Understanding Spin Diffusion Lengths in Metals and Oxides

了解金属和氧化物中的自旋扩散长度

基本信息

批准号：
1807124
负责人：
Christopher Leighton
金额：
$ 40.66万
依托单位：
University of Minnesota-Twin Cities
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2018
资助国家：
美国
起止时间：
2018-08-01 至 2021-11-30
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1807124&HistoricalAwards=false
关键词：
Understanding Spin Diffusion Lengths Metals

项目摘要

Non-technical abstract:High performance magnetic devices are ubiquitous in our society, the magnetic hard disk drives that power cloud data storage serving as one example. Underpinning technological advancement in this area is the ongoing progress in fundamental understanding of magnetism and magnetic materials. In this project, a fundamental problem relevant to "spin electronics" is being tackled, specifically how electron spins relax after being pumped from magnetic to non-magnetic materials. This is a poorly understood issue in magnetism, despite many scientific efforts and high importance for next generation devices. In this work, a particular type of nanomagnetic device is being used to understand, quantitatively, and for the first time, how specific materials defects control the relaxation of spins. In addition to advancing basic scientific knowledge, broader impact is being achieved through societal benefits from device applications, through education of students, and through outreach to the public. The latter involves collaboration with the Science Museum of Minnesota, developing exhibits and performances on the science of materials in our everyday lives, thus raising awareness of the role of materials research in our society.Technical abstract:Central to many spintronic phenomena and devices is the flow of a pure spin current, or a spin-polarized charge current, in a non-magnetic metal. A fundamental question in such a situation is over what distance does a non-equilibrium spin population relax in a non-magnetic metal, or: what is the spin diffusion length? Remarkably, while the basic mechanism governing metallic spin relaxation, the Elliot-Yafet mechanism, is known, there remain massive gaps in our understanding of this process. The individual effects of specific defects remain unknown, preventing quantitative or predictive understanding of spin transport. Addressing this problem, with its obvious technological relevance, would constitute a transformative advance. The essence of this project is to use non-local lateral spin valves to determine spin diffusion lengths in a variety of conventional and oxide-based metals. Elemental metals such as Al are being studied to separately quantify spin relaxation due to phonons, impurities, grain boundaries, surfaces, and interfaces, thus determining Elliott-Yafet constants for each defect. Metallic perovskite oxides are also being studied. These materials offer tremendous potential for spintronics, although an understanding of their spin diffusion lengths remains elusive. A progression from conventional metal-based devices to perovskite metals is being followed in this research, providing the first understanding of spin diffusion lengths in oxide ferromagnets and non-magnetic metals, a critical step in the development of oxide spintronics.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

非技术摘要：高性能磁性设备在我们的社会中无处不在，磁性硬盘驱动电源云数据存储作为一个例子。该领域的技术进步的基础是对磁性和磁性材料的基本理解的持续进展。在这个项目中，正在解决与“自旋电子”相关的基本问题，特别是电子从磁性泵送到非磁性材料后如何放松。尽管有许多科学的努力和对下一代设备的重要性，但这在磁性中是一个知之甚少的问题。在这项工作中，一种特定类型的纳米磁性装置被用来理解，定量，这是第一次，特定材料缺陷如何控制旋转的松弛。除了促进基本科学知识外，还通过设备应用，学生的教育以及向公众推出的社会利益来实现更广泛的影响。后者涉及与明尼苏达州科学博物馆的合作，在我们的日常生活中开发了有关材料科学的展览和表演，从而提高了对材料研究在我们社会中的作用的认识。技术摘要：许多旋转现象和设备的核心是纯旋转电流的流动，或者是旋转电流的流动，或者是一种旋转的电荷电流，在非杂种金属中。在这种情况下，一个基本问题是非平衡自旋种群在非磁性金属中放松的距离，或者：自旋扩散长度是多少？值得注意的是，尽管众所周知的艾略特（Elliot-Yaft）机制的基本机制（艾略特（Elliot-Yafet）机制）在我们对这一过程的理解中仍然存在巨大差距。特定缺陷的个体影响仍然未知，以防止对旋转转运的定量或预测理解。以其明显的技术相关性解决这个问题将构成变革性的进步。该项目的本质是使用非本地侧向自旋阀来确定各种常规和氧化物金属中的自旋扩散长度。正在研究元素金属，以分别量化由于声子，杂质，晶界，表面和界面而引起的自旋松弛，从而确定每个缺陷的Elliott-yafet常数。还研究了金属钙钛矿氧化物。这些材料为旋转基质提供了巨大的潜力，尽管对它们的自旋扩散长度的理解仍然难以捉摸。这项研究正在遵循从传统金属设备到钙钛矿金属的进展，这是对氧化物铁磁体和非磁性金属中自旋扩散长度的首次理解，这是氧化物旋转型的发展的关键一步，这是NSF的法定任务，反映了通过评估范围的Intellitia intiftial intiftial and Foundation and Foundation的支持。