Superconducting properties of V3Ga composite wires

Studies of the superconducting properties of V3Ga single filament composite wires grown by solid state reaction are presented. The three alloy compositions investigated were: V/Cu-15.4 at.% Ga, V-6.1 at.% Ga/Cu- 15.4 at.% Ga and V-9.0 at.% Ga/Cu-17.5 at.% Ga. Critical currents were measured at 4.2K in transverse magnetic fields to 175kG and transition temperature data were obtained by ac mutual inductance techniques for V3Ga formed at temperatures from 525°C-700°C. Growth rates for V3Ga were strongly influenced by alloy composition and formation temperature with more rapid growth occurring in composite wires with higher Ga contents. In addition to the more rapid growth rates obtained, a factor of 10 improvement in the critical current density (Jc) also was exhibited in V3Ga grown at 600°C in the V- 9.0 at.%/Cu-17.5 at.% Ga composite specimen. The best Jcobserved to date was 10⁶A/cm²in a transverse magnetic field of 100kG for a wire reacted at 550°C.