Current-induced magnetization switching using electrically-insulating spin-torque generator

TL;DR

This paper demonstrates that oxygen-incorporated platinum oxide can generate spin-orbit torques sufficient for magnetization switching, enabling energy-efficient, voltage-controlled spintronic devices using insulating materials.

Contribution

It introduces a novel method of generating spin-orbit torques using an insulating platinum oxide, allowing electrical switching of magnetization in insulator-based heterostructures.

Findings

Oxygen incorporation turns Pt into an insulator that generates SOTs.

Electrical switching of perpendicular magnetization achieved with Pt oxide.

SOTs from Pt oxide can be controlled via voltage-driven oxygen migration.

Abstract

Current-induced magnetization switching through spin-orbit torques (SOTs) is the fundamental building block of spin-orbitronics. The SOTs generally arise from the spin-orbit coupling of heavy metals. However, even in a heterostructure where a metallic magnet is sandwiched by two different insulators, a nonzero current-induced SOT is expected because of the broken inversion symmetry; an electrical insulator can be a spin-torque generator. Here, we demonstrate current-induced magnetization switching using an insulator. We show that oxygen incorporation into the most widely used spintronic material, Pt, turns the heavy metal into an electrically-insulating generator of the SOTs, enabling the electrical switching of perpendicular magnetization in a ferrimagnet sandwiched by electrically-insulating oxides. We further found that the SOTs generated from the Pt oxide can be controlled electrically through voltage-driven oxygen migration. These findings open a route towards energy-efficient, voltage-programmable spin-orbit devices based on solid-state switching of heavy metal oxidation.