Strongly enhanced current-carrying performance in MgB2 tape conductors by C60 doping

By utilizing C-60 as a viable alternative dopant, we demonstrate a simple and industrially scalable route that yields a 10 similar to 15-fold improvement in the in-high-field current densities of MgB2 tape conductors. For example, a J(c) value higher than 4x10(4) A/cm(2) (4.2 K, 10 T), which exceeds that for NbTi superconductor, can be realized on the C-60 doped MgB2 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 similar to 10 T for C-60 doped MgB2 tapes. A large amount of nanometer-sized precipitates and grain boundaries were found in MgB2 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 MgB2 tapes. (C) 2008 American Institute of Physics.