Critical fields of Nb-Ta multilayers

Abstract

Nb-Ta multilayered films prepared by magnetron sputtering have been studied by critical-field measurements. We have examined the effects of substrate orientation and deposition temperature on the properties of the films. Three-dimensional to two-dimensional crossover is observed. For films with larger Nb layer thicknesses an additional transition in $H_{c2?}$ at lower temperatures is observed which cannot be accounted for by the interfacial regions.