Critical current densities and magnetic hysteresis losses in submicron filament bronze-processed Sb,Sn wires

This paper reports on submicron filament bronze-processed multifilamentary Nb3Sn wires with Cu-5at%Sn matrix and Nb or Nb alloy cores. The Nb alloy cores contained each of 1at%Zr, Ti, Hf or Ta. Among the peripheral Cu stabilizer type wires, the Nb-1Ta core wire showed the highest non Cu area critical current density Jc of 3 x 104 A/cm2 at 12 T after an optimum heat treatment, in spite of its relatively low Sn concentration in the matrix. The deformation of Nb cores into ribbon like shapes was apparently suppressed by the 1 at% addition of Ti, Hf or Ta. The values of Jc per unit magnetic hysteresis loss for the Ti, Hf and Ta alloyed Nb core wires have been evaluated to be higher than that for the pure Nb core wire