Spin Density Waves and Domain Wall Interactions in Nanowires

TL;DR

This paper explores how spin density waves influence domain wall dynamics in ferromagnetic nanowires, revealing that these waves can enhance current-induced domain wall motion and reduce the required current pulses.

Contribution

It demonstrates that spin density waves generated by domain walls can significantly modify and enhance domain wall motion, a novel insight into magnetic nanowire behavior.

Findings

Spin density waves can be coherently propagated by scattering centers.

Spin torque can be enhanced to match exchange and anisotropy energies.

Spin density waves enable domain wall motion with smaller current pulses.

Abstract

We investigated how the dynamics of a domain wall are affected by the presence of spin density waves in a ferromagnetic wire. Domain walls and other scattering centres can cause coherent spin density waves to propagate through a wire when a current is applied. In some cases the spin torque due to these scattered electrons can be enhanced such that it is on a par with the exchange and anisotropy energies controlling the shape and dynamics of the domain wall. In such a case we find that the spin density waves enhance the current induced domain wall motion, allowing for domain wall motion with smaller current pulses. Here we consider a system involving two domain walls and focus on how the motion of the second domain wall is modified by the spin density waves caused by the presence of the first domain wall.