Superconducting and magnetic properties of Nb/Pd1-xFex/Nb triple layers

The superconducting and magnetic properties of Nb/Pd1-xFex/Nb triple layers with constant Nb layer thickness d(Nb) = 200 Angstrom and different interl ayer thicknesses 3 Angstrom less than or equal to d(PdFe) less than or equa l to 80 Angstrom are investigated. The thickness dependence of the magnetiz ation and of time superconducting transition temperature shows that for sma ll iron concentration x the Pd1-xFex layer is likely to be in the paramagne tic state for very thin films whereas ferromagnetic order is established fo r x greater than or equal to 0.13. The parallel critical field B-c2 paralle l to (T) exhibits a transition from two-dimensional (2D) behavior where the Nb films are coupled across the interlayer, towards a 2D behavior of decou pled Nb films with increasing dPdFe and/or x. This transition allows a dete rmination of the penetration depth xi(F) of Cooper pairs into the Pd1-xFex layer as a function of x. For samples with a ferromagnetic interlayer xi(F) is found to be independent of x.