SOME STUDIES ON ZR-DOPED AND TI-DOPED MULTIFILAMENTARY CU-NB COMPOSITE WIRES PREPARED BY IN-SITU TECHNIQUES

Multifilamentary superconducting wires of CU70Nb30 and CU(70)Nb(29)X(1 ) (where X = Zr and Ti) have been fabricated using the in situ techniq ue. A small decrease in the transition temperature and an increase in both the critical current density and the upper critical field is obse rved for both dopants. For Zr-doped wires of diameter 0.20 mm, the cri tical current density is almost independent of field up to 1.5 T, afte r which there is a sharp drop around mu(o)H(c2). The change in the mag nitude and the position of the maximum pinning force have been studied for Zr-doped wires of different diameters.