Recent Progress in BPSCCO Wire Fabrication and Application Prototypes

Abstract

A Jc (77 K) of a 1,200 m long silver-sheathed bismuth-based wire has reached 10,000 A/cm², as evaluated with a strict Ic criterion of 10^-14Ω • m for overall wire cross-sectional area. One of the most important issues for Jc enhancement is grain connectability. Differential technique of ZFC (zero field cooling) curves proved to be a simple and effective evaluation method for grain connection. The performance of application prototypes progressed greatly. Three typical examples were as follows; 1) Current leads of 2,000 A carrying capability have been implemented to NbTi bending magnets of superconducting synchrotron radiation facility of Sumitomo Electric, and have been stably operated for over one year from December 1993. 2) Two flexible cable conductors of 1m-length, having Ic (77 K) of 5,800 A (Jc=12,000 A/cm²) and 12,000 A (Jc=11,000 A/cm²), were fabricated with multilayer wound technique. 3)A 60 mm bore magnet, cooled with GM refrigerator down to 21 K, has stably generated 3 T without any cryogen. The size of this magnet was large enough for actual applications.