Spin-Orbit Torque Switching in an All-Van der Waals Heterostructure.

Shin, Inseob; Cho, Won Joon; An, Eun-Su; Park, Sungyu; Jeong, Hyeon-Woo; Jang, Seong; Baek, Woon Joong; Park, Seong Yong et al. · Adv Mater · 2022

basic_science · Level V

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Abstract

Current-induced control of magnetization in ferromagnets using spin-orbit torque (SOT) has drawn attention as a new mechanism for fast and energy efficient magnetic memory devices. Energy-efficient spintronic devices require a spin-current source with a large SOT efficiency (ξ) and electrical conductivity (σ), and an efficient spin injection across a transparent interface. Herein, single crystals of the van der Waals (vdW) topological semimetal WTe<sub>2</sub>  and vdW ferromagnet Fe<sub>3</sub> GeTe<sub>2</sub> are used to satisfy the requirements in their all-vdW-heterostructure with an atomically sharp interface. The results exhibit values of ξ ≈ 4.6 and σ ≈ 2.25 × 10<sup>5</sup>  Ω<sup>-1</sup> m<sup>-1</sup> for WTe<sub>2</sub> . Moreover, the significantly reduced switching current density of 3.90 × 10<sup>6</sup> A cm<sup>-2</sup> at 150 K is obtained, which is an order of magnitude smaller than those of conventional heavy-metal/ferromagnet thin films. These findings highlight that engineering vdW-type topological materials and magnets offers a promising route to energy-efficient magnetization control in SOT-based spintronics.