Department of Physics, Harvard University, 17 Oxford Street, Cambridge, MA, 02138, USA.
Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA, 02138, USA.
Nat Commun. 2018 Jul 13;9(1):2712. doi: 10.1038/s41467-018-05158-9.
Magnetic skyrmions are two-dimensional non-collinear spin textures characterized by an integer topological number. Room-temperature skyrmions were recently found in magnetic multilayer stacks, where their stability was largely attributed to the interfacial Dzyaloshinskii-Moriya interaction. The strength of this interaction and its role in stabilizing the skyrmions is not yet well understood, and imaging of the full spin structure is needed to address this question. Here, we use a nitrogen-vacancy centre in diamond to measure a map of magnetic fields produced by a skyrmion in a magnetic multilayer under ambient conditions. We compute the manifold of candidate spin structures and select the physically meaningful solution. We find a Néel-type skyrmion whose chirality is not left-handed, contrary to preceding reports. We propose skyrmion tube-like structures whose chirality rotates through the film thickness. We show that NV magnetometry, combined with our analysis method, provides a unique tool to investigate this previously inaccessible phenomenon.
磁 skyrmions 是二维非共线自旋纹理，其特征在于整数拓扑数。最近在磁性多层堆栈中发现了室温 skyrmions，其稳定性在很大程度上归因于界面 Dzyaloshinskii-Moriya 相互作用。这种相互作用的强度及其在稳定 skyrmions 中的作用尚不清楚，需要对完整的自旋结构进行成像来解决这个问题。在这里，我们使用金刚石中的氮空位中心来测量在环境条件下磁性多层中 skyrmion 产生的磁场图。我们计算了候选自旋结构的流形，并选择了物理上有意义的解。我们发现了一个 Neel 型 skyrmion，其手性不是左手，与之前的报告相反。我们提出了 skyrmion 管状结构，其手性通过薄膜厚度旋转。我们表明，NV 磁强计结合我们的分析方法提供了一种独特的工具来研究这一以前无法进入的现象。
