Spin-current emission governed by nonlinear spin dynamics

TL;DR

This paper investigates how nonlinear magnetization dynamics in a metal/magnetic insulator bilayer influence spin-current emission, revealing temperature and power-dependent behaviors driven by magnon interactions.

Contribution

It demonstrates that nonlinear magnetization dynamics significantly enhance spin-current emission, highlighting the role of magnon scatterings in this process.

Findings

Spin-current emission depends on temperature and excitation power.

Nonlinear magnetization dynamics are triggered by decreasing temperature.

Magnon scatterings enhance spin-current emission.

Abstract

Coupling between conduction electrons and localized magnetization is responsible for a variety of phenomena in spintronic devices. This coupling enables to generate spin currents from dynamical magnetization. Due to the nonlinearity of magnetization dynamics, the spin-current emission through the dynamical spin-exchange coupling offers a route for nonlinear generation of spin currents. Here, we demonstrate spin-current emission governed by nonlinear magnetization dynamics in a metal/magnetic insulator bilayer. The spin-current emission from the magnetic insulator is probed by the inverse spin Hall effect, which demonstrates nontrivial temperature and excitation power dependences of the voltage generation. The experimental results reveal that nonlinear magnetization dynamics and enhanced spin-current emission due to magnon scatterings are triggered by decreasing temperature. This result illustrates the crucial role of the nonlinear magnon interactions in the spin-current emission driven by dynamical magnetization, or nonequilibrium magnons, from magnetic insulators.