Long-Range Spin Transport in Light-Metal Alloys

磁性材料在技术中无处不在，从我们周围的永磁体到功能强大的硬盘驱动器中精确设计的磁性材料，使云数据存储成为可能。自旋电子学是支撑这种技术的科学领域，其基础是控制电子的性质，即自旋。自旋电子学领域的一个主要限制是，即使在微观距离上移动电子自旋也非常具有挑战性;这样做的能力将释放非凡的技术潜力，包括大规模降低计算机的功耗。该项目正是为了解决这一挑战，不仅寻求电子自旋的远程传输，而且在基于简单金属的工业相关材料中进行。除了推进对这一过程的物理学的基本理解外，通过工作的高技术相关性，通过对研究生和本科生的教育和培训（从而为电子设备行业的熟练美国劳动力做出贡献），以及通过与明尼苏达科学博物馆一起向公众宣传，正在实现更广泛的影响。 技术摘要在自旋电子学中，跨界面的自旋注入及其随后的传输是许多设备功能的核心。这些设备已经对数据存储和处理产生了巨大影响，并有进一步发展的潜力。一个特别令人兴奋的前景是通过材料的长距离自旋输运，这可以实现诸如自旋互连和自旋累积传感器的变革能力。尽管金属自旋电子学已经很成熟，而且技术上也很可靠，但对长程自旋输运的基础研究几乎完全集中在半导体和绝缘体上。这是因为常规多晶非磁性金属薄膜中的自旋扩散长度通常仅为100纳米，受到缺陷诱导的自旋弛豫的限制。本项目旨在直接缓解这一限制。通过合理设计的轻金属合金的新应用，使用理论指导的电子结构和能带填充的成分调整来可控地抑制自旋弛豫，正在寻求在金属薄膜中自旋扩散长度的数量级增加。除了促进对相关物理学的基本理解外，还通过工作的高技术相关性，通过对研究生和本科生的教育和培训，该奖项反映了NSF的法定使命，并通过使用基金会的知识产权进行评估，被认为值得支持。优点和更广泛的影响审查标准。

Non-Technical AbstractMagnetic materials are ubiquitous in technology, from the permanent magnets all around us to the precisely engineered magnetic materials in the powerful hard disk drives that enable cloud data storage. Spintronics is the scientific field that underpins such technologies, based on control of the property of electrons known as spin. One major limitation in the field of spintronics is that is very challenging to move electron spins over even microscopic distances; the ability to do so would unlock extraordinary technological potential, including massively reducing the power consumption of computers. This project is addressing exactly this challenge, not only seeking long-range transport of electron spins, but doing so in industrially-relevant materials based on simple metals. In addition to advancing the fundamental understanding of the physics of this process, broader impacts are being achieved through the high technological relevance of the work, through education and training of graduate and undergraduate students (thus contributing to a skilled US workforce in the electronic device sector), and through outreach to the public in conjunction with the Science Museum of Minnesota. Technical Abstract In spintronics, injection of spins across interfaces, and their subsequent transport, is central to the function of many devices. Such devices have already massively impacted data storage and processing, with potential for further advances. One particularly exciting prospect is long-range spin transport through materials, which could realize transformative capabilities such as spin interconnects and spin accumulation sensors. Fundamental research on long-range spin transport has focused almost entirely on semiconductors and insulators, despite metallic spintronics being well-established and amenable to technology. This is because spin diffusion lengths in conventional polycrystalline non-magnetic metallic thin films are typically only 100’s of nm, limited by defect-induced spin relaxation. This project seeks to directly alleviate this limitation. Orders-of-magnitude increases in spin diffusion lengths in nonmagnetic metallic thin films are being sought via novel application of rationally-designed light-metal alloys, using theory-guided compositional tuning of electronic structure and band filling to controllably suppress spin relaxation. In addition to advancing the fundamental understanding of the relevant physics, broader impacts are being achieved through the high technological relevance of the work, through education and training of graduate and undergraduate students, and through outreach to the public in conjunction with the Science Museum of Minnesota.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.