Chirality-inverted Dzyaloshinskii-Moriya interaction

TL;DR

This paper reports the discovery of a chirality-inverted Dzyaloshinskii-Moriya interaction in a Co double layer on Ir(001), revealing complex atomistic DMI patterns and their potential generality in magnetic nanostructures.

Contribution

It demonstrates the presence of a chirality-inverted DMI in a specific system and provides insights into its atomistic pattern and potential universality.

Findings

Chirality-inverted DMI observed in Co double layer on Ir(001)

Complex atomistic DMI patterns in epitaxial magnetic structures

Potential generality of the effect in magnetic nanostructures

Abstract

The Dzyaloshinskii-Moriya interaction (DMI) is an antisymmetric exchange interaction, which is responsible for the formation of topologically protected spin textures in chiral magnets. Here, by measuring the dispersion relation of the DM energy, we quantify the atomistic DMI in a model system, i.e., a Co double layer on Ir(001). We unambiguously demonstrate the presence of a chirality-inverted DMI, i.e., a sign change in the chirality index of DMI from negative to positive, when comparing the interaction between nearest neighbors to that between neighbors located at longer distances. The effect is in analogy to the change in the character of the Heisenberg exchange interaction from, e.g., ferromagnetic to antiferromagnetic. We show that the pattern of the atomistic DMI in epitaxial magnetic structures can be very complex and provide critical insights into the nature of DMI. We anticipate that the observed effect is general and occurs in many magnetic nanostructures grown on heavy-element metallic substrates.