Effect of the variation of the exchange energy on the superconducting critical temperature of S/F/S trilayers

The effect of the exchange energy variation in weakly ferromagnetic alloys on the superconducting resistive transition of superconductor/ferromagnet/superconductor (S/F/S) trilayers is studied. Critical temperature, T <Subscript> c </Subscript>, and resistive transitions versus the F-layer thickness, d <Subscript> F </Subscript>, have been analyzed in Nb/Cu<Subscript>0.41</Subscript>Ni<Subscript>0.59</Subscript>/Nb and Nb/Pd<Subscript>0.81</Subscript>Ni<Subscript>0.19</Subscript>/Nb trilayers. We show that T <Subscript> c </Subscript>(d <Subscript> F </Subscript>) dependence is sensitive to magnetic inhomogeneities in the F-layer for values of d <Subscript> F </Subscript> corresponding to thickness range where the π-superconducting state is established. Copyright EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg 2011