LONG MULTIFILAMENT BI-2223 AG-SHEATHED SUPERCONDUCTING TAPES AND SOLENOIDS

Multifilament Ag-sheathed BiPbSrCaCuO (2223) superconducting tapes con taining 49 filaments were fabricated by the powder-in-tube route and t he roll-anneal process. The transport critical current density J(c) wa s 1.3 x 10(4) A cm-2 at 77 K and 7 x 10(4) A cm-2 at 4.2 K in self-fie ld. A 12-m-long tape was used to construct superconducting solenoids ( 50, 28, and 14 mm internal diameters) generating dc fields 380-1070 G at 4.2 K. Measurements of the variation of J(c) with field (0-1.6 T) a nd bend strain (0-5%) are used to explain the performance of the solen oids. The critical bend strain of tapes was about 1.5%.