Degradation and reversibility of I_c due to transversal compressive stress in Ta-reinforced Nb_3Sn superconducting wire

Abstract

Recently, high field superconducting magnet is being desired with improving superconducting wires. On the other hand, a large electromagnetic force is applied to the winding when the magnet is operated, and the characteristic degradation caused by the mechanical stress of the winding cannot be disregarded. In this study, we have investigated the degradation and the reversibility of critical currents (I_c) due to transversal compressive stress at 4.2 K and 14 T. Few works on degradation of superconducting wires against transversal compressive stress have been reported. Ta-reinforced Nb_3Sn superconducoing wire was used as a sample. According to the experimental results, a large recovery of I_c appeared clearly by removing its load after the I_c degradation due to the transversal-compressive force was noticed, and the reversibility was seen.