Resistive Transitions in Nb/Cu0.41Ni0.59/Nb Trilayers

The superconducting phase transition in Nb/Cu0.41Ni0.59/Nb trilayers, with superconducting (S) Nb and ferromagnetic (F) Cu0.41Ni0.59, has been experimentally studied as a function of the F-layer thickness by measuring the temperature dependence of the electrical resistance R (T). It is shown that the shape and the width of the R (T) curves depends on the Cu0.41Ni0.59 thickness, in particular in the regime where pi is the coupling between the S layers, which can be expected. To explain the data, we developed a qualitative model which makes the interconnection between the superconducting phase transition and the 0 to pi transition in SFS structures are more evident.