Imaging skyrmions in synthetic antiferromagnetic multilayers

合成反铁磁多层膜中的斯格明子成像

• 批准号: 2604464
• 金额: --
• 依托单位: University of Glasgow
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2021
• 资助国家: 英国
• 起止时间: 2021 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2604464
• 关键词: Imaging; skyrmions; synthetic; antiferromagnetic; multilayers

Skyrmions are circular magnetic domains/domain walls in magnetic materials and have attracted great interest recently for spintronic applications. By the nature of the materials the skymrions possess a property known as topological protection, which means that they are hard to annihilate when they interact. Additionally when they are formed in multilayer films with antiferromagnetic coupling between the magnetic layers they have no skyrmion Hall angle, so when a spin polarised current is used to move them they move with the direction of charge flow without deviation. The size of the skymrions depend crucially on the multilayer composition in terms of layer composition and thickness etc. In this project skyrmions in different materials systems will be studied. The materials will be characterised by the methods of transmission electron microscopy (TEM) with the magnetic structure imaged by Lorentz imaging modes. Deposition of films will be carried out at the University of Leeds and the characterisation will be performed at the University of Glasgow. Skymrions with sizes less than 100 nm are to be studied.In a continuous thin film system skyrmions tend to form at random positions at a certain nucleation field. Using various approaches we aim to nucleate site specific single isolated skyrmions. This is proposed via localised nanostructured defects and manipulation of the magnetic anisotropy at surface sites. In situ imaging will reveal that site specific nucleation of skyrmions is possible. We will also explore then moving the skyrmions with spin polarised currents to demonstrate possibilities for device application. In addition to TEM work beamline experiments will also be carried out to complement the TEM imaging. The project also involves working with colleagues at the National Physical Laboratory who are also interested in imaging via scanning probe microscopy.This project aligns with EPSRC priorities in investigating new and advanced materials systems for spintronics applications. For example this materials system is a complex multilayer with magnetic and non magnetic layers possessing 3 different magnetic exchange interactions to provide the right environment for skyrmion stabilisation. In principle skyrmions down to a few 10s of nanometres can provide dynamic devices with controllable moving magnetic "bits", but without mechanical moving parts. This could be implemented logic devices or memory storage.

斯格明子是磁性材料中的圆形磁畴/畴壁，最近引起了自旋电子应用的极大兴趣。由于材料的性质，斯格米子具有一种被称为拓扑保护的特性，这意味着它们在相互作用时很难被消灭。此外，当它们形成在磁性层之间具有反铁磁耦合的多层薄膜时，它们不具有斯格明子霍尔角，因此当使用自旋极化电流来移动它们时，它们沿着电荷流的方向移动而没有偏差。斯格明子的尺寸主要取决于层组成和厚度等方面的多层组成。在该项目中，将研究不同材料系统中的斯格明子。这些材料将通过透射电子显微镜 (TEM) 方法进行表征，并通过洛伦兹成像模式对磁性结构进行成像。电影沉积将在利兹大学进行，表征将在格拉斯哥大学进行。尺寸小于 100 nm 的斯格明子将被研究。在连续薄膜系统中，斯格明子倾向于在某个成核场的随机位置形成。使用各种方法，我们的目标是使位点特定的单个孤立斯格明子成核。这是通过局部纳米结构缺陷和表面位置磁各向异性的操纵提出的。原位成像将揭示斯格明子的位点特异性成核是可能的。我们还将探索用自旋极化电流移动斯格明子，以演示设备应用的可能性。除了 TEM 工作外，还将进行光束线实验以补充 TEM 成像。该项目还涉及与国家物理实验室的同事合作，他们也对扫描探针显微镜成像感兴趣。该项目符合 EPSRC 在研究自旋电子学应用的新型和先进材料系统方面的优先事项。例如，该材料系统是一个复杂的多层，具有磁性和非磁性层，具有 3 种不同的磁交换相互作用，为斯格明子稳定提供合适的环境。原则上，低至几十纳米的斯格明子可以提供具有可控移动磁性“位”的动态装置，但没有机械移动部件。这可以通过逻辑设备或存储器来实现。