Magnetization switching by magnon-mediated spin torque through an antiferromagnetic insulator.

Wang, Yi; Zhu, Dapeng; Yang, Yumeng; Lee, Kyusup; Mishra, Rahul; Go, Gyungchoon; Oh, Se-Hyeok; Kim, Dong-Hyun et al. · Science · 2019

basic_science · Level V

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Abstract

Widespread applications of magnetic devices require an efficient means to manipulate the local magnetization. One mechanism is the electrical spin-transfer torque associated with electron-mediated spin currents; however, this suffers from substantial energy dissipation caused by Joule heating. We experimentally demonstrated an alternative approach based on magnon currents and achieved magnon-torque-induced magnetization switching in Bi<sub>2</sub>Se<sub>3</sub>/antiferromagnetic insulator NiO/ferromagnet devices at room temperature. The magnon currents carry spin angular momentum efficiently without involving moving electrons through a 25-nanometer-thick NiO layer. The magnon torque is sufficient to control the magnetization, which is comparable with previously observed electrical spin torque ratios. This research, which is relevant to the energy-efficient control of spintronic devices, will invigorate magnon-based memory and logic devices.