High critical current densities in Nb_3Sn films with engineered microstructures - artificial pinning microstructures

摘要

Films with layers of Nb, Cu, and Sn have been fabricated to simulate a Nb_3Sn bronze-type process. These Nb_3Sn films have produced critical current densities greater than 1 x 10~6 A/cm~2 at 4.2 K and 7.5 T. Niobium films doped with Y, Sc, Dy, Al_2O_3, and Ti have been deposited with e-beam co-evaporation onto 75 mm diameter Si wafers with a 100 nm SiO_2 buffer layer. The Nb layer was followed by a layer of Cu and a layer of Sn to complete the bronze-type process. The films with the highest J_c had about 8 vol.