Direct observation of dynamic modes excited in a magnetic insulator by pure spin current

TL;DR

This study provides the first spatially-resolved observation of magnetization modes excited by pure spin currents in insulating Yttrium Iron Garnet disks, revealing nonlinear behaviors that influence spin current interactions in low-damping magnetic insulators.

Contribution

It presents the first spatially-resolved analysis of spin-current-induced dynamic modes in insulating magnetic materials, highlighting nonlinear mode broadening effects.

Findings

Modes exhibit nonlinear self-broadening preventing magnetic bullet formation

Efficient nonlinear mode coupling influences spin current interactions

Insights into magnetization dynamics in low-damping insulators

Abstract

Excitation of magnetization dynamics by pure spin currents has been recently recognized as an enabling mechanism for spintronics and magnonics, which allows implementation of spin-torque devices based on low-damping insulating magnetic materials. Here we report the first spatially-resolved study of the dynamic modes excited by pure spin current in nanometer-thick microscopic insulating Yttrium Iron Garnet disks. We show that these modes exhibit nonlinear self-broadening preventing the formation of the self-localized magnetic bullet, which plays a crucial role in the stabilization of the single-mode magnetization oscillations in all-metallic systems. This peculiarity associated with the efficient nonlinear mode coupling in low-damping materials can be among the main factors governing the interaction of pure spin currents with the dynamic magnetization in high-quality magnetic insulators.