Exotic Transverse-Vortex Magnetic Configurations in CoNi Nanowires
Exotic Transverse-Vortex Magnetic Configurations in CoNi Nanowires
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DOI：
10.1021/acsnano.9b07448
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发表时间：
2020-02-01
期刊：
影响因子：
17.1
通讯作者：
Snoeck, Etienne
中科院分区：
文献类型：
--
作者：
Andersen, Ingrid Marie;Alfredo Rodriguez, Luis;Snoeck, Etienne
利用电子全息技术在纳米尺度上定量分析了圆柱形富co纳米线的磁性构型，并将其与局部结构和化学性质进行了关联。纳米线具有面心立方（fcc）和六方密排（hcp）两种晶体结构，晶界平行于纳米线轴线方向。电子全息证明了一种复杂的奇异磁结构的存在，其特征是在一条纳米线内存在两种截然不同的磁结构：在富含hcp的区域中，一组周期性涡旋分离了垂直易轴取向的小横向畴，而在含有fcc颗粒的区域中，一组主要是平行于纳米线轴的轴向结构。这些截然不同的畴被发现是由化学成分的局部变化引起的，这些变化改变了晶体的取向和/或结构，从而引起磁各向异性的变化。微磁模拟，包括实验确定的结构特性，允许更深入地理解电子全息术观察到的复杂磁态。
The magnetic configurations of cylindrical Co-rich CoNi nanowires have been quantitatively analyzed at the nanoscale by electron holography and correlated to local structural and chemical properties. The nanowires display grains of both face-centered cubic (fcc) and hexagonal close packed (hcp) crystal structures, with grain boundaries parallel to the nanowire axis direction. Electron holography evidences the existence of a complex exotic magnetic configuration characterized by two distinctly different types of magnetic configurations within a single nanowire: an array of periodical vortices separating small transverse domains in hcp-rich regions with perpendicular easy axis orientation and a mostly axial configuration parallel to the nanowire axis in regions with fcc grains. These vastly different domains are found to be caused by local variations in the chemical composition modifying the crystalline orientation and/or structure, which give rise to change in magnetic anisotropies. Micromagnetic simulations, including the structural properties that have been experimentally determined, allow for a deeper understanding of the complex magnetic states observed by electron holography.