Effect of nanostructure layout on spin pumping phenomena in antiferromagnet/ nonmagnetic metal/ ferromagnet multilayered stacks

TL;DR

This study investigates how the layout of nanostructures in multilayer stacks affects spin pumping in antiferromagnet/nonmagnetic metal/ferromagnet systems, revealing a thickness-dependent damping effect relevant for spintronic device design.

Contribution

It provides experimental evidence of the inverse relationship between ferromagnetic layer thickness and spin-pumping linewidth contribution, highlighting the role of AFM spin dynamics.

Findings

Spin-pumping increases linewidth and shifts resonance in FMR spectra.

Linewidth contribution is inversely proportional to ferromagnetic layer thickness.

Results suggest dissipative AFM spin dynamics influence spin pumping.

Abstract

In this work we focus on magnetic relaxation in Mn$_{80}$Ir$_{20}$(12 nm)/ Cu(6 nm)/ Py($d_\mathrm{F}$) antiferromagnet/Cu/ferromagnet (AFM/Cu/FM) multilayers with different thickness of the ferromagnetic permalloy layer. An effective FM-AFM interaction mediated via the conduction electrons in the nonmagnetic Cu spacer -- the spin-pumping effect -- is detected as an increase in the linewidth of the ferromagnetic resonance (FMR) spectra and a shift of the resonant magnetic field. We further find experimentally that the spin-pumping-induced contribution to the linewidth is inversely proportional to the thickness of the Py layer. We show that this thickness dependence likely originates from the dissipative dynamics of the free and localized spins in the AFM layer. The results obtained could be used for tailoring the dissipative properties of spintronic devices incorporating antiferromagnetic layers.