Spin Torque and its Relation to Spin Filtering

TL;DR

This paper explores how spin transmission resonance can disrupt spin filtering in ferromagnetic films, affecting spin torque transfer, with implications for spintronic device design.

Contribution

It identifies conditions under which spin transmission resonance causes ferromagnetic films to become transparent, challenging traditional understanding of spin filtering effects.

Findings

STR causes failure of spin filtering

Ferromagnetic film becomes transparent at STR

Spin torque transfer is suppressed at STR

Abstract

The spin torque exerted on a magnetic moment is a reaction to spin filtering when spin-polarized electrons interact with a thin ferromagnetic film. We show that, for certain conditions, a spin transmission resonance (STR) gives rise to a failure of spin filtering. As a consequence, no spin is transfered to the ferromagnet. The condition for STR depends on the incoming energy of electrons and the thickness of the film. For a simple model we find that when the STR condition is satisfied, the ferromagnetic film is transparent to the incoming electrons.