Effect of Spin Current on Uniform Ferromagnetism: Domain Nucleation

TL;DR

This paper investigates how spin currents influence ferromagnetic states, revealing that domain nucleation occurs above a critical spin current and is suppressed in states with domain walls, supported by energy comparisons.

Contribution

It demonstrates that spin-wave instability is absent in domain wall states, indicating a new mechanism for domain nucleation under spin current.

Findings

Domain nucleation occurs above a critical spin current.

Spin-wave instability is suppressed in states with domain walls.

Energy analysis supports the stability of domain wall states under spin current.

Abstract

Large spin current applied to a uniform ferromagnet leads to a spin-wave instability as pointed out recently. In this paper, it is shown that such spin-wave instability is absent in a state containing a domain wall, which indicates that nucleation of magnetic domains occurs above a certain critical spin current. This scenario is supported also by an explicit energy comparison of the two states under spin current.