GOALI: Spin-Transfer in Magnetic Nanostructures

****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，旨在进一步了解自旋转移的物理学和自旋转移在高性能器件中的应用。自旋转移是一种机制，通过自旋极化电流可以扭转纳米磁体的磁取向，并引起磁激励，如自旋波。这是一项令人兴奋的发展，很可能使磁性信息处理和存储方面取得巨大进步。这是因为自旋转移提供了一种机制，可以快速逆转具有大磁各向异性的纳米磁体的磁化，否则需要巨大的局部磁场-这是增加磁信息存储密度的关键成就。然而，随着纳米磁铁尺寸的减小，它们的磁矩变得更容易由于与热和电噪声相关的随机力而反转。因此，理解噪声对自旋转移驱动的磁化动力学的影响是至关重要的。该项目将通过对受自旋电流激发的单个纳米磁体的实验研究，包括利用铁磁绝缘体激发产生的自旋电流的新研究方向，促进对自旋转移物理学的理解。这些实验研究将在对存在自旋传递转矩的噪声诱导跃迁的理论分析的指导下进行。理论分析将集中于非梯度确定性动力学与随机力相互作用所产生的新现象。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中获益。****非技术摘要****该项目汇集了来自纽约大学和IBM的领先研究人员，旨在进一步了解和应用纳米级磁性器件和材料。磁性纳米结构在信息处理领域的应用最为广泛。随着世界范围内对数据处理和存储的需求不断增加，这在美国是一个巨大的行业，正在迅速发展。人们已经发现，在微型磁性器件中，直流电可以通过一种称为自旋转移的机制来改变磁化方向。这是一项令人兴奋的发展，可能会使磁性信息处理和存储方面取得巨大进步。关于电流和磁化之间相互作用的本质，本项目将通过使用独特的高频测量技术研究由自旋电流激发的单个磁性纳米结构来解决一些重要和基本的问题。这项研究将与磁学研究前沿领域年轻科学家的培训相结合。参与的研究生和本科生将通过学术界和工业界的互动以及纽约大学和IBM之间的交流而获益。通过接触工业环境中的各种观点、专业知识和技术，他们的教育将得到丰富。高中生也将参与这项研究。

****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 of the physics of spin-transfer and applications of spin-transfer to high performance devices. Spin-transfer is a mechanism by which a spin-polarized current can reverse the magnetic orientation of a nanomagnet and induce magnetic excitations such as spin-waves. This is an exciting development that will very likely enable dramatic improvements in magnetic information processing and storage. This is because spin-transfer offers a mechanism for rapidly reversing the magnetization of nanomagnets with large magnetic anisotropy that would otherwise require huge local magnetic fields -an achievement critical to increasing magnetic information storage density. However, as nanomagnets are reduced in size their magnetic moments become more susceptible to reversal due to random forces associated with thermal and electrical noise. An understanding of the effects of noise on spin-transfer driven magnetization dynamics is thus critical. This project will advance understanding of spin-transfer physics through experimental studies of individual nanomagnets excited by spin-currents, including a new research direction that will use spin-currents generated through excitation of ferromagnetic insulators. These experimental studies will be conducted in concert and guided by a theoretical analysis of noise-induced transitions in the presence of spin-transfer torques. The theoretical analysis will focus on new phenomena generated by the interaction of a nongradient deterministic dynamics with random forces. Graduate and undergraduate students involved in this collaboration will gain by interactions between academia and industry.****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 information processing. This is a huge industry in the United States that is growing rapidly, with the ever-increasing worldwide demands for data processing and storage. It has been discovered that in miniature magnetic devices a direct electrical current can switch the direction of magnetization by a mechanism known as spin-transfer. This is an exciting development that may enable dramatic improvements in magnetic information processing and storage. There are important and fundamental questions about the nature of the interaction between the current and magnetization that this project will address through studies of individual magnetic nanostructures excited by spin-currents using unique high frequency measurement techniques. This research will be integrated with the training of young scientists in this forefront area of magnetism research. Participating graduate and undergraduate students will gain by interactions between academia and industry and through exchanges between NYU and IBM. Their education will be enriched through exposure to a variety of perspectives, expertise and techniques present in an industrial setting. High school students will also participate in this research.