STRENGTH AND CRITICAL CURRENT-DENSITY OF BI(PB)-SR-CA-CU-O AND Y-BA-CU-O IN SILVER-SHEATHED SUPERCONDUCTING TAPES

The critical current density at 77 K at 0 T and the tensile strength at room temperature of high T(c) Bi(Pb)-Sr-Ca-Cu-O and Y-Ba-Cu-O oxides in silver-sheathed tapes prepared by the powder-in-tube method were investigated. The main results can be summarized as follows. (1) The critical current density and the strength of both oxides increased with decreasing thickness. (2) The strength of the Bi(Pb)-Sr-Ca-Cu-O oxide was 120 MPa at most, being comparable to that of the Y-Ba-Cu-O oxide, but far lower than that of Nb3Sn compound. (3) When the oxides were weak, the higher the strength, the higher was the current density in both Y-Ba-Cu-O and Bi(Pb)-Sr-Ca-Cu-O tapes. The textured structure in the Bi(Pb)-Sr-Ca-Cu-O tape with thin oxide raised current density effectively, while it raised the strength only slightly.