A thermally driven spin-transfer-torque system far from equilibrium: enhancement of the thermoelectric current via pumping current

TL;DR

This paper models a small ferromagnet under thermal and magnetic influences, deriving equations that reveal a regime where precession enhances thermoelectric current via pumping effects.

Contribution

It introduces a self-consistent quasi-classical model for thermally driven spin-transfer torque systems, including a novel regime with persistent precessions that boost thermoelectric current.

Findings

Identification of a persistent precession regime.

Enhanced thermoelectric current due to pumping.

Derivation of modified Landau-Lifshitz-Gilbert equations.

Abstract

We consider a small itinerant ferromagnet exposed to an external magnetic field and strongly driven by a thermally induced spin current. For this model, we derive the quasi-classical equations of motion for the magnetization where the effects of a dynamical non-equilibrium distribution function are taken into account self-consistently. We obtain the Landau-Lifshitz-Gilbert equation supplemented by a spin-transfer torque term of Slonczewski form. We identify a regime of persistent precessions in which we find an enhancement of the thermoelectric current by the pumping current.