Europhys. Lett, 34 (4), pp. 287-292 (1996)
Self-organized criticality effect on stability: magneto-thermal oscillations in a granular YBCO superconductor
L. Legrand , I. Rosenman , R. G. Mints , G. Collin and E. Janod
Groupe de Physique des Solides, Unité 17
Associée au CNRS, Universités Paris 6 et Paris 7 - Tour 23,
2 place Jussieu, 75251 Paris Cedex 5, France
School of Physics and Astronomy, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University - Tel Aviv 69978, Israel
Laboratoire Léon Brillouin, CEN-Saclay - 91191 Gif-sur-Yvette Cedex, France
DRFMC, CEA/Grenoble - 17 rue des Martyrs, 38054 Grenoble Cedex 9, France
(received 15 January 1996; accepted in final form 17 March 1996)
PACS. 74.60Ge - Flux pinning, flux creep, and flux-line lattice
PACS. 74.72Bk - Y-based compounds.
PACS. 74.80Bj - Granular, melt-textured, and amorphous superconductors; powders.
Abstract:We show that the self-organized criticality of Bean's state in each of the grains of a granular superconductor results in magneto-thermal oscillations. We find that the frequency of these oscillations is proportional to the external magnetic field sweep rate and is inversely proportional to the square root of the heat capacity. We demonstrate experimentally and theoretically that this dependence is influenced mainly by the granularity of the superconductor.
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