CHARACTERIZATION OF BI-PB-SR-CA-CU-O RODS SUBJECT TO DIRECT-CURRENT ZONING (DCZ) AND DIRECT-CURRENT ANNEALING (DCA)

Bulk samples with a nominal Composition of Bi1.6Pb0.4Sr2Ca3Cu4O12 were prepared as rods by a melt casting process. A dc field was applied to these rods and this produced a well-defined hot zone which travelled along the rod from positive to negative and disappeared at the negativ e end (DCZ). A further zone could be initiated at the positive electro de by a small increase in the applied field. Direct current zoned rods were then uniformly heated by applying a field just below that requir ed to produce a zone (DCA) and resulted in the production of an 80K su perconducting phase. The rods were characterised by means of microstru ctural and physical property studies.