Fabrication and properties of long Bi2223 Ag-sheathed superconducting tapes

Long length Ag-sheathed Bi-based superconducting single and multifilamentary tapes up to 43 meters have been fabricated using powder-in-tube technique. A Ic up to 15 A and Jc of 7,500 A/cm2 at 77 K over the entire length has been achieved. For short multifilament tapes, a Jc of 17,200 A/cm2 at 77 K and 140,000 A/cm2 at 4 K has been achieved in zero field and weak links are improved. Multiprobe measurements for a tape show that the Jc is rather uniform along the length of the tapes with a variation of 10%. There is no indication of accumulative grain boundary resistance effect over the entire length at high temperatures. The critical strains for bend tests show a dependence on the tape thickness, the number of filaments and Ag/oxide volume ratio, attributable to the improved strength and flexibility of the special interfacial layer between Ag and oxides formed during the thermomechanical processes