The Critical Properties of Three A15 Multi-Filamentary Superconductors Changed by Axial Compression and Tension

Abstract

Three different types of A15 conductors (Nb3Sn, Nb3A1 and V3Si) are investigated on the axial strain dependence of the critical parameters. The critical current of these conductors is investigated over a broad range from −1 to +0.5% axial strain in the A15 filaments. The strain dependence of the (extrapolated) upper-critical field is evaluated with Ekin’s power-law description for the axial strain and a description that is based on the deviatoric strain tensor. The formulation based on the deviatoric strain incorporates the entire strain tensor in the deformation dependence of the critical properties. The critical current scaling in a V3Si sample in the compressive strain regime is investigated and correlates well with a linear dependence of the upper-critical field on the deviatoric strain. A comparison is presented for the dependence of the upper-critical field in three A15 conductors. Finally the T c of a Nb3Sn conductor is investigated in a wide strain regime from compressive to tensile strain.