Observation of the “Inverse” spin valve effect in a Ni/V/Ni trilayer system

An experimental study of magnetic and superconducting properties of a trilayer Ni/V/Ni thin film system grown on single-crystalline MgO(001) substrate is reported. The field dependence of the superconducting transition temperature T c for samples comprising Ni layers with similar values of the coercive field H c reveals no anomalies. However, in samples with different thicknesses of the nickel layers the difference in H c amounts up to ΔH c ∼ 1.8 kOe, thus enabling to manipulate the relative orientations of the layers’ magnetization by an external magnetic field. Surprisingly, for these samples the T c for the parallel orientation of the magnetizations of the Ni layers is higher, in a certain magnetic field range, than for the antiparallel one, at odds with theoretical predictions. Possible reasons of this contradiction are discussed.