Low-field irreversibility line and its anisotropy of textured (Bi,Pb)2Sr2Ca2Cu3Oy silver-clad tapes

Abstract

The irreversibility line Hirr(T) of textured (Bi,Pb)2Sr2Ca2Cu3Oy, silver-clad tapes was obtained by ac susceptibility (ACS) and magnetoresistivity (MR) below 1500 G. It is found that, in the framework of flux motion, the Hirr(T) is determined by the thermally activated flux flow (TAFF) rather than the so-called giant flux creep, and the experimentally obtained Hirr(T) line is related to a certain resistivity criterion in both ACS and resistivity measurements. Hirr(T) is found to be significantly depressed by the amplitude of applied driving AC field and generally lower than that measured from the resistivity. The anisotropy in Hirr(T) is found to follow a scaling behaviour as described by the anisotropic effective mass model. © 1999 Published by Elsevier Science B.V. All rights reserved.