Spin Hall torque driven chiral domain walls in magnetic heterostructures

TL;DR

This paper investigates how spin Hall torque influences the motion of chiral domain walls in ultrathin magnetic heterostructures, revealing the role of interface control and material properties in domain wall dynamics.

Contribution

It provides experimental and theoretical insights into current-driven domain wall motion, highlighting the impact of heavy metal underlayers and chirality on magnetic behavior.

Findings

Domain walls move along or against current depending on underlayer material.

The direction of domain wall motion is linked to chirality of the domain wall.

The Dzyaloshinskii-Moriya exchange constant is extracted from the model.

Abstract

The motion of magnetic domain walls in ultrathin magnetic heterostructures driven by current via the spin Hall torque is described. We show results from perpendicularly magnetized CoFeB|MgO heterostructures with various heavy metal underlayers. The domain wall moves along or against the current flow depending on the underlayer material. The direction to which the domain wall moves is associated with the chirality of the domain wall spiral formed in these heterostructures. The one-dimensional model is used to describe the experimental results and extract parameters such as the Dzyaloshinskii-Moriya exchange constant which is responsible for the formation of the domain wall spiral. Fascinating effects arising from the control of interfaces in magnetic heterostructures are described.