Phase-Change Control of Interlayer Exchange Coupling

TL;DR

This study demonstrates how VO2's phase change can reversibly control the interlayer exchange coupling in magnetic multilayers, enabling in-situ tuning of magnetic properties for advanced spintronic applications.

Contribution

It introduces the use of VO2 as a phase-change spacer layer to dynamically modulate magnetic coupling in multilayers, a novel approach in spintronics.

Findings

VO2 films grown successfully at room temperature via sputtering

Interlayer coupling switches from antiferromagnetic to ferromagnetic with phase change

Electronic structure change from insulating to metallic explains coupling modulation

Abstract

Changing the interlayer exchange coupling between magnetic layers in-situ is a key issue of spintronics, as it allows for the optimization of properties that are desirable for applications, including magnetic sensing and memory. In this paper, we utilize the phase change material VO2 as a spacer layer to regulate the interlayer exchange coupling between ferromagnetic layers with perpendicular magnetic anisotropy. The successful growth of ultra-thin (several nanometres) VO2 films is realized by sputtering at room temperature, which further enables the fabrication of [Pt/Co]2/VO2/[Co/Pt]2 multilayers with distinct interfaces. Such a magnetic multilayer exhibits an evolution from antiferromagnetic coupling to ferromagnetic coupling as the VO2 undergoes a phase change. The underlying mechanism originates from the change in the electronic structure of the spacer layer from an insulating to a metallic state. As a demonstration of phase change spintronics, this work may reveal the great potential of material innovations for next-generation spintronics.