Hu Yue, Zhang Senfu, Zhu Yingmei, Song Chengkun, Huang Junfeng, Liu Chen, Meng Xuan, Deng Xia, Zhu Liu, Guan Chaoshuai, Yang Hongxin, Si Mingsu, Zhang Junwei, Peng Yong
School of Materials and Energy, Electron Microscopy Centre of Lanzhou University and Key Laboratory of Magnetism and Magnetic Materials of the Ministry of Education, Lanzhou University, Lanzhou 730000, P. R. China.
Key Laboratory of Magnetism and Magnetic Materials of the Ministry of Education, School of Physical Science and Technology and Electron Microscopy Centre of Lanzhou University, Lanzhou University, Lanzhou 730000, China.
ACS Appl Mater Interfaces. 2022 Jul 27;14(29):34011-34019. doi: 10.1021/acsami.2c07268. Epub 2022 Jul 5.
Magnetic skyrmions are topologically protected spin textures that were found to be promising candidates for next-generation spintronic devices owing to their small size and unique current-induced dynamics. Increasing skyrmions density at designated locations in a controllable manner is a prerequisite to further improve the recording density of magnetic memory devices and relevant spintronics. Here, we demonstrate that a sharp increase in skyrmion density in magnetic multilayer films can be purposefully realized at a site-specific position by ion irradiation, which has industrial applicability. The Cs-scanning transmission electron microscopy and micromagnetic simulation results indicate that the skyrmions density can be sharply increased five times after applying an exposure with an irradiation dose of 1.5 × 10 Ga/cm, and the magnetic field required to create skyrmions is also reduced. The intrinsic physical mechanism of increasing skyrmion density is found to mainly originate from the formation of disorders through Ga irradiation, which can induce a decrease in the nucleation energy barrier of skyrmions. We further show that the artificial skyrmion patterns with tunable density can be intentionally written at specific sites by using a Ga ion beam. This work should contribute a significant step toward eventually realizing the practical recording application of magnetic skyrmions.
磁斯格明子是一种具有拓扑保护的自旋纹理，由于其尺寸小和独特的电流诱导动力学特性，被认为是下一代自旋电子器件的理想候选材料。以可控方式增加指定位置的斯格明子密度是进一步提高磁存储器件及相关自旋电子学记录密度的前提条件。在此，我们证明通过离子辐照能够在特定位置有目的地实现磁性多层膜中斯格明子密度的急剧增加，这具有工业应用价值。Cs扫描透射电子显微镜和微磁模拟结果表明，在施加1.5×10 Ga/cm的辐照剂量曝光后，斯格明子密度可急剧增加五倍，并且产生斯格明子所需的磁场也会降低。发现斯格明子密度增加的内在物理机制主要源于通过Ga辐照形成的无序状态，这会导致斯格明子成核能垒降低。我们进一步表明，利用Ga离子束可以在特定位置有意地写入密度可调的人工斯格明子图案。这项工作应为最终实现磁斯格明子的实际记录应用迈出重要一步。
