Tuning domain wall velocity with Dzyaloshinskii-Moriya interaction

TL;DR

This study investigates how the Dzyaloshinskii-Moriya interaction influences domain wall velocities in Pt/Co/M trilayers, demonstrating that engineering interfacial DMI can optimize domain wall motion for spintronic devices.

Contribution

It reveals how the top layer material affects DMI strength and domain wall velocity, providing a method to tune magnetic dynamics in trilayer structures.

Findings

Domain wall speed varies with top layer material.

DMI strength correlates with the nature of the top layer.

Domain wall velocities reach several hundred m/s with certain materials.

Abstract

We have studied a series of Pt/Co/M epitaxial trilayers, in which Co is sandwiched between Pt and a non magnetic layer M (Pt, Ir, Cu, Al). Using polar magneto-optical Kerr microscopy, we show that the field- induced domain wall speeds are strongly dependent on the nature of the top layer, they increase going from M=Pt to lighter top metallic overlayers, and can reach several 100 m/s for Pt/Co/Al. The DW dynamics is consistent with the presence of chiral N\'eel walls stabilized by interfacial Dzyaloshinskii-Moriya interaction (DMI) whose strength increases going from Pt to Al top layers. This is explained by the presence of DMI with opposite sign at the Pt/Co and Co/M interfaces, the latter increasing in strength going towards heavier atoms, possibly due to the increasing spin-orbit interaction. This work shows that in non-centrosymmetric trilayers the domain wall dynamics can be finely tuned by engineering the DMI strength, in view of efficient devices for logic and spitronics applications.