ROBUST SUPERCONDUCTING TAPES BASED ON BI2SR2CA2CU3O10-DELTA

A rugged conductor based on the Bi2Sr2Ca2Cu3O10-delta has been developed by dispersing Ag throughout the matrix on a micrometer scale. The Ag seems to effectively blunt crack tips and provides regions for plastic flow. The performance degrades relatively little with the strains of handling, soldering and quenching to 77 K. Tapes having a critical current density of 4,500 A/cm2 at 77 K and zero field will show over 20 000 A/cm2 at 4.2 K and zero field. At 20 T for the field perpendicular to the tape surface, these conductors show 2 800 A/cm2 at 4.2 K and 2 200 A/cm2 at 20 K. The critical current density falls roughly linearly with strain and decreases from about 22 000 A/cm2 at zero strain to about 10 000 A/cm2 at 1.0% bending strain.