Influence of thickness on parallel and perpendicular field dependences of Jc of NbTi films

Abstract

The critical current density, J c, of NbTi films has been measured in both parallel and perpendicular fields at 4.2 K, while varying the film thickness from 26 to 500 nm. It was observed that the strength of a certain cross field, B *, where J c in perpendicular fields exceeds that in parallel fields, decreases as film thickness increases. On the basis of analyses of scaling parameters, the scaling law of the pinning force density with NbTi film thickness as a parameter in both parallel fields and perpendicular fields is discussed through comparison with that of NbTi–Cu multilayer films.