Thickness dependence of the interfacial Dzyaloshinskii-Moriya interaction in inversion symmetry broken systems

TL;DR

This study investigates how the interfacial Dzyaloshinskii-Moriya interaction varies with magnetic layer thickness in multilayer systems, using Brillouin light scattering to reveal its inverse proportionality to thickness and exploring its potential for magnetic engineering.

Contribution

The paper introduces a straightforward experimental method to observe the IDM interaction and demonstrates its inverse dependence on magnetic layer thickness through combined experimental and theoretical analysis.

Findings

IDM interaction measured via Brillouin light scattering.

IDM energy density inversely proportional to magnetic layer thickness.

Theoretical analysis supports experimental observations.

Abstract

In magnetic multilayer systems, a large spin-orbit coupling at the interface between heavy metals and ferromagnets can lead to intriguing phenomena such as the perpendicular magnetic anisotropy, the spin Hall effect, the Rashba effect, and especially the interfacial Dzyaloshinskii-Moriya (IDM) interaction. This interfacial nature of IDM interaction has been recently revisited because of its scientific and technological potential. Here, we demonstrate an experimental technique to straightforwardly observe the IDM interaction, namely Brillouin light scattering. The non-reciprocal spin wave dispersions, systematically measured by Brillouin light scattering, allow not only the determination of the IDM energy densities beyond the regime of perpendicular magnetization but also the revelation of the inverse proportionality with the thickness of the magnetic layer, which is a clear signature of the interfacial nature. All together, our experimental and theoretical approaches involving double time Green,s function methods open up possibilities for exploring magnetic hybrid structures for engineering the IDM interaction.