Distribution of<i>T</i>_cfrom calorimetry and the determination of Sn gradients in bronze route Nb₃Sn wires with an internal and external Ti source

Abstract

We have investigated the influence of two different Ti doping methods on the superconducting properties of bronze route Nb3Sn multifilamentary wires. The first doping method introduces NbTi rods into NbTa filaments embedded in a Cu15.4Sn bronze matrix ('internal' Ti). The second method uses Cu15.5Sn0.25Ti bronze as an external source of Ti ('external' Ti). The wires prepared by 'external' Ti doping were found to exhibit the highest critical current values although the conductor configurations were identical.