MAGNETIZATION STUDIES AND IRREVERSIBILITY BEHAVIOR OF HIGH-T-C SUPERCONDUCTING BI(PB)-2223 MULTIFILAMENTARY AG-SHEATHED PIT TAPES PREPARED FROM DIFFERENTLY SYNTHESIZED PRECURSOR POWDERS

Magnetization measurements performed at 5 K and irreversibility behavi or of (Bi, Pb)(2)Sr2Ca2Cu3O10+x (or (Bi(Pb)-2223) multifilamentary (MF ) Ag-sheathed tapes under H parallel to c over a temperature range fro m 5 to 77 K have been investigated for short samples cut from fully pr ocessed longer length tapes. The sample containing the precursor powde r prepared from the method of solution route (spray-pyrolysis) showed an enhancement in irreversibility behavior over those with precursor p owders prepared by solid-state reaction means (two powder route and dr y mixing). All MF Bi(Pb)-2223 samples exhibited an exponential magneti c critical current density dependence beyond 1 T field at 5 K with H p arallel to c, which is typical of flux creep. The field dependence of irreversibility temperature obtained from field-cooled and zero field- cooled magnetization curves for intermediate-rolled and -pressed uni-a xially monocore and MF Bi(Pb)-2223 Ag-cladded tapes have also been inv estigated. Improvement in core pinning from irreversibility behavior o f monocore tapes compared with the MF samples can be attributed to bet ter microstructure and grain orientation. (C) 1998 Published by Elsevi er Science Ltd.