Some studies on Zr- and Ti-doped multifilamentary Cu-Nb composite wires prepared by in situ techniques

Multifilamentary superconducting wires of Cu 70 Nb 30 and Cu 70 Nb 29 X 1 (where X = Zr and Ti) have been fabricated using the in situ technique. A small decrease in the transition temperature and an increase in both the critical current density and the upper critical field is observed for both dopants. For Zr-doped wires of diameter 0.20 mm, the critical current density is almost independent of field up to 1.5 T, after which there is a sharp drop around μ 0 H c2 . The change in the magnitude and the position of the maximum pinning force have been studied for Zr-doped wires of different diameters.