Detection and Manipulation of Magnetic Skyrmion Domains in Silicide and Germanide Nanowires for Spintronic Applications

用于自旋电子学应用的硅化物和锗化物纳米线中磁斯格明子域的检测和操纵

• 批准号: 1231916
• 负责人: Song Jin
• 金额: $ 28.88万
• 依托单位: University of Wisconsin-Madison
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-09-01 至 2015-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1231916&HistoricalAwards=false
• 关键词: Detection; Manipulation; Magnetic; Skyrmion; Domains

This project seeks to utilize chiral magnetic Skyrmion domains in nanowires of silicides and germanides for magnetic data storage applications. Skyrmions are a novel type of exotic magnetic ordering in which electron spins orient to form a topologically non-trivial whirlpool-like structure. They were recently discovered in non-centrosymmetric B20 monosilicides (MnSi, Fe1-xCoxSi) or monogermanide (FeGe). Skyrmions can be thought of as magnetic knots, quasi-particle-like domains that are stable to small perturbations in magnetic field and temperature and do not pin strongly to the crystal lattice or impurities. Skyrmions strongly couple to electrical currents due to the spin torque interaction therefore much lower critical current density is needed to drive the motion of Skyrmion domains. Skyrmions present novel opportunities for implementing spintronic and magnetic storage device designs. Furthermore, nanowires present an ideal system to realize, detect, and manipulate isolated chiral magnetic Skyrmions in the absence of an applied magnetic field due to the stabilization of the Skyrmion phase in confined one-dimensional geometry. Building on their progress in the growth of metal silicide and germanide nanowires and the expertise in spintronic device investigations using nanowire building blocks,PI plan to observe, measure, and manipulate chiral Skyrmions in nanowires of non-centrosymmetric B20 silicides, such as Fe1-xCoxSi and MnSi. Specifically, through an international collaboration with the University of Tokyo, Lorentz transmission electron microscopy will be used to visualize Skyrmions in these nanowires. Furthermore, topological Hall effect due to Skyrmions will be electrically measured in nanowires. Finally, the emergent dynamics of Skyrmions and their motions will be investigated in nanowire electrical devices. The intellectual merit: This research project presents the first opportunity for observing and electrically detecting Skyrmion motion by integrating existing nanowire materials with careful device and physical studies. Nanowire geometry has several advantages over thin film and bulk samples and is better suited for demonstrating such novel phenomenon therefore nanowires can serve as a model material platform that takes the study of Skyrmions from the fundamental physics and to more applied device work and eventual applications. Due to their unique and superior properties, Skyrmions have advantages over the conventional domain walls in metallic ferromagnets. The realization and electrical detection of ground state isolated Skyrmions in nanowires would demonstrate the proof-of-concept for utilizing Skyrmions for magnetic storage. The broader impact of the project includes that the success of the project will open up new design concepts for magnetic memory and spintronic devices with low-power, enhanced performance, and mass data storage, therefore bringing broad technological impacts. Education and outreach is closely integrated with active research in this project by recruiting underrepresented undergraduate students to participate in nanotechnology research in spintronic materials and devices, and by further developing a nanotechnology workshop for high school students and teachers. Used computer hard drives and integrated circuit chips will be examined during the workshop to allow students to learn basic concepts in spintronics and nanoelectrics and how they connect to digital gadgets, encouraging their interest in science and engineering.

该项目旨在利用硅化物和锗化物纳米线中的手性磁性斯格明子磁畴用于磁性数据存储应用。斯格明子是一种新型的奇异磁序，其中电子自旋定向形成拓扑上非平凡的漩涡状结构。最近在非中心对称 B20 单硅化物（MnSi、Fe1-xCoxSi）或单锗化物 (FeGe) 中发现了它们。斯格明子可以被认为是磁结、类粒子域，对磁场和温度的小扰动稳定，并且不会强烈固定在晶格或杂质上。由于自旋矩相互作用，斯格明子与电流强烈耦合，因此需要低得多的临界电流密度来驱动斯格明子域的运动。斯格明子为实现自旋电子和磁性存储器件设计提供了新的机会。 此外，由于斯格明子相在受限的一维几何结构中的稳定性，纳米线提供了一种在没有外加磁场的情况下实现、检测和操纵孤立的手性磁性斯格明子的理想系统。 基于在金属硅化物和锗化物纳米线生长方面的进展以及使用纳米线构建块进行自旋电子器件研究的专业知识，PI 计划观察、测量和操纵非中心对称 B20 硅化物（例如 Fe1-xCoxSi）纳米线中的手性斯格明子和锰硅。具体来说，通过与东京大学的国际合作，洛伦兹透射电子显微镜将用于可视化这些纳米线中的斯格明子。此外，斯格明子引起的拓扑霍尔效应将在纳米线中进行电学测量。最后，斯格明子的新兴动力学及其运动将在纳米线电气设备中进行研究。智力优势：该研究项目通过将现有纳米线材料与仔细的设备和物理研究相结合，首次提供了观察和电检测斯格明子运动的机会。与薄膜和块状样品相比，纳米线几何结构具有多种优势，并且更适合展示这种新颖的现象，因此纳米线可以作为模型材料平台，将斯格明子的研究从基础物理扩展到更多的应用设备工作和最终应用。由于其独特而优越的性能，斯格明子比金属铁磁体中的传统畴壁具有优势。纳米线中基态隔离斯格明子的实现和电检测将证明利用斯格明子进行磁存储的概念验证。该项目更广泛的影响包括，该项目的成功将为低功耗、增强性能和海量数据存储的磁存储器和自旋电子器件开辟新的设计理念，从而带来广泛的技术影响。教育和推广与该项目的积极研究紧密结合，招募代表性不足的本科生参与自旋电子材料和器件的纳米技术研究，并进一步为高中生和教师举办纳米技术研讨会。研讨会期间将检查使用过的计算机硬盘和集成电路芯片，让学生学习自旋电子学和纳米电学的基本概念以及它们如何连接到数字设备，从而激发他们对科学和工程的兴趣。