The Anhui Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, Chinese Academy of Science (CAS), Hefei, Anhui Province 230031, China.
Department of Physics, University of Science and Technology of China, Hefei, Anhui Province 230031, China.
Nat Commun. 2017 Jun 5;8:15569. doi: 10.1038/ncomms15569.
The ability to controllably manipulate magnetic skyrmions, small magnetic whirls with particle-like properties, in nanostructured elements is a prerequisite for incorporating them into spintronic devices. Here, we use state-of-the-art electron holographic imaging to directly visualize the morphology and nucleation of magnetic skyrmions in a wedge-shaped FeGe nanostripe that has a width in the range of 45-150 nm. We find that geometrically-confined skyrmions are able to adopt a wide range of sizes and ellipticities in a nanostripe that are absent in both thin films and bulk materials and can be created from a helical magnetic state with a distorted edge twist in a simple and efficient manner. We perform a theoretical analysis based on a three-dimensional general model of isotropic chiral magnets to confirm our experimental results. The flexibility and ease of formation of geometrically confined magnetic skyrmions may help to optimize the design of skyrmion-based memory devices.
在纳米结构元件中可控地操纵磁 skyrmion（具有粒子特性的小型磁性旋涡）的能力是将其纳入自旋电子器件的前提条件。在这里，我们使用最先进的电子全息成像技术，直接观察到楔形 FeGe 纳米带中磁 skyrmion 的形态和成核，该纳米带的宽度在 45-150nm 范围内。我们发现，在纳米带中，受几何限制的 skyrmion 能够采用各种尺寸和椭圆度，而在薄膜和体材料中都不存在这些特征，并且可以通过简单有效的方式从具有扭曲边缘扭曲的螺旋磁状态中产生。我们基于各向同性手性磁体的三维通用模型进行了理论分析，以验证我们的实验结果。受几何限制的磁 skyrmion 的灵活性和易于形成可能有助于优化基于 skyrmion 的存储器件的设计。
