Theory of spin-coherent transport through a defect spin state in a metal/ferromagnet tunnel junction during ferromagnetic resonance

TL;DR

This paper presents a theoretical framework for understanding how a defect spin interacts coherently with a ferromagnet during ferromagnetic resonance, affecting charge transport and enabling defect identification.

Contribution

It introduces a novel theory describing spin-coherent transport through defect states in ferromagnet junctions during resonance conditions.

Findings

The defect spin influences charge current via local effective fields.

Dynamic spin accumulation occurs due to spin filtering by the ferromagnet.

The model allows for defect environment characterization through current measurements.

Abstract

We describe the coherent interaction between a defect spin at the interface of a ferromagnet and a non-magnetic material, under bias and when the magnetization of the ferromagnetic contact precesses during ferromagnetic resonance. The magnet filters charge carriers by preferentially allowing in parallel spins, which leads to a dynamic spin accumulation on the defect. Local effective fields acting on the defect spin site modify the defect spin's precession, which also modifies the charge current through the defect. This new form of current-detected spin resonance reveals the local environment of the defect, and thus can yield the defect identity.