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