Current transfer in multifilamentary superconductors. II. Experimental results

Abstract

Measurements are reported of the current‐transfer effect in a 0.58×0.68‐mm NbTi (180 filament) copper‐matrix wire, and in a 0.33×0.66‐mm Nb₃Sn (3553 filament) bronze‐matrix wire at magnetic fields from 2 to 8 T. With a voltage sensitivity of 100 nV, the effect of current transfer in the copper : NbTi wire was too small to be measured at a distance 1 cm from the current contact. In the bronze : Nb₃Sn wire, however, the effect was relatively large and resulted in voltage‐current characteristics which had an extensive linear region. The slope of the linear region decreased with distance x from the current contact as x^−2±0.3 and reached a value of 10⁻¹² Ω cm, for example, at a distance of 3±0.5 cm. Both the magnitude and functional dependence of the measured current‐transfer effects correspond closely to that predicted by theory.