Baumgartner Manuel, Garello Kevin, Mendil Johannes, Avci Can Onur, Grimaldi Eva, Murer Christoph, Feng Junxiao, Gabureac Mihai, Stamm Christian, Acremann Yves, Finizio Simone, Wintz Sebastian, Raabe Jörg, Gambardella Pietro
Department of Materials, ETH Zürich, 8093 Zürich, Switzerland.
IMEC, Kapeldreef 75, 3001 Leuven, Belgium.
Nat Nanotechnol. 2017 Oct;12(10):980-986. doi: 10.1038/nnano.2017.151. Epub 2017 Aug 21.
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 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 10 reversal cycles.
电流感应自旋轨道转矩是操纵自旋电子器件中磁化强度的最有效方法之一，有望用于非易失性存储器和逻辑单元中的快速开关应用。在此，我们报告了在电流脉冲注入期间对Pt/Co/AlO点中自旋轨道转矩驱动的磁化动力学的直接观察。具有25纳米空间分辨率和100皮秒时间分辨率的时间分辨X射线图像显示，通过在点边缘快速形成反向畴以及倾斜畴壁在点上的传播，在亚纳秒电流脉冲持续时间内实现了开关。成核点是确定性的，并且根据磁化强度、电流和外部磁场的符号在四个点象限之间交替。我们的测量揭示了类似阻尼和类似场的自旋轨道转矩以及Dzyaloshinskii-Moriya相互作用的协同作用如何打破磁对称性，并表明在超过10个反转周期内可以获得可重复的开关事件。
