Synthetic antiferromagnetic coupling between ultra-thin insulating garnets

TL;DR

This paper demonstrates synthetic antiferromagnetic coupling in ultra-thin insulating garnet bilayers, revealing potential for insulating spintronic devices with novel magnetic properties and memory applications.

Contribution

It introduces an all-insulating synthetic antiferromagnet using garnet bilayers, showing antiparallel magnetic coupling in insulating materials, which is a novel development in spintronics.

Findings

YIG and GdIG couple antiparallel in bilayers

Demonstration of insulating synthetic antiferromagnet

Memory device with orthogonal magnetization switching

Abstract

The use of magnetic insulators is attracting a lot of interest due to a rich variety of spin-dependent phenomena with potential applications to spintronic devices. Here we report ultra-thin yttrium iron garnet (YIG) / gadolinium iron garnet (GdIG) insulating bilayers on gadolinium iron garnet (GGG). From spin Hall magnetoresistance (SMR) and X-ray magnetic circular dichroism measurements, we show that the YIG and GdIG magnetically couple antiparallel even in moderate in-plane magnetic fields. The results demonstrate an all-insulating equivalent of a synthetic antiferromagnet in a garnet-based thin film heterostructure and could open new venues for insulators in magnetic devices. As an example, we demonstrate a memory element with orthogonal magnetization switching that can be read by SMR.