Effect of an inhomogeneous exchange field on the proximity effect in disordered superconductor-ferromagnet hybrid structures

Abstract

We investigate the effect of an inhomogeneous exchange field on the proximity effect in superconductor-ferromagnet hybrid structures within the quasiclassical theory of superconductivity. As an example, we study a superconductor-ferromagnet bilayer with an in-plane spiral magnetic order in the ferromagnet. The superconducting proximity effect induces in this case triplet correlations in the bilayer that are sensitive to the local quantization axis of the exchange field in the ferromagnet. The coexistence of singlet and triplet pair correlations in the bilayer results into a sensitivity of the superconducting transition temperature on the spatial variation of the exchange field in the ferromagnetic layer. We show that the inhomogeneity also tends to suppress the oscillating behavior of the pair amplitudes in the ferromagnet.