Effect of the Mo addition on the superconducting transition temperature Tc of A15 Nb3Al

The effect of the Mo addition on the superconducting transition temperature, T-c, of the A15 Nb3Al alloy has been investigated on the basis of a general trend that T-c increases as the lattice parameter decreases for this kind of alloy series. The lattice parameter of the A15 phase decreases monotonically with increasing Mo content. T-c of the Nb-20 mol% alloys in addition of 2 to 3.5 mol%Mo becomes higher than that of the Mo-free alloy, T-c(0), and attains a peak of 14.8 K at 2 mol%Mo, which is about 2 K higher than T-c(0). For Mo contents higher than 5 mol%, the enhancing effect of Mo on the T-c of Nb3Al alloy disappears.