Improvements of current-carrying capacities of the composite-processed Nb3Sn in high magnetic fields

The Nb3Sn growth rate Hc2 and Jc in high fields (⩾12 T) of composite-processed Nb3Sn are greatly increased by the addition of hafnium to the niobium core. Furthermore, the simultaneous addition of hafnium to the core and gallium to the matrix more significantly enhances Hc2, and Jc in high fields. Jc of the Nb-Hf/Cu-Sn-Ga wire specimens exceeds 1×105 A/cm2 at 17 T, suggesting the possibility of fabricating multifilamentary Nb3Sn composite wires that stand use in fields at least up to 17 T.