YBA2CU2O2 LOW-LOSS CURRENT LEADS

The low thermal conductivity of High Temperature Superconducting ceram ic YBCO(<1Wm(-1)K(-1) at 77K) in comparison with normal metal such as copper (similar to 480 Wm(-1)K(-1) at 77K) suggests their use as curre nt leads. We demonstrate a modular lead design which has very low resi stance contacts and where the power dissipated at an arbitrarily chose n current level of 100A is several orders of magnitude lower than that dissipated by the normal metal leads presently used in such applicati ons. This suggests that significant cost savings may be made resulting from the reduced liquid helium boil-off rate. The leads are fabricate d by novel ceramic processing techniques which give a high degree of u niformity and reproducibility, and strengths in flexure approaching 20 0MPa for the individual elements, the highest values reported.