Recent progress on electron- and magnon-mediated torques

TL;DR

This review discusses recent advances in electron- and magnon-mediated spin-orbit torques, highlighting materials, mechanisms, and the potential for next-generation high-speed, low-power magnetic memory devices.

Contribution

It systematically summarizes the generation mechanisms and materials for electron- and magnon-mediated torques, emphasizing recent progress and remaining challenges in the field.

Findings

Key materials enabling SOTs and magnon torques identified

Demonstration of device components shows progress in the field

Many promising materials and mechanisms still require exploration

Abstract

The growing demand for artificial intelligence and complex computing has underscored the urgent need for advanced data storage technologies. Spin-orbit torque (SOT) has emerged as a leading candidate for high-speed, high-density magnetic random-access memory due to its ultrafast switching speed and low power consumption. This review systematically explores the generation and switching mechanisms of electron-mediated torques (including both conventional SOTs and orbital torques) and magnon-mediated torques. We discuss key materials that enable these effects: heavy metals, topological insulators, low-crystal-symmetry materials, non-collinear antiferromagnets, and altermagnets for conventional SOTs; 3d, 4d, and 5d transition metals for orbital torques; and antiferromagnetic insulator NiO- and multiferroic BiFeO3-based sandwich structures for magnon torques. We emphasize that although key components of SOT devices have been demonstrated, numerous promising materials and critical questions regarding their underlying mechanisms remain to be explored. Therefore, this field represents a dynamic and rapidly evolving frontier in spintronics, offering significant potential for advancing next-generation information storage and computational technologies.