CRITICAL-CURRENT DENSITY ENHANCEMENT IN AG-SHEATHED BI-2223 SUPERCONDUCTING TAPES

A high transport critical current density, J(c), in Ag-sheathed Bi-2223 superconducting tapes has been obtained using the oxide powder-in-tube technique. At 77 K and self-field, the highest J(c) value of 69 000 A/cm(2) was measured for tapes of 80 mu m thickness (I-c=35 A), while the largest critical current, I-c, reached 74 A for tapes of 150 mu m thickness (J(c)=61 000 A/cm(2)). A detailed investigation of the processing parameters has been carried out on the phase content and particle size of the starting powders, and on the sintering treatment and mechanical deformation of the tapes.