High field j/sub c/ and scaling behavior in Nb-Ti and alloyed Nb-Ti superconductors

Careful measurements of the J/sub c/ of four commercial NbTi and alloyed NbTi composites have been made between 4.2 and 2K at fields up to H/sub c2/. It is shown that the pinning curves for the four composites are rather similar and all scale with temperature. The high accuracy scaling behavior should be useful to magnet designers. These scaling relations have been applied to the predictions of J/sub c/ in the alloy Nb43w/oTi 25w/oTa, where the H/sub c2/ at 2K is about 1.25T higher than with nb46.5w/oTi. The NbTiTa alloy is seen to have a temperature margin of 0.75K over the nb46.5w/oTi alloy and the predicted J/sub c/ values of 600-800 A/mm/sup 2/ (12T/2K) exceed those of filamentary Nb/sub 3/Sn. 15 refs