Superconducting critical temperature reentrance in F/S/F three-layered structures based on Nb AND Cu41Ni59 alloy

Abstract

Ferromagnet/Superconductor/Ferromagnet (F/S/F) trilayers, in which the establishing of a Fulde-Ferrell Larkin-Ovchinnikov (FFLO) like state leads re-entrance behavior of superconductivity, form the core structure of the superconducting spin valve. The appiarance of pronounced critical temperature oscillations in such trilayers as a function of the ferromagnetic layer thicknesses and the reentrant superconductivity, are the key condition to obtain a large spin valve effect, i.e. a large shift in the critical temperature. Both phenomena have been realized experimentally in the Cu41Ni59/Nb/Cu41Ni59 trilayers, the results of investigation are presented.