Recently, the team led by Professor Dong Shuai from the School of Physics, Southeast University, has made progress in the physical mechanism of ultrafast magnetic moment reversal controlled by an electric field. The work was published in Physical Review Letters entitled "Magnetoelectric torque in polar magnetic bilayers".
Electric-field-controlled magnetic moment reversal is not only a hot topic in fundamental condensed matter physics but also holds great potential for applications in novel low-power spintronic devices. Current mainstream technologies for electric-field-controlled magnetic reversal are mainly based on spin-transfer torque and spin-orbit torque, both of which require current injection. As a result, Joule heating is unavoidable, leading to unsatisfactory power consumption for such devices. In contrast, magnetoelectric multiferroic materials offer the possibility of reversing magnetic moments using a pure electric field, thereby eliminating Joule heating caused by current injection and being theoretically more energy-efficient. However, most existing studies are limited to Type-I multiferroics mediated by ionic displacement, so the speed of magnetic moment reversal is restricted by the rate of ionic motion. With the rapid development of two-dimensional (2D) materials, researchers have found that magnetoelectric effects in 2D systems often exhibit distinct behaviors compared to their three-dimensional (3D) counterparts. For instance, in 2D van der Waals magnets (e.g., CrI₃), electrostatic doping can be used to tune the electronic structure, thereby modifying interlayer magnetic coupling and realizing magnetic moment reversal. Nevertheless, doping may degrade the insulating nature of the system and cause leakage currents.
To address the above issues, Professor Dong Shuai’s team proposed a magnetoelectric torque mechanism to achieve ultrafast, electric-field-controllable magnetic moment reversal. Using theoretical modeling, first-principles calculations, and atomic-scale simulations, the team thoroughly investigated the origin of magnetoelectric torque and the magnetic moment reversal process, revealing the underlying terahertz-frequency ultrafast spin dynamics. Furthermore, this magnetoelectric torque mechanism does not rely on spin-orbit coupling and is widely applicable to 2D van der Waals polar magnetic bilayers.
The first author of the paper is Shen Zhong, a PhD candidate at the School of Physics, Southeast University. Professor Yao Xiaoyan and Professor Dong Shuai are the corresponding authors. Postdoctoral researcher Chen Jun from the School of Physics also contributed to this work. Southeast University is the sole affiliation of the paper. This research was supported by the National Natural Science Foundation of China, the Postgraduate Research and Innovation Program of Jiangsu Province, the Excellent Postdoctoral Talent Support Program of Jiangsu Province, the China Postdoctoral Science Foundation, the Key Laboratory of Quantum Materials and Information Devices (Ministry of Education) at Southeast University, and the Big Data Computing Center of Southeast University.
Link: https://journals.aps.org/prl/pdf/10.1103/l5fd-kpn5
