TRANSPORT JC(B,T) AND FLUX PINNING BEHAVIOR IN MELT-TEXTURED BI-SR-CA-CU-O HIGH-T(C) SUPERCONDUCTORS

The magnetic field dependence of the transport critical current densities (J(c)) in the temperature range 20-70 K has been measured on melt-textured Bi-Sr-Ca-Cu-O samples. J(c) decreased approximately exponentially with magnetic field. The characteristic magnetic field B*, determined as the magnetic field at which extrapolated J(c)(B) decreased to a certain level, increased slowly with decreasing temperature in the temperature range 70-30 K but a rapid increase below 30 K was observed. F(p)(B, T) and f(p)(b, T) dependences, with f(p) = F(p)/F(p max) and b = B/B*, are presented. A scaling behaviour of f(p)(b, T) similar to that of conventional superconductors was found.