GOALI: Spin-Orbit Torques From Magnetically Ordered Materials and Their Applications

摘要：该项目汇集了来自纽约大学和IBM的顶尖研究人员，旨在进一步了解和应用纳米级磁性器件和材料。磁性纳米结构广泛应用于半导体工业中最先进的技术。这与这样一个事实有关：当用磁性材料存储和处理信息时，可以大大减少能源使用；因为存储在磁性材料中的数据可以在没有电源（或移动设备中的电池）的情况下保留。由于全球对数据处理和存储的需求不断增加，先进的磁性设备形成了美国大型工业的支柱。该项目旨在利用磁性材料本身作为自旋轨道扭矩的来源，发现更有效的磁性信息写入方法。该项目与磁学研究前沿领域年轻科学家的培训相结合。参与此次合作的研究生和本科生将从学术界和工业界的互动中获益，并将通过接触工业环境中的各种观点、专业知识和技术而得到丰富。技术摘要：这个NSF-GOALI项目汇集了来自纽约大学和IBM的纳米磁学领域的领先研究人员，旨在进一步理解和应用自旋电子学。自旋电子学的一个重要和首要的目标是发现和表征产生自旋电流和相关自旋力矩的更有效的方法。最近已经确定自旋轨道相互作用可以在磁层上实现非常有效的电荷-自旋转换和大扭矩。然而，作用在铁磁层上的自旋极化通常局限于层平面，因此在反转平面内磁化层的磁化方面非常有效，但在开关和激发垂直磁化元件的磁化方面却不太有效。本项目研究了铁磁层中与自旋轨道耦合相关的自旋电流及其与非磁体的界面，这些界面有可能产生垂直于层平面极化的自旋电流。研究了多种过渡金属材料和界面的电荷自旋转换效率和响应对称性随磁化角的变化规律。利用时间分辨和空间分辨的磁化动力学探针，揭示垂直磁化薄层和图像化纳米结构中的磁化开关机制，进一步了解自旋传递转矩激发的非线性磁化动力学。参与这项合作的研究生和本科生将从学术界和工业界的互动以及纽约大学和IBM之间的学生交流中获益。他们的教育将通过工业环境中的各种观点、专业知识和技术得到丰富。高中学生也将被鼓励参与这个研究项目。作为该项目的一部分，pi将在纽约大学开发一门关于物理与技术的新课程，目的是向学生介绍“现实世界”（大学之外）的物理。本课程将重点介绍将物理学应用于技术商业化和更广泛地影响社会的技术领域所需的技能，包括磁学和量子信息。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Non-Technical Abstract:This project brings together leading researchers from New York University and IBM with the aim of furthering the understanding and application of nanometer scale magnetic devices and materials. Magnetic nanostructures are widely used in technology with the most advanced applications found in the semiconductor industry. This is associated with the fact that there can be large reductions in energy usage when information is stored and processed with magnetic materials; because data stored in magnetic materials can be retained without power (or a battery in mobile devices). Because of ever-increasing worldwide demands for data processing and storage, advanced magnetic devices form the backbone of huge industries in the United States. This project aims to uncover more efficient means of writing magnetic information using magnetic materials themselves as the source of spin-orbit torques. The project is integrated with the training of young scientists in this forefront area of magnetism research. Graduate and undergraduate students involved in this collaboration will gain by interactions between academia and industry and will be enriched through exposure to a variety of perspectives, expertise and techniques present in an industrial setting. Technical Abstract:This NSF-GOALI project brings together leading researchers in nanomagnetism from New York University and IBM with the aim of furthering the understanding and application of spintronics. An important and overarching goal of spintronics is to discover and characterize more efficient means of generating spin currents and associated spin torques on magnetization. Recently it has been established that spin-orbit interactions enable very efficient charge-to-spin conversion and large torques on magnetic layers. However, the spin polarization that acts on the ferromagnetic layer is typically confined to the layer plane, and thus is very effective at reversing the magnetization of in-plane magnetized layers but far less effective in switching and exciting the magnetization of perpendicularly magnetized elements. This project investigates spin currents associated with spin-orbit coupling in ferromagnetic layers and their interfaces to nonmagnets, which have the potential to generate spin currents polarized perpendicular to the layer planes. The charge-to-spin conversion efficiency and the symmetry of the response are studied for a variety of transition metal materials and interfaces as a function of magnetization angle. Time-resolved and spatially resolved probes of magnetization dynamics are employed to reveal magnetization switching mechanisms in thin perpendicularly magnetized layers and patterned nanostructures to further the understanding of the nonlinear magnetization dynamics excited by spin-transfer torques. Graduate and undergraduate students involved in this collaboration will gain by interactions between academia and industry and through student exchanges between NYU and IBM. Their education will be enriched through the variety of perspectives, expertise and techniques present in an industrial setting. High school students will also be encouraged to participate in this research project. As part of this project the PIs will develop a new course at NYU on Physics and Technology with the goal of introducing students to physics in the “real world” (outside of universities). The course will highlight the skills needed to apply physics to commercialize technologies and impact society more broadly in technological fields, including in magnetism and quantum information.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.