Tuning Dzyaloshinskii-Moriya Interaction in Ferrimagnetic GdCo: A First Principles Approach

TL;DR

This study uses first principles calculations to demonstrate how the Dzyaloshinskii-Moriya Interaction in ferrimagnetic Pt/GdCo/Pt1-xWx trilayers can be tuned via cap layer composition, revealing rapid increases with W and potential for skyrmion control.

Contribution

It provides a systematic first principles analysis of DMI tuning in ferrimagnetic trilayers, highlighting the effect of cap layer composition and atomic configuration.

Findings

DMI increases rapidly with ~10% W in the cap layer and saturates.

DMI values depend on atomic configuration at the interface.

W cap layer favors higher DMI than Ta and Ir due to d-band alignment.

Abstract

We present a systematic analysis of our ability to tune chiral Dzyaloshinskii-Moriya Interactions (DMI) in compensated ferrimagnetic Pt/GdCo/Pt1-xWx trilayers by cap layer composition. Using first principles calculations, we show that the DMI increases rapidly for only ~ 10% W and saturates thereafter, in agreement with experiments. The calculated DMI shows a spread in values around the experimental mean, depending on the atomic configuration of the cap layer interface. The saturation is attributed to the vanishing of spin orbit coupling energy at the cap layer and the simultaneous constancy at the bottom interface. Additionally, we predict the DMI in Pt/GdCo/X (X=Ta, W, Ir) and find that W in the cap layer favors a higher DMI than Ta and Ir that can be attributed to the difference in d-band alignment around the Fermi level. Our results open up exciting combinatorial possibilities for controlling the DMI in ferrimagnets towards nucleating and manipulating ultrasmall high-speed skyrmions.