Song Chengkun, Jin Chendong, Xia Haiyan, Yunxu Ma, Wang Jianing, Liu Qingfang, Wang Jianbo
Key Laboratory for Magnetism and Magnetic Materials - Ministry of Education, Lanzhou University, Lanzhou, People's Republic of China, Lanzhou, Gansu, 730000, CHINA.
Lanzhou University, Lanzhou, People's Republic of China, Lanzhou, Gansu, 730000, CHINA.
J Phys Condens Matter. 2021 Jan 11. doi: 10.1088/1361-648X/abda7e.
Magnetic skyrmions have been proposed as promising information carriers in the application of spintronics, while the material imperfections are inevitable, thus an understanding of pinning effects on skyrmions in confined geometry is crucial for both fundamental research and development of spintronic devices. Here, we present the interactions of a skyrmion with a point and an extended ring defect, in a Co nanodisk which can be applied in skyrmion oscillator, based on micromagnetic simulations. By comparing with the skyrmion preferred position which is in the nanodisk center without defects, we identify the pinning strength and skyrmion preferred positions with a point defect as a function of skyrmion-defect distance and different local parameters of defect region being considered. The pinning centers range from skyrmion center, domain wall and off-center regions. We find a confinement effect on the skyrmion size with a ring defect. Moreover, we also show the rotation of the skyrmion in the presence of a ring defect, that can lead to a variation of oscillation frequency in a large range. These findings provide a complete understanding of the interaction between skyrmion and defects in a nanodisk and may provide a guidance for the design of skyrmion oscillators.
磁斯格明子已被提议作为自旋电子学应用中很有前景的信息载体，然而材料缺陷不可避免，因此了解在受限几何结构中斯格明子的钉扎效应对于自旋电子器件的基础研究和开发都至关重要。在此，基于微磁模拟，我们展示了在可应用于斯格明子振荡器的钴纳米盘中，一个斯格明子与一个点缺陷和一个扩展环形缺陷的相互作用。通过与无缺陷时位于纳米盘中心的斯格明子偏好位置进行比较，我们确定了存在点缺陷时的钉扎强度和斯格明子偏好位置，它们是斯格明子 - 缺陷距离以及所考虑的缺陷区域不同局部参数的函数。钉扎中心范围从斯格明子中心、畴壁和偏心区域。我们发现环形缺陷对斯格明子尺寸有约束效应。此外，我们还展示了存在环形缺陷时斯格明子的旋转，这会导致振荡频率在很大范围内变化。这些发现为全面理解纳米盘中斯格明子与缺陷之间的相互作用提供了依据，并且可能为斯格明子振荡器的设计提供指导。
