Interfacial Dzyaloshinskii-Moriya interaction and chiral magnetic textures in a ferrimagnetic insulator

TL;DR

This paper demonstrates the presence of strong interfacial Dzyaloshinskii-Moriya interaction in ferrimagnetic insulator heterostructures, enabling efficient chiral magnetic switching and skyrmion formation, which could advance spintronic applications.

Contribution

It reveals the existence and characteristics of interfacial DMI in insulating magnetic heterostructures, a novel finding in the field.

Findings

Strong interfacial DMI observed in TmIG/Pt heterostructures.

DMI exhibits a 1/thickness dependence with longer decay length.

Chiral spin structures and skyrmions enable efficient magnetic switching.

Abstract

The interfacial Dzyaloshinskii-Moriya interaction (DMI) in multilayers of heavy metal and ferromagnetic metals enables the stabilization of novel chiral spin structures such as skyrmions. Magnetic insulators, on the other hand can exhibit enhanced dynamics and properties such as lower magnetic damping and therefore it is of interest to combine the properties enabled by interfacial DMI with insulating systems. Here, we demonstrate the presence of interfacial DMI in heterostructures that include insulating magnetic layers. We use a bilayer of perpendicularly magnetized insulating thulium iron garnet (TmIG) and the heavy metal platinum, and find a surprisingly strong interfacial DMI that, combined with spin-orbit torque results, in efficient switching. The interfacial origin is confirmed through thickness dependence measurements of the DMI, revealing the characteristic 1/thickness dependence with one order of magnitude longer decay length compared to metallic layers. We combine chiral spin structures and spin-orbit torques for efficient switching and identify skyrmions that allow us to establish the GGG/TmIG interface as the origin of the DMI.