Correlation between the Dzyaloshinskii-Moriya interaction and the orbital angular momentum at an oxide / ferromagnet interface

TL;DR

This study reveals that oxides at ferromagnet interfaces can induce and enhance Dzyaloshinskii-Moriya interaction, which correlates with orbital angular momentum, highlighting the role of hybridization and charge transfer.

Contribution

It demonstrates experimentally that oxides can generate DMI and establishes a correlation between DMI and orbital angular momentum at the interface.

Findings

Oxides can induce DMI at ferromagnet interfaces.

Oxidation enhances the total DMI in multilayer systems.

DMI correlates with the spectroscopic splitting factor, indicating a link to orbital momentum.

Abstract

We report on the Dzyaloshinskii-Moriya (DMI) interaction at the interface between a ferromagnet and an oxide. We demonstrate experimentally that oxides can give rise to DMI. By comparison of systems comprised of Pt/Co90Fe10/Oxide and Cu/Co90Fe10/Oxide, we also show how oxidation of one interface can enhance and add to the total DMI of that generated by the Pt interface. This is due to the fact that the DMI on both interfaces promotes left-handed chirality. Finally, by use of ferromagnetic resonance spectroscopy, we show that the DMI and the spectroscopic splitting factor, which is a measure of the orbital momentum, are correlated. This indicates the importance of hybridization and charge transfer at the oxide interface for the DMI.