Strongly enhanced current-carrying performance in MgB_2 tape conductors by C_(60) doping

摘要

By utilizing C_(60) as a viable alternative dopant, we demonstrate a simple and industrially scalable route that yields a 10～ 15-fold improvement in the in-high-field current densities of MgB_2 tape conductors. For example, a J_c value higher than 4 × 10~4 A/cm_2 (4.2 K, 10 T), which exceeds that for NbTi superconductor, can be realized on the C_(60) doped MgB_2 tapes. It is worth noting that this value is even higher than that fabricated using strict high energy ball milling technique under Ar atmosphere. At 20 K, H_(irr) was ～10 T for C_(60) doped MgB_2 tapes. A large amount of nanometer-sized precipitates and grain boundaries were found in MgB_2 matrix. The special physical and chemical characteristics of C_(60), in addition to its C containing intrinsic essence, are a key point in enhancing the superconducting performance of MgB_2 tapes