SGER: Spin-Transfer-Torque Devices Based on Magnetostatically-Coupled Sub-50nm Structures

技术方面：在理解纳米级磁性结构中的自旋传递转矩（STT）效应方面取得了重大进展。STT能够通过自旋极化电流来切换磁性结构的磁态，在器件简单和功耗方面具有优势。大多数STT研究都是针对磁性随机存取存储器的发展。然而，STT的可能应用范围要比这广泛得多，包括例如可编程逻辑和存储设备的组合。这一领域的进展是基于新磁性材料的开发和对加工条件、成分、微观结构和图案对材料磁性能的影响的理解。本次SGER奖的智力价值在于通过构建功能磁性纳米结构，研究具有不同层序和组成的金属多层纳米结构中的STT效应。PI将设计一个将STT效应与静磁相互作用相结合的设备，以显示如何在单个磁性设备内写入，传输和处理数据。选择用于图像化的多层堆叠将包含由非磁性金属或绝缘体分离的自由磁性层与合成反铁磁钉住层。通过考虑电池形状、多层堆叠、图像化条件和微观结构的影响，优化STT操作所需的临界电流密度。重点将放在磁性多层中的金属合金和层序的选择如何影响器件的性能，以及由此产生的关于STT机制的信息。非技术：更广泛的影响是培养磁性纳米结构和STT领域的研究人员和本科生。研究人员将与2 ？4名本科生参与项目。本科生将通过本科研究机会（UROP）计划，或作为高级论文项目学生，或通过REU计划参加。此外，研究人员和PI计划在夏季RET项目期间与至少一名教师合作，并将该项目的研究结果纳入研究生和本科生课程。

TECHNICAL: There has been significant progress in the understanding of spin-transfer torque (STT) effects in nanoscale magnetic structures. STT is capable of switching the magnetic state of a magnetic structure by the passage of a spin-polarized current, offering advantages in terms of device simplicity and power consumption. Most STT research has been directed towards the development of magnetic random access memories. However, the possible applications of STT are much wider than this, including for example combined programmable logic and memory devices. Progress in this field is based on the development of new magnetic materials and an understanding of the influence of the processing conditions, composition, microstructure and patterning on the magnetic properties of the materials. The intellectual merit of this SGER award is to investigate STT effects in metal multilayer nanostructures with different layer sequences and compositions, through building functional magnetic nanostructures. PI will design a device that will combine STT effects with magnetostatic interactions to show how data can be written, transmitted, and processed within a single magnetic device. Multilayer stacks chosen for patterning will contain a free magnetic layer separated from a synthetic-antiferromagnet pinned layer by a non-magnetic metal or an insulator. The critical current densities required for STT operation will be optimized by considering the influence of the cell shape, multilayer stack, patterning conditions and microstructure. The focus will be on how the choice of metal alloys and layer sequence in the magnetic multilayer affects the performance of the device, and the information this yields about the mechanism of STT. NON-TECHNICAL: The broader impacts are to train a researcher and undergraduate students in the field of magnetic nanostructures and STT. The researcher will work with 2 ? 4 undergraduates during the course of the project. The undergraduates will participate through the undergraduate research opportunities (UROP) program, or as senior thesis project students, or through a REU program. In addition, the researcher and the PI plan to work with at least one teacher during a summer RET program, and incorporate findings from the project into graduate and undergraduate classes.