Current-induced spin–orbit torques are one of the most effective ways to manipulate the magnetization in spintronic devices, and hold promise for fast switching applications in non-volatile memory and logic units. Here, we report the direct observation of spin–orbit-torque-driven magnetization dynamics in Pt/Co/AlO_x dots during current pulse injection. Time-resolved X-ray images with 25 nm spatial and 100 ps temporal resolution reveal that switching is achieved within the duration of a subnanosecond current pulse by the fast nucleation of an inverted domain at the edge of the dot and propagation of a tilted domain wall across the dot. The nucleation point is deterministic and alternates between the four dot quadrants depending on the sign of the magnetization, current and external field. Our measurements reveal how the magnetic symmetry is broken by the concerted action of the damping-like and field-like spin–orbit torques and the Dzyaloshinskii–Moriya interaction, and show that reproducible switching events can be obtained for over 10¹² reversal cycles.

电流感应的自旋轨道转矩是控制自旋电子器件中磁化强度的最有效方法之一，并有望在非易失性存储器和逻辑单元中实现快速开关应用。在这里，我们报告了在Pt / Co / AlO _x中自旋轨道转矩驱动的磁化动力学的直接观察当前脉冲注入期间的点。具有25 nm空间和100 ps时间分辨率的时间分辨X射线图像显示，通过在点边缘倒置畴的快速成核和倾斜畴壁的传播，可以在亚纳秒电流脉冲的持续时间内实现切换跨点。成核点是确定性的，并根据磁化，电流和外部磁场的符号在四个点象限之间交替。我们的测量揭示了如何通过类似阻尼和类似磁场的自旋轨道转矩以及Dzyaloshinskii-Moriya相互作用的协同作用来破坏磁对称性，并表明在超过10 ^12个反向循环中可以获得可再现的开关事件。