2021/04/30 by Qiming Shao, Peng Li, Luqiao Liu +18 · 582 citations
Physics and Astronomy · #Hall effect #Magnetic properties of thin films #Neuromorphic engineering #Quantum and electron transport phenomena #Skyrmion #Spin (aerodynamics) #Spintronics #Thermal management of electronic devices and systems #Topological Materials and Phenomena #Torque #Variety (cybernetics) #cond-mat.mes-hall #physics.app-ph
paper · pdf · doi:10.1109/tmag.2021.3078583
published in IEEE Transactions on Magnetics 57(7), 1-39 (IEEE Magnetics Society) · an invited paper in the "Advances in Magnetics" series
arxiv created 2021/05/06 · arxiv updated 2021/05/07 · openalex created_date 2021/05/10 · openalex publication_date 2021/05/10 · openalex updated_date 2026/08/05
Spin-orbit torque (SOT) is an emerging technology that enables the efficient manipulation of spintronic devices. The initial processes of interest in SOTs involved electric fields, spin-orbit coupling, conduction electron spins and magnetization. More recently interest has grown to include a variety of other processes that include phonons, magnons, or heat. Over the past decade, many materials have been explored to achieve a larger SOT efficiency. Recently, holistic design to maximize the performance of SOT devices has extended material research from a nonmagnetic layer to a magnetic layer. The rapid development of SOT has spurred a variety of SOT-based applications. In this Roadmap paper, we first review the theories of SOTs by introducing the various mechanisms thought to generate or control SOTs, such as the spin Hall effect, the Rashba-Edelstein effect, the orbital Hall effect, thermal gradients, magnons, and strain effects. Then, we discuss the materials that enable these effects, including metals, metallic alloys, topological insulators, two-dimensional materials, and complex oxides. We also discuss the important roles in SOT devices of different types of magnetic layers. Afterward, we discuss device applications utilizing SOTs. We discuss and compare three-terminal and two-terminal SOT-magnetoresistive random-access memories (MRAMs); we mention various schemes to eliminate the need for an external field. We provide technological application considerations for SOT-MRAM and give perspectives on SOT-based neuromorphic devices and circuits. In addition to SOT-MRAM, we present SOT-based spintronic terahertz generators, nano-oscillators, and domain wall and skyrmion racetrack memories. This paper aims to achieve a comprehensive review of SOT theory, materials, and applications, guiding future SOT development in both the academic and industrial sectors.