Fluctuation theorem for spin transport at insulating ferromagnetic junctions

TL;DR

This paper derives general nonequilibrium relations for spin transport at magnetic junctions, revealing extended Onsager relations and providing insights into unidirectional spin Hall magnetoresistance in insulating ferromagnetic systems.

Contribution

It introduces a quantum fluctuation theorem-based framework for understanding spin transport and noise relations in magnetic junctions, extending Onsager relations to nonequilibrium conditions.

Findings

Extended Onsager relations between spin conductance and noise.

Unified understanding of spin Hall magnetoresistance.

Framework applicable to general spin transport setups.

Abstract

General relations for nonequilibrium spin transport at a magnetic junction between a normal metal and a ferromagnetic insulator are derived from the quantum fluctuation theorem. They include the extended Onsager relations between the spin conductance and the spin-current noise that hold for nonequilibrium states driven by an external current. These relations, that are valid for a general setup of spin Hall magnetoresistance, provide a comprehensive viewpoint for understanding of unidirectional spin Hall magnetoresistance in insulating ferromagnetic junctions.