Enhanced flux pinning through a phase formation-decomposition-recovery process in Ag-sheathed Bi(Pb)SrCaCuO wires

A high-critical temperature, T/sub c/, phase formation-decomposition-recovery (PFDR) process has been developed for fabrication of Ag-sheathed (Bi,Pb)/sub 2/Sr/sub 2/Ca/sub 2/Cu/sub 3/O/sub 10+y/ (2223) wires with a short period of melt during the heat treatment. A critical current density, J/sub c/, of 40000 A/cm/sup 2/ at 77 K and 0 T and of 9000 A/cm/sup 2/ at 77 K and 1 T has been achieved. The irreversibility line for the PFDR tape is shifted to much higher temperature than those for normal tape and powder sample for fields up to 6 T. The PFDR processed samples contain a large amount of small spheres of Sr- and Ca-rich phase with a diameter of 1 mu m to 3 mu m, well aligned 2223 grains, highly dispersed, textured 2212 and high concentrations of dislocations (10/sup 10//cm/sup 2/) and stacking faults. The strong coupling between grains is attributed to the interfacial pinning.<
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