Negative differential resistance and other features of spin-dependent electron transport in double-barrier hybrid superconductor-ferromagnetic metal-normal metal structures

Spin-dependent electronic transport is theoretically investigated for double-barrier hybrid structures S-IF-F-IF-N and S-IF-N-IF-N, where S is a superconductor; F and N are ferromagnetic and normal metals, respectively; and IF is the spin-active barrier. It is shown that in the case of strong superconducting proximity effect and sufficiently thin F layers, the differential resistance of such structures can become negative at some voltages, and the voltage dependence of the current can have an N-shaped form. Characteristic feature of the differential resistance is its asymmetric dependence on voltage, which is most clearly manifested at strong polarization of at least one of the barriers. The influence of impurity spin-orbit scattering processes in the N-layer located between the barriers is investigated. The study was carried out for the case of diffusion electron transport.