Long Ag-clad Bi-based superconducting tapes and coils

Abstract

Ag-sheathed Bi-based superconducting single and multifilament tapes have been fabricated using a powder-in-tube technique. A J c of 6,000 A/cm 2 at 77 K over 12 meters of a single core tape is compared with 18,500 A/cm 2 for the tape processed by pressing. A J c of 11,000 A/cm 2 at 77 K and 137,000 A/cm 2 at 4.2 K over 8 meters of a 49 multifilament tape has been achieved. Multiprobe measurements for a tape show that there is no indication of accumulative grain boundary resistance over the entire length at high temperatures. The J c remained unchanged when the tapes were rewound into a pancake coil and a solenoid with an internal diameter of 5 cm for single core tapes and of 1.4 cm for a 49 multifilament tape. Multifilament tapes exhibit robust mechanical properties and feasible for practical applications.