Magnetization analysis of sintered Bi2223 using an extended critical state model

Abstract

The field dependence of the magnetization was measured for sintered Bi2223 high Tc superconductor under a field amplitude of 5 T from 10 to 90 K. These data were analysed using our critical state model involving an equilibrium magnetization Meq and exponential decay of Jc. Some magnetic parameters including the equilibrium critical current density were determined for the intra-grain and inter-grain parts. The temperature dependences of the intra-grain and inter-grain Jc were also discussed. It was revealed that single vortex pinning was dominant in the intra-grain part, and flux creep caused by collective pinning was confirmed in the inter-grain part.