Magnetization damping in noncollinear spin valves with antiferromagnetic interlayer couplings

TL;DR

This paper investigates how noncollinear magnetic configurations in synthetic antiferromagnetic spin valves influence magnetization damping, revealing field-tunable damping effects through a theoretical framework aligned with experimental observations.

Contribution

It introduces a quantum-mechanical boundary condition-based model for spin current exchange in noncollinear spin valves, highlighting non-collinearity-induced damping modulated by magnetic fields.

Findings

Non-collinearity induces additional damping.

Damping can be tuned by applied magnetic fields.

Theoretical predictions agree with experiments.

Abstract

We study the magnetic damping in the simplest of synthetic antiferromagnets, i.e. antiferromagnetically exchange-coupled spin valves in which applied magnetic fields tune the magnetic configuration to become noncollinear. We formulate the dynamic exchange of spin currents in a noncollinear texture based on the spindiffusion theory with quantum mechanical boundary conditions at the ferrromagnet|normal-metal interfaces and derive the Landau-Lifshitz-Gilbert equations coupled by the static interlayer non-local and the dynamic exchange interactions. We predict non-collinearity-induced additional damping that can be sensitively modulated by an applied magnetic field. The theoretical results compare favorably with published experiments.