Asymmetric Magnetic Domain-Wall Motion by the Dzyaloshinskii-Moriya Interaction

TL;DR

This paper investigates the Dzyaloshinskii-Moriya interaction in ultrathin Pt/Co/Pt films, revealing its significant influence on domain-wall behavior and asymmetry in magnetic expansion, which impacts spintronic device physics.

Contribution

It demonstrates the strong DMI effect in Pt/Co/Pt films and its role in stabilizing Neel-type domain walls, providing insights into domain-wall dynamics influenced by DMI.

Findings

DMI causes asymmetric domain-wall expansion under magnetic fields.

DMI stabilizes Neel-type domain walls in ultrathin films.

The DMI effect significantly influences spin-transfer phenomena.

Abstract

We demonstrate here that ultrathin ferromagnetic Pt/Co/Pt films with perpendicular magnetic anisotropy exhibit a sizeable Dzyaloshinskii-Moriya interaction (DMI) effect. Such a DMI effect modifies the domain-wall (DW) energy density and consequently, results in an asymmetric DW expansion driven by an out-of-plane magnetic field under an in-plane magnetic field bias. From an analysis of the asymmetry, the DMI effect is estimated to be strong enough for the DW to remain in the N\'eel-type configuration in contrast to the general expectations of these materials. Our findings emphasize the critical role of the DMI effect on the DW dynamics as the underlying physics of the asymmetries that are often observed in spin-transfer-related phenomena.