Steady-State and Dynamical Measurements of Spin-Dependent Tunneling via Discrete Quantum States

通过离散量子态对自旋相关隧道进行稳态和动态测量

• 批准号: 0605742
• 负责人: Daniel Ralph
• 金额: --
• 依托单位: Cornell University
• 依托单位国家: 美国
• 项目类别: Continuing grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-08-15 至 2011-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0605742&HistoricalAwards=false
• 关键词: Steady; State; Dynamical; Measurements; Spin

Non-technical:All electrons carry with them an intrinsic spin, as well as electrical charge. It is therefore possible to control the flow of electrons by acting on their spin (a strategy known as "spintronics") rather than by using conventional techniques which manipulate their charge. This project will investigate the fundamental mechanisms which affect the dynamics of electron spins in nanometer-scale structures and which cause the motion of electrons within these structures to depend on their spin orientation. The research to be pursued will involve comparing the properties of non-magnetic quantum states, few-spin states, and fully-magnetic high-spin states, and how spins can be excited, precess, and relax in these different materials. The work will contribute to the rapid progress now underway to develop and optimize practical spin-based devices such as magnetic field sensors (now used in disk drives) and non-volatile magnetic random access memories. The graduate and undergraduate students to be trained on the project will gain broad expertise in nanofabrication and characterization techniques, as well as skills in presenting their work verbally and in writing, and will be well-prepared to be future leaders in nanotechnology.Technical:This project will utilize electron-tunneling measure-ments of quantized energy levels in nanometer-scale samples to study spin transport in magnetic devices and the dynamics of spin states. By comparing the properties of non-magnetic quantum states, few-spin states, and fully-magnetic high-spin states, the work will seek to characterize the fundamental mechanisms affecting spin-dependent tunneling, spin accumulation and relaxation, and the emergence of collective magnetic properties as a function of increasing exchange-interaction strength. The project will investigate not only steady-state electrical properties, but will also develop experimental techniques to measure the dynamical properties of individual nanoscale magnets as they undergo precession and switching in response to magnetic fields or current-induced torques. This work will be of practical relevance for optimizing magnetic tunnel-junction devices used as sensors in disk drives and for understanding magnetic excitations produced by spin-transfer torques which under investigation for use in non-volatile magnetic random access memory. The graduate and undergraduate students to be trained on the project will gain broad expertise in nanofabrication and characterization techniques, as well as skills in presenting their work verbally and in writing, and will be well-prepared to be future leaders in nanotechnology.

非技术性：所有电子都带有固有的自旋和电荷。 因此，可以通过作用于电子的自旋（一种称为“自旋电子学”的策略）来控制电子的流动，而不是使用操纵其电荷的传统技术。该项目将研究影响纳米尺度结构中电子自旋动力学的基本机制，以及导致这些结构中电子运动取决于其自旋方向的基本机制。 要追求的研究将涉及比较非磁性量子态，少自旋态和全磁性高自旋态的性质，以及自旋如何在这些不同的材料中被激发，旋进和弛豫。 这项工作将有助于目前正在进行的快速进展，以开发和优化实用的基于自旋的设备，如磁场传感器（现在用于磁盘驱动器）和非易失性磁性随机存取存储器。 研究生和本科生将获得广泛的专业知识，在nanofabstraction和表征技术，以及技能，提出他们的工作口头和书面，并将做好准备，在nanotechnology.Technical未来的领导者：本项目将利用电子隧道测量的量子化能级在纳米尺度的样品，研究自旋输运的磁性器件和自旋态的动力学。通过比较非磁性量子态、少自旋态和全磁性高自旋态的性质，这项工作将试图描述影响自旋相关隧穿、自旋积累和弛豫的基本机制，以及集体磁性的出现作为交换相互作用强度增加的函数。 该项目不仅将研究稳态电特性，还将开发实验技术来测量单个纳米级磁体的动态特性，因为它们响应于磁场或电流感应扭矩而进行进动和切换。 这项工作将是具有实际意义的优化磁隧道结器件作为传感器在磁盘驱动器和了解磁激励所产生的自旋转移扭矩正在调查中使用的非易失性磁性随机存取存储器。接受该项目培训的研究生和本科生将获得纳米制造和表征技术方面的广泛专业知识，以及口头和书面展示工作的技能，并为成为纳米技术未来的领导者做好充分准备。