Collaborative Research: Correlating Device Performance and Interfacial Properties for Weyl Spintronics

合作研究：关联 Weyl 自旋电子学的器件性能和界面特性

• 批准号: 2031871
• 负责人: Axel Hoffmann
• 金额: $ 29.82万
• 依托单位: University of Illinois at Urbana-Champaign
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-09-15 至 2023-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2031871&HistoricalAwards=false
• 关键词: Collaborative; Research; Correlating; Device; Performance

This grant supports research into understanding new mechanisms by which electrical currents can be used to switch the magnetic orientation of thin magnetic layers in devices for data processing and storage. The use of current pulses to alter magnetism is central to the operating principles of a variety of electronic and spintronic devices. However, new materials systems are needed to reduce the power consumption required for magnetic switching and to enable future device scaling. This award supports fundamental research to identify quantum materials known as Weyl semimetals that enable significant improvements in the efficiency of current-induced magnetic switching. The project will characterize a variety of Weyl semimetals for use in magnetic devices with emphasis on understanding how the switching metrics are influenced by the interfacial properties between the Weyl semimetal and the magnetic layer. The project will also identify how Weyl semimetals can be used to enable switching of perpendicular magnets to facilitate emerging device concepts. The insights into how new quantum materials can reduce power consumption in electronic and magnetic devices may lead to new advances in electronics and computing devices, providing broad societal benefit. The students’ research training enabled by this project will serve to advance the U.S. economic interests by providing them with the experimental skill set needed to contribute to the technological sector.This collaborative project will lay the groundwork for low-power spintronic devices through a series of research activities aimed at providing a detailed understanding of spin-orbit torques generated by Weyl semimetals. The charge-to-spin conversion process will be thoroughly characterized at a series of interfaces between Weyl semimetals and ferromagnetic metals to quantify torque efficiencies. The interfacial properties of these same structures will be characterized using resonant x-ray reflectivity, a technique that allows for both the elemental concentration and magnetization to be determined as a function of depth across the interfaces. The correlations between spin-orbit torque efficiency and the composition and magnetic properties of the interfaces will elucidate the roles of intrinsic (Weyl physics) and extrinsic (non-idealities at the interfaces) contributions to the torques. These activities will yield a thorough understanding of spin-orbit torques across real interfaces in device-based structures fabricated using industry-relevant deposition processes. The research will also identify novel spin-orbit torques, including those associated with an out-of-plane spin polarization, enabled by the unique properties of Weyl semimetals and quantify torque metrics relevant for non-volatile magnetic memory devices and thermally driven stochastic oscillators, where the magnetization of the free magnetic layer is controlled via spin-orbit torques. Through these research activities, this project will advance progress toward employing Weyl semimetals in emerging electronic and spintronic device architectures.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.

该基金支持研究了解新的机制，通过这种机制，电流可以用来切换数据处理和存储设备中薄磁性层的磁性取向。使用电流脉冲改变磁性是各种电子和自旋电子器件工作原理的核心。 然而，需要新的材料系统来降低磁开关所需的功耗，并实现未来的器件扩展。该奖项支持基础研究，以确定被称为Weyl半金属的量子材料，这些材料能够显着提高电流感应磁开关的效率。该项目将表征用于磁性器件的各种外尔半金属，重点是了解外尔半金属和磁性层之间的界面特性如何影响开关度量。该项目还将确定Weyl半金属如何用于实现垂直磁体的切换，以促进新兴设备概念。对新量子材料如何降低电子和磁性设备功耗的见解可能会导致电子和计算设备的新进展，从而提供广泛的社会效益。该项目为学生提供的研究培训将通过为他们提供为技术部门做出贡献所需的实验技能来促进美国的经济利益。该合作项目将通过一系列研究活动为低功率自旋电子器件奠定基础，旨在详细了解外尔半金属产生的自旋轨道扭矩。电荷到自旋的转换过程将彻底的特点外尔半金属和铁磁金属之间的一系列接口，以量化扭矩效率。这些相同结构的界面特性将使用共振X射线反射率来表征，该技术允许将元素浓度和磁化强度确定为跨界面的深度的函数。自旋-轨道力矩效率与界面的组成和磁性之间的相关性将阐明内在（Weyl物理）和外在（界面处的非理想性）对力矩的贡献。这些活动将产生一个彻底的理解，自旋轨道扭矩在真实的界面，在器件为基础的结构制造使用行业相关的沉积工艺。该研究还将确定新的自旋轨道扭矩，包括与面外自旋极化相关的扭矩，通过Weyl半金属的独特特性实现，并量化与非易失性磁性存储器设备和热驱动随机振荡器相关的扭矩指标，其中自由磁性层的磁化通过自旋轨道扭矩控制。通过这些研究活动，该项目将推动在新兴电子和自旋电子器件架构中使用外尔半金属的进展。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。