Multi-mode switching by Dzyaloshinskii–Moriya interaction and spin–orbit torque in magnetic tunnel junction

The Dzyaloshinskii–Moriya interaction (DMI), an asymmetric exchange interaction, has attracted significant interest in enabling novel magnetization dynamics. In this work, we demonstrated multi-mode switching in a magnetic tunnel junction (MTJ): unipolar switching (toggle switching), where the switching direction is independent of current polarity, and bipolar switching (deterministic switching), where the final magnetization state depends on current polarity once the current density exceeds a threshold. Through analyzing the magnetic evolution, we qualitatively revealed the underlying mechanism of mode transition under the combined action of DMI, spin–orbit torque(SOT), and external magnetic field. We further analyzed key factors such as magnetic anisotropy and uniform exchange interaction, highlighting their competing effects with DMI in determining switching dynamics. In addition, geometric analysis reveals that circular MTJs with smaller diameters tend to favor unipolar switching, and the multi-mode behavior remains robust even in the presence of edge defects. This work provides a basic understanding of DMI-driven multi-mode switching in magnetic random-access memory (MRAM) and offers valuable guidance for the development of next-generation magnetic memory technologies.