Recently, the research team led by Prof. Dong Shuai from the School of Physics, SEU, made significant progress in investigating the physical mechanism of ultrafast magnetization reversal controlled by electric fields. Their research, titled “Magnetoelectric torque in polar magnetic bilayers”, was published in Physical Review Letters, a prestigious academic journal.

Electric-field-controlled magnetization reversal technology holds significant promise for new low-power spintronic devices. However, existing mainstream technologies rely on spin-transfer torque and spin-orbit torque mechanisms, which are generally hindered by the Joule heating problem caused by current injection, preventing devices from achieving ideal power efficiency. Theoretically, magnetoelectric multiferroic materials could achieve magnetization torque reversal purely by electric fields, avoiding the Joule heating issue and thus offering advantages as energy-saving materials. However, current research is limited toType-I multiferroics, driven by ionic, which restricts the speed of magnetoelectric torque reversal to the ion migration speed. Additionally, it has been observed that magnetoelectric effects in two-dimensional systems exhibit behaviors that are different from those in three-dimensional systems. For instance, in the two-dimensional van der Waals magnet CrI?, electrostatic doping can modulate its electronic structure, influencing interlayer magnetic coupling to achieve magnetoelectric torque reversal. However, this doping method can potentially compromise the system’s insulating properties, leading to leakage current.

To address these issues, the team proposed a magnetoelectric torque mechanism to achieve electric field-controlled ultrafast magnetization reversal. Combining theoretical models, first-principles calculations, and atomic-scale simulations, this study thoroughly explored the generation mechanism of magnetoelectric torque and the magnetization reversal process, revealing the origin of ultrafast spin dynamics at terahertz frequencies. The research team further validated that this magnetoelectric torque mechanism is independent of spin-orbit coupling and demonstrates broad universality in two-dimensional van der Waals polar magnetic bilayers.

The first author of the paper is Ph.D. student Shen Zhong from the School of Physics, SEU, with Professors Yao Xiaoyan and Dong Shuai as the corresponding authors. Other contributors include postdoctoral researcher Chen Jun from the School of Physics. SEU is the soleaffiliationfor this research. The study was supported by the National Natural Science Foundation, the Jiangsu Province Graduate Research and Innovation Program, the Jiangsu Province Outstanding Postdoctoral Talent Program, the China Postdoctoral Science Foundation, the Key Laboratory of Quantum Materials and Devices of Ministry of Education at Southeast University, and computational resources from the Big Data Computing Center of Southeast University.

Paper’s link: https://journals.aps.org/prl/pdf/10.1103/l5fd-kpn5

Source: School of Physics, SEU

Translated by: Melody Zhang

Proofread by: Gao Min

Edited by: Li Xinchang