MAGNETIC-PROPERTIES IN ALIGNED (TL0.5PB0.5)SR2CA2CU3O9 HIGH-T-C SUPERCONDUCTOR

The magnetic properties of c-axis-oriented powders of (Tl0.5Pb0.5)Sr2C a2Cu3O9 have been investigated. With increasing field, the anisotropy of the persistent critical current density J(p) decreases and crossove r occurs at higher field. The sense of the anisotropy reverses. Theref ore, the flux motion is easier for H parallel to e than for H parallel to ab at higher held. The pinning forces show the scaling behavior of h(0.8)(1 - h)(2.0) and are maximum at h = 0.29, Near T-c, the slope d H(c2)/dT of the upper critical field is -2.1T/K for fields parallel to the c axis.