Transport in Ferromagnet/Superconductor spin valves

TL;DR

This paper investigates charge transport, spin current, and spin transfer torque in realistic ferromagnet/superconductor spin valves with layered structures, considering interface scattering and various parameters, providing comprehensive insights into device behavior.

Contribution

It presents a fully self-consistent calculation of conductance, spin current, and torque in F/N/F/S spin valves, including interface effects and a range of realistic parameters, which was not comprehensively addressed before.

Findings

Conductance varies with bias voltage and magnetization angle.

Interface scattering significantly affects transport properties.

Spin transfer torque depends on device parameters and magnetization configuration.

Abstract

We consider charge transport properties in realistic, fabricable, Ferromagnet/Superconductor spin valves having a layered structure $F_1/N/F_2/S$, where $F_1$ and $F_2$ denote the ferromagnets, $S$ the superconductor, and $N$ the normal metal spacer usually inserted in actual devices. Our calculation is fully self-consistent, as required to ensure that conservation laws are satisfied. We include the effects of scattering at all the interfaces. We obtain results for the device conductance $G$, as a function of bias voltage, for all values of the angle $\phi$ between the magnetizations of the $F_1$ and $F_2$ layers and a range of realistic values for the material and geometrical parameters in the sample. We discuss, in the context of our results for $G$, the relative influence of all parameters on the spin valve properties. We study also the spin current and the corresponding spin transfer torque in $F_1/F_2/S$ structures.