透射电镜差分相位分析技术磁畴研究-中国材料进展

文章信息/Info

Title:: Magnetic Domain Imaging by Differential Phase Contrast Technique of Transmission Electronic Microscopy

作者:: 汤进1; 吴耀东1; 2; 熊奕敏1; 田明亮1; 杜海峰1; （1. 中国科学院合肥物质科学研究院强磁场科学中心极端条件凝聚态物理安徽省重点实验室，安徽合肥 230031）（2. 合肥师范学院物理与材料工程学院，安徽合肥 230061）

Author(s):: TANG Jin1; WU Yaodong1; 2; XIONG Yimin1; TIAN Mingliang1; DU Haifeng1; （1. Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China）（2. School of Physics and Materials Engineering, Hefei Normal University, Hefei 230061, China）

Keywords:: transmission electronic microscopy; differential phase contrast; magnetic domain; Skyrmionbubble; centrosymmetric uniaxial magnet

摘要:: 透射电子显微镜具有高空间磁分辨率和易集成的多场调控等特点，成为当下纳米尺度下先进磁结构观测的主要手段之一。首先介绍和比较了透射电镜磁表征的3种模式：洛伦茨模式、电子全息模式和差分相位分析模式，然后详细综述了差分相位分析技术表征一类中心对称晶体Fe3Sn2材料中新型磁畴结构的研究进展。在该研究中，首先结合差分相位分析技术和三维微磁学模拟，阐释了中心对称材料中复杂“多拓扑态”磁畴起源于磁结构的三维特性，随后基于该材料温度诱导自旋重取向内禀物性，在Fe3Sn2受限纳米盘中，利用差分相位分析技术发现了一类全新的涡旋状磁结构“靶磁泡”，研究了其磁场演化行为，最后提出了斯格明子磁泡基存储器的概念，并实现了磁场和电流高度可控斯格明子磁泡拓扑磁转变。差分相位分析技术揭示的中心对称磁性材料纳米结构中的新颖磁畴及丰富的电流驱动动力学，有望促进未来基于新型磁畴结构的拓扑相关自旋电子学器件的开发。

Abstract:: Transmission electronic microscopy (TEM) has become one of the most advanced techniques to observe nanometric-sized magnetic domains, owing to its high spatial magnetic resolution and easy accessibility in integrating multiple physic fields. Here, we compared three techniques of TEM observing magnetic domains: Lorentz-TEM, electronic holography and differential phase contrast scanning TEM (DPCSTEM). Then we reviewed recent advances in magnetic domains imaging of a centrosymmetric magnet Fe3Sn2 by DPC-STEM. We demonstrated physical clarifications to “multiple topological states”, which are attributed to three-dimensional (3D) depth-modulated spin configurations, using DPC-STEM and 3D micromagnetic simulations. We then reported a new class of vortex-like spin configurations named “target bubble” and their field-driven magnetic evolutions in Fe3Sn2 nanodisks. Finally, we proposed a new strategy to design memory named Skyrmion-bubble-based memory, which utilizes Skyrmions and bubbles as binary bits “1” and “0”, respectively. Current-field-controlled topological Skyrmionbubble transformations have been also achieved. The novel magnetic domains and their intriguing electronic-magnetic properties shed by DPC-STEM are expected to facilitate advances in developing topology-related spintronic devices.