Effects of Cu and Ga additions to Nb3Sn superconductors prepared by infiltration process

The effects of Cu and Ga additions on the superconducting properties of infiltration-processed Nb3Sn have been studied. The addition of Cu to the Sn improves the overall critical current density J/sub c/ at entire fields, which is considered to result from the enhancement in Nb3Sn growth rate. J/sub c/ of 8 x 104 A/cm2 at 4.2 K and 12 T has been obtained for the specimen infiltrated with Sn-20at%Cu alloy. The Ga addition has been found to improve J/sub c/ at high magnetic fields, which is probably a consequence of an increase in the upper critical field H/sub c2/. However, at lower fields J/sub c/ is somewhat lower than that of the specimens without Ga