Superconducting properties of Cu-Nb multi-filamentary composite wires containing Ga as the third element

Abstract

Multi-filamentary superconducting wires of Cu70Nb30 and Cu70Nb29Ga1 have been fabricated by an in situ technique. Doping of Cu70Nb30 with Ga results in a small decrease in the transition temperature Tc. The critical current density Jc, however, increases appreciably. There is also a small increase in the upper critical field Hc2 The pinning force Fp also increases on doping. The maximum (peak) value of Fp is 1.79*104 N cm-2 for an undoped wire of diameter 0.20 mm and 3.18*104 N cm-2 for a doped wire of diameter 0.26 mm.