Дмитрий Александрович; Popkov, S. I.; Попков, Сергей Иванович; Shaikhutdinov, K. A.; Шайхутдинов, Кирилл Александрович; Petrov, M. I.; Петров, Михаил Иванович