Dimensional crossover in superconductor/spin-glass multilayers

Abstract

We have prepared epitaxial superconductor/spin-glass multilayers, V/AgFe. The spin-glass layers were made by coevaporation of Ag and Fe resulting in a AgFe system having 1 atomic%Fe. We measured critical temperatures and critical fields for multilayers with constant V thickness TV=14 nm and 35 nm, and varying AgFe thickness 1–8 nm. The critical fields as a function of temperature and angle show that a AgFe thickness of 4 nm is able to decouple the V layers in the films with tV-14 nm. The decoupling is not observed in in the multilayers with tV=35 nm, which have a higher Tc. This suggests that decoupling of the V layers occurs only when Tc becomes smaller than the spinglass temperature.