Spin-orbit torque characterization in a nutshell

TL;DR

This paper reviews various experimental techniques for quantifying spin-orbit torques in magnetic heterostructures, highlighting their principles, strengths, limitations, and remaining challenges in the field of spintronics.

Contribution

It provides a comprehensive summary of the most popular methods for SOT quantification, including their variations, error sources, and practical considerations, aiding future research and device development.

Findings

Summarizes key SOT measurement techniques and their principles.

Identifies common sources of error and limitations in SOT quantification.

Discusses ongoing challenges in accurately understanding and measuring SOTs.

Abstract

Spin current and spin torque generation through the spin-orbit interactions in solids, of bulk or interfacial origin, is at the heart of spintronics research. The realization of spin-orbit torque (SOT) driven magnetic dynamics and switching in diverse magnetic heterostructures also pave the way for developing SOT magnetoresistive random access memory and other novel SOT memory and logic devices. Of scientific and technological importance are accurate and efficient SOT quantification techniques, which have been abundantly developed in the last decade. In this article, we summarize popular techniques to experimentally quantify SOTs in magnetic heterostructures at micro- and nano-scale. For each technique, we give an overview of its principle, variations, strengths, shortcomings, error sources, and any cautions in usage. Finally, we discuss the remaining challenges in understanding and quantifying the SOTs in heterostructures.