High field properties of diffusion-processed Nb3(Sn - In) tapes

Upper critical fields and critical currents of diffusion processed Nb3(Sn-In) tapes were measured at 4.2 K as a function of reaction temperature, reaction time, and the concentration of indium in the matrix. These tapes were fabricated with pure niobium steps rather than with indium doped niobium tapes, as was the case reported previously. The highest Hc2achieved with the present samples is 28 T, which is comparable with the best value obtained in the previous samples with indium doped niobium. Above 12T, these samples have higher critical currents than commercial Nb3Sn.