Room-Temperature Switching of Perpendicular Magnetization by Magnon Torques
Guoyi Shi, Wang Fei, Hui Ru Tan, Shishun Zhao, Yakun Liu, Dongsheng Yang, Kyusup Lee, Yuchen Pu, Shuhan Yang, Anjan Soumyanarayanan, Hyunsoo Yang
Abstract
Electron-mediated spin torque provides a fast and efficient method to manipulate magnetization; however, electron motion inevitably brings about the generation of Joule heat and corresponding power consumption. Magnon-mediated spin torque, without involving moving electrons, could circumvent the energy dissipation issue. In this work, we fabricate a sandwich structure of topological insulator/antiferromagnetic insulator/ferromagnet with perpendicular magnetic anisotropy. We find that the magnon current with spin angular momentum can traverse a 25-nm-thick antiferromagnetic $\mathrm{Ni}\mathrm{O}$ layer and effectively switch the perpendicular magnetization of $\mathrm{Co}\text{\ensuremath{-}}\mathrm{Fe}\text{\ensuremath{-}}\mathrm{B}$ at room temperature with a critical switching current density of 4.1 \ifmmode\times\else\texttimes\fi{} ${10}^{6}\phantom{\rule{0.2em}{0ex}}\mathrm{A}/{\mathrm{cm}}^{2}$. The magnon torque efficiency is characterized using spin-torque ferromagnetic resonance measurements to be 0.33 with a magnon diffusion length of 26.6 nm. Our work paves the way for manipulating perpendicular magnetization via magnon torques, facilitating the exploration of magnon-based spintronics with low power consumption.