Neutron-irradiation effects in the pseudobinary compound Nb3(SnGa): Changes in Tc, Ic, and flux pinning

Specimens of single-core wires of Nb3(SnGa) have been neutron irradiated at C to fluences of 2.6 × 10¹⁹n/cm²(E>1.0 MeV). Measurements of Icat 4.2 K in transverse magnetic fields to 22 T, and measurements of Tcwere made. The interest in this material (∼ 1 at.%Ga in the Nb3Sn layer made by the "bronze process") stems from the greater critical-properties\´ values (Tc=17.4K, T) relative to those of Nb3Sn. Results are given for two different specimen reaction temperatures, 700 and 750°C. Increases in Icfor low-fluence (<3 × 10¹⁸n/cm²) irradiations similar to those observed for Nb3Sn were observed, but with greater relative increases for the specimens (750°C) that had the lower initial current density. Decreases in Icat higher fluences scaled with the measured decreases in Tcsimilar to behavior of Nb3Sn. Increases in Hc2of the lower-temperature-reacted specimens were much smaller than those observed in Nb3Sn. In the higher-temperature-reacted specimens, the lack of any Hc2increases at all suggests that some kind of limiting mechanism is active. For neutron fluences above n/cm²the limiting of Hc2is not in evidence.