Recent R and D progress on DI-BSCCO wires with high critical current properties

Sumitomo Electric has been developing the silver-sheathed Bi2223 multi-filamentary wires since the discovery of Bi-based superconductors. DI-BSCCO is the high performance wires produced with the controlled-overpressure (CT-OP) sintering technique. The present commercial DI-BSCCO can provide the uniform high critical current, Ic, up to 180 A over 2000 m, and recently 200 A were succeeded to obtain with the same kind of 1000 m-long wires, resulting from the improvement and control of the microstructure in Bi2223 multi-filaments. The short trial wires of several meter have exhibited over 240 A as the highest Ic at 77 K, self-field (corresponding to 580 A per 1 cm-width) according with high Tc over 112 K. Besides, the optimization of carrier density after CT-OP led to further enhancement of Ic, reaching 250 A. All the derivative products have also uniform critical current property over the entire length even after lamination with the reinforcements. The performances of DI-BSCCO can meet the growing needs for various high temperature superconducting applications involving high in-field properties, such as magnets and motors. The recent progress on Ic including in-field properties along with the remarkable findings on the performances of DI-BSCCO will be shown.