On the dissipation mechanism in polycrystalline Ba2YCu3O7-δ superconductor

Modified Ambegaokar-Halperin model has been applied to the temperature dependent resistivity (R-T) curves of polycrystalline Ba2YCu3O7-delta superconductor. The curves, drawn using the modified AH model, fit well with the experimental R-T data points for different magnetic fields ranging from 0 to similar to0.5 T. Each curve is found to possess two distinct regions, which suggests the dissipation phenomena in Ba2YCu3O7-delta Superconductor is caused by two mechanisms, viz. the order parameter fluctuations and the vortex-dynamics. A new dissipation transition temperature T-BP has been observed, across which one dissipation mechanism possibly changes over to another. On either side of T-BP there exists a small region where both the mechanisms seem to operate. (C) 2004 Elsevier B.V. All rights reserved.