CHARACTERISTICS OF AG-AU ALLOY SHEATHED BI-PB-SR-CA-CU-O SUPERCONDUCTING TAPES FOR CURRENT LEADS

Oxide superconductor tape with Ag-Au sheath was studied for current le ads. A 100-cm-long current lead of 1000 A with 0.2 W/kA heat leakage w as designed using Ag-11 at. % Au alloy sheath with low thermal conduct ivity. The overall current density of the superconducting tape is requ ired to be 350-770 A/cm2 at 77 K when the superconductor cross-section ratio in the tape is 0.35-0.7. Bi-Pb-Sr-Ca-Cu-0 superconducting tape with Ag-11 at. % Au alloy sheath was fabricated and the critical curre nt density J, was measured. The overall-J(c) was 1700 A/cm2 at 77 K un der 0 T. The possibility of the current lead of 1000 A under 0.28 T wi th 0.2 W/kA was made clear.