The development of approaches that can efficiently control the magnetization of magnetic materials is central to the creation of fast and low-power spintronic devices. Spin transfer torque can be used to electrically manipulate magnetic order in devices, but is typically limited to nanosecond timescales. Alternatively, spin–orbit torque can be employed, and switching with current pulses down to ~200 ps has been demonstrated. However, the upper limit to magnetization switching speed remains unestablished. Here, we show that photoconductive switches can be used to apply 6-ps-wide electrical pulses and deterministically switch the out-of-plane magnetization of a common thin cobalt film via spin–orbit torque. We probe the ultrafast magnetization dynamics due to spin–orbit torques with sub-picosecond resolution using the time-resolved magneto-optical Kerr effect (MOKE). We also estimate that the magnetization switching consumes less than 50 pJ in micrometre-sized devices.

能够有效控制磁性材料磁化的方法的开发对于创建快速和低功率自旋电子器件至关重要。自旋传递扭矩可用于电气操纵设备中的磁序，但通常限于纳秒级。另外，也可以使用自旋轨道转矩，并且已经证明了以低至200 ps的电流脉冲进行切换。但是，磁化切换速度的上限尚未确定。在这里，我们表明光电导开关可用于施加6 ps宽的电脉冲，并通过自旋轨道转矩确定性地切换普通钴薄膜的面外磁化强度。我们使用时间分辨的磁光克尔效应（MOKE）探测了亚微微秒级分辨率的自旋轨道转矩引起的超快磁化动力学。我们还估计，在微米级的设备中，磁化切换的功耗小于50 pJ。