Upper critical field anisotropy in Nb-Ti tapes

Nb47Ti tapes were prepared with various degrees of rolling and round-wire d rawing after the final heat treatment, Roiling aligned the precipitates and produced 2D behavior in several tapes, as indicated by the development of anisotropy of the upper critical field Hc2- The anisotropy was observed pri or to the onset of strong proximity coupling, as indicated by the change of the critical temperature T, These different dependencies resulted in one t ape having a 9.5 K T-c and a 12.3 T H-c2 at 4.2 K in parallel field. Since the 2D behavior occurred prior to the optimization of flux pinning with inc reasing strain, the implications of 2D properties on the pinning force are discussed.