Controlling Exchange Coupling Strength in NixCu1−x Thin Films

The thickness (dF) and concentration (x) dependence of the Curie temperature of NixCu1−x (dF) ferromagnetic alloy layers (x=0.55, 0.65, dF=[4.5 nm÷12 nm]) in contact with a vanadium layer was studied. The Curie temperature of the ferromagnetic layers depends on the thickness when it is comparable with the transition layer between the F and the vanadium layers, which is attributed to the proximity coupling of the interface region with the rest of the F layer. The present study provides valuable information for fabrication of samples with controlled exchange coupling strength for studies of superconductor/ferromagnet proximity effects.