Long-Range Spin Transport in Light-Metal Alloys

非技术摘要磁性材料在技术上无处不在，从我们周围的永久磁铁到能够实现云数据存储的强大硬盘驱动器中经过精确设计的磁性材料。自旋电子学是支撑这类技术的科学领域，它基于对电子自旋属性的控制。自旋电子学领域的一个主要限制是，即使是在微小距离内移动电子自旋也是非常具有挑战性的；这样做的能力将释放非凡的技术潜力，包括大幅降低计算机的功耗。这个项目正是解决了这一挑战，不仅寻求电子自旋的长距离传输，而且还在以简单金属为基础的工业相关材料中实现了这一点。除了促进对这一过程的物理学的基本理解外，通过这项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(从而为美国电子设备部门的熟练劳动力做出贡献)，以及通过与明尼苏达州科学博物馆合作向公众宣传，正在产生更广泛的影响。自旋电子学中的技术摘要，通过接口注入自旋，以及随后的传输，是许多设备功能的中心。这样的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远程自旋传输，这可能实现诸如自旋互连和自旋累积传感器等变革性功能。关于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，尽管金属自旋电子学已经建立得很好，并且服从于技术。这是因为传统的多晶非磁性金属薄膜的自旋扩散长度通常只有100‘S nm，受缺陷引起的自旋弛豫的限制。该项目寻求直接缓解这一限制。通过合理设计的轻金属合金的新应用，人们正在寻求非磁性金属薄膜中自旋扩散长度的数量级增长，使用理论指导的电子结构成分调整和能带填充来可控地抑制自旋弛豫。除了促进对相关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，以及通过与明尼苏达州科学博物馆合作向公众推广，正在取得更广泛的影响。该奖项反映了NSF的法定使命，并通过使用基金会的智力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 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.