Dynamics and inertia of skyrmionic spin structures
Dynamics and inertia of skyrmionic spin structures
复制标题
DOI：
10.1038/nphys3234
复制
发表时间：
2015-03-01
期刊：
影响因子：
19.6
通讯作者：
Eisebitt, S.
中科院分区：
文献类型：
--
作者：
Buettner, Felix;Moutafis, C.;Eisebitt, S.
Skyrmions是一种受拓扑保护的缠绕矢量场，其特征为球状拓扑(1)。磁性Skyrmions可能是各种相互作用相互作用的结果，包括在磁泡(2-4)的情况下的交换、偶极和各向异性能量，以及在手性Skyrmions的情况下的额外的Dzyaloshinskii-Moriya相互作用(5)。虽然Skyrmions的静态和低频动力学已经得到很好的控制(6-9)，但它们的千兆赫动力学行为(2)还没有在真实空间中直接观察到。在这里，我们成像了单个磁泡的千兆赫兹回转本征模动力学，并利用它的轨迹实验证实了它的Skyrmion拓扑。这条特殊的轨道指向强惯性的存在，其质量比现有理论预测的要大得多。这一质量是由天空粒子的拓扑限制和与其大小变化相关的能量所赋予的。因此，它有望在磁系统及其以外的所有天离子结构中被发现。我们的实验表明，质量项在描述Skyrmion动力学中起着关键作用。
Skyrmions are topologically protected winding vector fields characterizedby a spherical topology(1). Magnetic skyrmions can arise as the result of the interplay of various interactions, including exchange, dipolar and anisotropy energy in the case of magnetic bubbles(2-4) and an additional Dzyaloshinskii-Moriya interaction in the case of chiral skyrmions(5). Whereas the static and low-frequency dynamics of skyrmions are already well under control(6-9), their gigahertz dynamical behaviour(2) has not been directly observed in real space. Here, we image the gigahertz gyrotropic eigenmode dynamics of a single magnetic bubble and use its trajectory to experimentally confirm its skyrmion topology. The particular trajectory points to the presence of strong inertia, with a mass much larger than predicted by existing theories. This mass is endowed by the topological confinement of the skyrmion and the energy associated with its size change. It is thereby expected to be found in all skyrmionic structures in magnetic systems and beyond. Our experiments demonstrate that the mass term plays a key role in describing skyrmion dynamics.