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The European Physical Journal B
ISSN: 1434-6028 (printed version)
ISSN: 1434-6036 (electronic version)
Abstract Volume 2 Issue 3 (1998) pp 283-292
Effect of changing microstructure of Y-Ba-Cu-O superconductors on the vortex motion under non-equilibrium thermal conditions
I. Kirschner (1) (a), R. Laiho (2), A.C. Bódi (3), E. Lähderanta (2), M. Marosvölgyi (4)
(1) Department for Low Temperature Physics, Eötvös University, 1088 Budapest, Hungary
(2) Wihuri Physical Laboratory, University of Turku, 20014 Turku, Finland
(3) Institute of Experimental Physics, Kossuth University, 4001 Debrecen, Hungary
(4) Department of Physics and Astronomy, University of Leiden, 2300 RA, Leiden, The Nederlands
Received: 17 December 1997 / Accepted: 28 January 1998
Abstract: Repetition of cooling and heating of high-Tc superconductors is detected to be able to result in some change of their microstructure. A non-equilibrium experimental technique provides direct measurement of the velocity of vortex motion in high-Tc Y-Ba-Cu-O superconductors. Its value falls in the interval of $8.3 \times 10^{-2}- 16.0 \times 10^{-2}$ mm/s depending on the number of the cooling or heating cycles, to which the samples are submitted. The thermal cycling created homogenization of the specimen's microstructure, and is presumed to cause this phenomenon, decreasing the number and strength of pinning centers. This supposition is proved by X-ray diffractography and transmission electron microscopy. A simple irreversible thermodynamic theory is elaborated to describe the reason, direction and dissipative character of the vortex motion.
PACS. 74.25.-q General properties; correlations between physical properties in normal and superconducting states - 74.40.+k Fluctuations (noise, chaos, nonequilibrium superconductivity, localization, etc.) - 74.60.Ge Flux pinning, flux creep, and flux-line lattice dynamics
(a) Fax: 36-1-2660206.
Online publication: May 27, 1998
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