Electrical control of nanoscale magnetic devices.

纳米磁学是科学中最活跃的领域之一，它为我们提供了广泛的基础科学问题以及重要的新兴技术。许多基于自旋的器件仍处于起步阶段，对潜在材料和电子特性及其对器件性能的影响的透彻理解对于所有未来的应用都是至关重要的。提出的研究研究相对未开发和新兴领域的电场控制的金属磁系统和利用这些效应在新的自旋基器件。该提案将解决电场控制过渡金属及其合金和化合物的固有磁性。研究的材料参数包括磁性过渡金属体系中的磁矩密度、磁各向异性、居里温度和非绝热自旋传递参数。所研究的所有系统将被选择使它们的磁性排序接近或高于室温。因为这些材料是导电的，电场（及其对磁性的影响）被限制在近表面区域；因此，本研究将集中在薄膜和异质结构器件上，这些器件的表面会显著影响磁性能。这一提议的智力价值在于，它有望在纳米尺度上对电场对流动磁性的修饰获得基本的、预测性的理解。通过结合薄膜合成和器件制造技术、器件结构中的输运和磁光测量以及先进的表征技术，将获得完整的数据集。这些结果将测试金属系统中磁电耦合的现有模型，并预计在本研究中将出现有趣和意想不到的新磁现象。这项研究的广泛影响将是技术和教育两方面的。这项研究将在纳米尺度上解决磁性和自旋输运的基本问题，并在材料合成和表征、器件制造、纳米科学和纳米技术等重要领域培养本科生和研究生。了解电场对磁性的影响将对理解当前磁性隧道装置的性能，到评估未来基于自旋的电子设备的电气控制潜力产生广泛的影响。变革的目标是为下一代节能、超快和超小型磁电子设备提供科学基础。

Nanomagnetism is one of the most active areas in science that presents us with a wide range of fundamental scientific problems as well as important and emerging technologies. Many spin-based devices are still in their infancy and a thorough understanding of the underlying materials and electronic properties and their effect on device performance will be essential for all future applications. The proposed research studies the relatively unexplored and emerging field of electric field control of metallic magnetic systems and exploits these effects in novel spin-based devices. The proposal will address the electric-field control of the intrinsic magnetic properties of transition metals and their alloys and compounds. The materials parameters to be studied include the magnetic moment density, magnetic anisotropy, Curie temperature and non-adiabatic spin-transfer parameter in magnetic transition-metal systems. All systems studied will be chosen such that they magnetically order near or above room temperature. Because these materials are conducting, the electric field (and its affect on magnetism) is confined to the near surface region; therefore this research will focus on thin films and heterostructured devices where the surfaces can dramatically affect the magnetic properties. The intellectual merit of the proposal stems from the prospect of achieving a fundamental and predictive understanding of the electric-field modification of itinerant magnetism at the nanoscale. By combining skills in thin film synthesis and device fabrication, transport and magneto-optical measurements in device structures, and advanced characterization techniques, a complete data set will be obtained. These results will test current models of magneto-electric coupling in metallic systems and it is anticipated that interesting and unexpected new magnetic phenomena will emerge in this study. The broader impact of the research will be both technical and educational. This research will address fundamental issues of magnetism and spin transport at the nanoscale and train undergraduate and graduate students in important areas of materials synthesis and characterization, device fabrication, nano-science, and nano-technology. An understanding of electric field effects on magnetism will have broad ranging impact from understanding the performance of current magnetic tunneling devices, to assessing the potential of electrical control in future spin-based electronics. The transformative goal is to provide the scientific underpinnings of next generation energy efficient, ultrafast, and ultrasmall magneto-electronic devices.