Ultralow Electrical Current Driven Field‐Free Spin‐Orbit Torque Switching of Magnetic Tunnel Junctions by Topological Insulators

作者：Xu Zhang, Xu Zhang, Aitian Chen, Yifan Zhang, Zhaozhuo Zeng, Yaqin Guo, Dongxing Zheng, Baoshan Cui, Chuangwen Wu, Wenjie Song, Shuo Yang, Zijun Luo, Jingfeng Li, G. Gubbiotti, Xiufeng Han, Jinkui Zhao, Peng Yan, Xufeng Kou, Xixiang Zhang, Xixiang Zhang, Hao Wu · 发表于：Advanced Electronic Materials · 年份：2025 · DOI：10.1002/aelm.202500022 · 被引用次数：4 · 研究领域：Magnetic properties of thin films、Advanced Memory and Neural Computing、Topological Materials and Phenomena

Abstract Spin‐orbit torque‐driven magnetic random‐access memory (SOT‐MRAM) is one of the promising candidates for next‐generation memory technologies beyond Moore's law. Due to its separation of writing and reading channels, the 3‐terminal device design significantly improves the device endurance of SOT‐MRAM. However, two major challenges still exist for the perpendicular SOT‐MRAM: the ultrahigh writing current density and the need for an external magnetic field to achieve deterministic switching. In this work, a 3‐terminal SOT‐MRAM device is demonstrated that integrates topological insulators (TIs) by perpendicular magnetic tunnel junction (pMTJ). The giant spin‐orbit torque generated by spin‐momentum‐locked topological surface states significantly reduces the switching current density to as low as 3.0 × 10 5 A cm −2 . The double magnetic layers with different saturation magnetizations are employed as the recording layer of TIs‐pMTJ. Therefore, non‐collinear canted magnetic states are generated during the current‐driven SOT. By breaking the chiral symmetry of these states through interlayer Dzyaloshinskii–Moriya interaction (DMI), the field‐free deterministic SOT switching is achieved. This work demonstrates the topological insulator‐driven magnetic field‐free SOT‐MRAM with ultralow writing density, inspiring the revolution of SOT‐MRAM technology from classical to quantum materials.