Current induced transverse spin-wave instability in thin ferromagnets: beyond linear stability analysis

TL;DR

This paper investigates how large unpolarized currents induce spin-wave instabilities in thin ferromagnets, exploring nonlinear dynamics and chaos beyond linear stability analysis through simulations and perturbative methods.

Contribution

It provides a detailed analysis of current-induced spin-wave instabilities beyond linear theory, including numerical simulations of chaotic magnetization dynamics in thin ferromagnets.

Findings

Hierarchy of instabilities observed at high currents

Chaotic magnetization dynamics identified

Instabilities occur without applied magnetic field

Abstract

A sufficiently large unpolarized current can cause a spin-wave instability in thin nanomagnets with asymmetric contacts. The dynamics beyond the instability is understood in the perturbative regime of small spin-wave amplitudes, as well as by numerically solving a discretized model. In the absence of an applied magnetic field, our numerical simulations reveal a hierarchy of instabilities, leading to chaotic magnetization dynamics for the largest current densities we consider.