Vortex plastic creep in a superconducting crystal of Tl-2223

Abstract

The dissipation in the mixed state of a Tl 2Ba 2Ca 2Cu 3O 10 (Tl-2223) crystal was studied by an analysis of the DC relaxation and that of the frequency dependence of the AC susceptibility. Near the irreversibility line, the field dependence of the activation energy at zero current limit evidences the plastic nature of the vortex movement mediated by individual vortex loops. At lower temperatures, the data are analysed in a current dependent activation energy U( J) framework. The data are analysed in the model proposed by Abulafia et al. in U 0(1−( J/ J 0) 1/2) which predicts a non divergent energy barrier at zero current. The analysis of the magnetic field dependence of U 0 has shown that the plastic model used in the region of the irreversibility line can account for the observations. In this system, no elastic collective creep was observed in the domain that we have explored.