Fabrication and Properties in Ag/Bi2223 Tapes With Ca-Cu-O as Interfilamentary Resistive Barriers

In this study, we fabricated Ag-sheathed Bi2223 tapes with interfilamentary resistive barriers by using standard powder-in-tube (PIT) method and evaluated their AC loss characteristics at 77 K. The mixture of Ca₂CuO₃ and 30 wt.% Bi2212 are used as new barrier materials for tape fabrication. Although some broken parts in barrier layers were observed in a final tape section, it was confirmed that the barriers were almost arranged around each Bi2223 filament. In addition, XRD results indicated that the barrier introduction among the filaments has little side effect for the formation of Bi2223 phase inside the filaments. By introducing the barrier layers, the J_c values at 77 K and self-field are degraded about 15%. From the results of the measurements for AC magnetization loss under parallel transverse field, it was suggested that introducing the mixture of Ca₂CuO₃ and Bi2212 as barriers is effective to increase the transverse resistivity, and also to suppress the electromagnetic coupling among the filaments.