Dzyaloshinskii Moriya interaction across antiferromagnet / ferromagnet interface

TL;DR

This study directly measures the Dzyaloshinskii Moriya interaction at AFM/FM interfaces, revealing its dependence on IrMn thickness and implications for chiral spin textures in spintronic devices.

Contribution

First direct measurement of interfacial DMI across AFM/FM interface using Brillouin light scattering, showing significant enhancement with IrMn thickness.

Findings

DMI is observed across IrMn/CoFeB interface.

DMI strength increases sevenfold with IrMn thickness.

Results suggest potential for chiral spin textures in devices.

Abstract

The antiferromagnet (AFM) / ferromagnet (FM) interfaces are of central importance in recently developed pure electric or ultrafast control of FM spins, where the underlying mechanisms remain unresolved. Here we report the direct observation of Dzyaloshinskii Moriya interaction (DMI) across the AFM/FM interface of IrMn/CoFeB thin films. The interfacial DMI is quantitatively measured from the asymmetric spin wave dispersion in the FM layer using Brillouin light scattering. The DMI strength is enhanced by a factor of 7 with increasing IrMn layer thickness in the range of 1- 7.5 nm. Our findings provide deeper insight into the coupling at AFM/FM interface and may stimulate new device concepts utilizing chiral spin textures such as magnetic skyrmions in AFM/FM heterostructures.