Effects of spin current on ferromagnets

TL;DR

This paper investigates how spin-polarized currents influence ferromagnets, revealing current-induced magnetization instability, spin wave generation, chaos, and effects on domain wall dynamics and depinning thresholds.

Contribution

It provides a detailed analysis of spin torque effects on ferromagnet stability, spin wave generation, chaos, and domain wall behavior, highlighting new insights into current-induced magnetic phenomena.

Findings

Large currents cause ferromagnet instability and chaos.

Spin torque affects domain wall structure and depinning.

Analysis of domain wall mass and kinetic energy.

Abstract

When a spin-polarized current flows through a ferromagnet, the local magnetization receives a spin torque. Two consequences of this spin torque are studied. First, the uniformly magnetized ferromagnet becomes unstable if a sufficiently large current is applied. The characteristics of the instability include spin wave generation and magnetization chaos. Second, the spin torque has profound effects on the structure and dynamics of the magnetic domain wall. A detail analysis on the domain wall mass, kinetic energy and wall depinning threshold is given.