Anatomy of Dzyaloshinskii-Moriya Interaction at Co/Pt Interfaces

TL;DR

This paper uses first principles calculations to analyze the microscopic mechanisms of Dzyaloshinskii-Moriya Interaction at Co/Pt interfaces, revealing its interfacial origin and independence from proximity magnetism, aiding device optimization.

Contribution

It provides a detailed microscopic understanding of DMI at Co/Pt interfaces, highlighting its primary interfacial origin and lack of correlation with proximity magnetism, which was previously unclear.

Findings

DMI is mainly located at the interfacial Co layer.

DMI originates from spin-orbit energy in the NM layer.

No direct correlation between DMI and proximity-induced magnetism in Pt.

Abstract

The Dzyaloshinskii-Moriya Interaction (DMI) between spins is induced by spin-orbit coupling in magnetic materials lacking inversion symmetry. DMI is recognized to play a crucial role at the interface between ferromagnetic (FM) and heavy nonmagnetic (NM) metals to create topological textures called magnetic skyrmions which are very attractive for ultra-dense information storage and spintronic devices. DMI also plays an essential role for fast domain wall (DW) dynamics driven by spin-orbit torques. Here, we present first principles calculations which clarify the main features and microscopic mechanisms of DMI in Co/Pt bilayers. DMI is found to be predominantly located at the interfacial Co layer, originating from spin-orbit energy provided by the adjacent NM layer. Furthermore, no direct correlation is found between DMI and proximity induced magnetism in Pt. These results clarify underlying mechanisms of DMI at FM/NM bilayers and should help optimizing material combinations for skyrmion- and DW-based storage and memory devices.