Tan Anthony K C, Ho Pin, Lourembam James, Huang Lisen, Tan Hang Khume, Reichhardt Cynthia J O, Reichhardt Charles, Soumyanarayanan Anjan
Data Storage Institute, Agency for Science, Technology & Research (A*STAR), Singapore, Singapore.
Cavendish Laboratory, University of Cambridge, Cambridge, UK.
Nat Commun. 2021 Jul 12;12(1):4252. doi: 10.1038/s41467-021-24114-8.
Magnetic skyrmions are nanoscale spin textures touted as next-generation computing elements. When subjected to lateral currents, skyrmions move at considerable speeds. Their topological charge results in an additional transverse deflection known as the skyrmion Hall effect (SkHE). While promising, their dynamic phenomenology with current, skyrmion size, geometric effects and disorder remain to be established. Here we report on the ensemble dynamics of individual skyrmions forming dense arrays in Pt/Co/MgO wires by examining over 20,000 instances of motion across currents and fields. The skyrmion speed reaches 24 m/s in the plastic flow regime and is surprisingly robust to positional and size variations. Meanwhile, the SkHE saturates at ∼22, is substantially reshaped by the wire edge, and crucially increases weakly with skyrmion size. Particle model simulations suggest that the SkHE size dependence - contrary to analytical predictions - arises from the interplay of intrinsic and pinning-driven effects. These results establish a robust framework to harness SkHE and achieve high-throughput skyrmion motion in wire devices.
磁性斯格明子是一种纳米级自旋纹理,被誉为下一代计算元件。当受到横向电流作用时,斯格明子会以相当快的速度移动。它们的拓扑电荷会导致一种额外的横向偏转,即斯格明子霍尔效应(SkHE)。尽管前景广阔,但它们在电流、斯格明子尺寸、几何效应和无序状态下的动力学现象仍有待确定。在此,我们通过研究超过20000个在电流和磁场中运动的实例,报告了在Pt/Co/MgO线中形成密集阵列的单个斯格明子的整体动力学。在塑性流动状态下,斯格明子速度达到24米/秒,并且对位置和尺寸变化具有惊人的鲁棒性。同时,SkHE在约22时达到饱和,受到线边缘的显著重塑,并且关键的是,它随斯格明子尺寸的增加而微弱增加。粒子模型模拟表明,与分析预测相反,SkHE的尺寸依赖性源于本征效应和钉扎驱动效应的相互作用。这些结果建立了一个强大的框架,以利用SkHE并在线器件中实现高通量斯格明子运动。