Recently, together with Prof. Hyunsoo Yang from the National University of Singapore, Prof. Wang Yi from School of Physics and Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (MMlab) published an important work in the world’s top journal Science: “Magnetization switching by magnon-mediated spin torque through an antiferromagnetic insulator”.

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. The team experimentally demonstrated an alternative approach based on magnon currents and achieved magnon-torque–induced magnetization switching in Bi2Se3/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.

Wang Yi, a professor and doctoral supervisor of School of Physics, engaged in physics and applied research of spintronics devices for 12 consecutive years. At present, his study is mainly on the basic application research of Spin Orbit Torque-Magnetic Random Access Memory (SOT-MRAM).