The Fe influence on the vortex response to the AC field in bulk (Bi,Pb): 2223 superconductor

摘要

The effect of Fe3+ ions on the inter- and intragranular Tp and Tg temperatures of the imaginary peaks of the AC susceptibility has been studied for a (Bi, Pb):2223 superconductor. The linear dependencies of T-p and T-g as a function of AC field amplitude agree with Muller critical state model. The Fe3+ ions induced a fast decrease of inter and intragranular pinning force densities. The intergrain critical current density J(cj) calculated from X"(T) curve is lower in x = 0.02 Fe doped sample than in x = 0.09 sample. J(cj)(T) dependence near T-c agrees with the assumption of SNS intergrain junctions. [References: 15]