Scanning transmission X-ray microscope observation and quantitative study of magnetic vortex structure

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	Scanning transmission X-ray microscope observation and quantitative study of magnetic vortex structure
	Sun, L; Huo, Y; Zhou, C; Liang, JH; Zhang, XZ; Xu, ZJ; Wang, Y; Wu, YZ; Wu, YZ (reprint author), Fudan Univ, Dept Phys, Shanghai 200433, Peoples R China.
	2015
发表期刊	ACTA PHYSICA SINICA
ISSN	1000-3290
卷号	64 期号:19 页码:—
文章类型	期刊文献
摘要	Magnetic recording has now played an important role in the development of non-volatile information storage technologies, so it becomes essential to quantitatively understand the magnetization distribution in magnetic microstructures. In ferromagnetic disks, squares and triangles with submicron sizes, it is energetically favorable for the magnetization to form a closed in-plane vortex and a perpendicular vortex core at the center. This vortex magnetic structure is a new candidate for future magnetic memory device because both the vortex chirality and the core polarity can be manipulated by applying an external magnetic field or a spin-polarized current. Further development of vortex-based memory devices requires quantitative measurement of vortex domain structures, which is still lacking. In this paper, magnetization configuration in a vortex structure has been quantitatively studied by scanning transmission X-ray microscope (STXM) utilizing X-ray magnetic circular dichroism (XMCD) effect in Shanghai Synchrotron Radiation Facility. Samples have been fabricated on the 100 nm silicon-nitride membranes. The patterns are first transferred to PMMA photoresist using e-beam lithography, then a 50 nm thick Ni80Fe20 film is deposited by e-beam evaporation. Magnetic vortex configurations are characterized with the X-ray energy at Fe L-3 absorption edge and Ni L-3 absorption edge, respectively. The image taken at Fe edge shows greater contrast than that at Ni edge. Experimental results indicate that the magnetic vortex state remains stable in permalloy circle, square and triangle structures with diameters from 2 to 5 mu m. The STXM images indicate that the magnetization in circular geometry changes continuously along the concentric circles without clear domain boundaries. In contrast, magnetization in square geometry consists of four distinct domains with clear diagonal domain boundaries. Similarly, three domains can be observed in triangle geometry. In order to quantify the in-plane magnetization configuration in magnetic vortices, we also use micromagnetic simulation to calculate the magnetization distributions of these three geometries. By extracting M-x along the circular profiles in both experimental and simulated vortex images, we find that the experimental magnetic profiles in the STXM images are consistent with the simulation data quantitatively. These magnetic structures are also studied by magnetic force microscopy (MFM). Since MFM is only sensitive to the dipolar magnetic field around the domain boundary, the MFM images show different configurations from the STXM images.
关键词	Core Nanostructures Permalloy Media
语种	英语
WOS记录号	WOS:000362977400037
引用统计
文献类型	期刊论文
条目标识符	http://ir.sinap.ac.cn/handle/331007/25034
专题	中科院上海应用物理研究所2011-2018年
通讯作者	Wu, YZ (reprint author), Fudan Univ, Dept Phys, Shanghai 200433, Peoples R China.
推荐引用方式 GB/T 7714	Sun, L,Huo, Y,Zhou, C,et al. Scanning transmission X-ray microscope observation and quantitative study of magnetic vortex structure[J]. ACTA PHYSICA SINICA,2015,64(19):—.
APA	Sun, L.,Huo, Y.,Zhou, C.,Liang, JH.,Zhang, XZ.,...&Wu, YZ .(2015).Scanning transmission X-ray microscope observation and quantitative study of magnetic vortex structure.ACTA PHYSICA SINICA,64(19),—.
MLA	Sun, L,et al."Scanning transmission X-ray microscope observation and quantitative study of magnetic vortex structure".ACTA PHYSICA SINICA 64.19(2015):—.

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