https://doi.org/10.1007/s100510050251
Effect of changing microstructure of Y-Ba-Cu-O superconductors on the vortex motion under non-equilibrium thermal conditions
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
Published online: 15 April 1998
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
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
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 1998
