Antiferromagnetic Spin Torque Devices for Terahertz Applications

目的：研制利用电流诱导自旋力矩启动和控制反铁磁体超快自旋动力学的超高速纳米级磁性器件。智力优势：在反铁磁体中，亚晶格矩通过强交换场耦合，导致自旋波模式的频率在1.0-3.0太赫兹范围内，因此，反铁磁体中的自旋动力学在亚皮秒时间尺度上演化。反铁磁体有望将磁性设备的运行速度提高2-3个数量级。该研究旨在开发一种新的纳米级磁性器件，如振荡器和开关，其中电流诱导自旋力矩用于启动和控制反铁磁自旋阀的自旋动力学。这里提出的研究具有变革性，不仅为超高速纳米级器件打开了新的大门，而且对理解基础材料科学和反铁磁体的自旋物理学也有重大贡献。更广泛的影响：拟议的项目将支持康奈尔大学的两名研究生和两名本科生的研究，并为研究生的研究提供丰富的领域。为了吸引大一/大二学生学习相关学科，PI将引入一门新的2-3学时的纳米科学课程。PI和研究生将参与康奈尔大学K-12的推广工作，为高中生开设纳米结构入门研讨会，并提供实验室组件。根据美国国际开发署的一项国际发展项目，PI将帮助在巴基斯坦组织教师培训讲习班。

Objective: Development of very high speed nanoscale magnetic devices in which current induced spin torque is used to initiate and control ultrafast spin dynamics in antiferromagnets. Intellectual Merit: In antiferromagnets the sublattice moments are coupled via strong exchange fields that cause the frequencies of the spin-wave modes to be in the 1.0-3.0 terahertz range, and, consequently, spin dynamics in antiferromagnets evolve on sub-picosecond time-scales. Antiferromagnets offer the promise of increasing the operating speeds of magnetic devices by 2-3 orders of magnitude. The proposed research aims to develop a new family of nanoscale magnetic devices, such as oscillators and switches, in which current induced spin torque is used to initiate and control spin dynamics in antiferromagnetic spin valves. The research proposed here is transformative and would not just open new doors for ultrahigh speed nanoscale devices but also contribute significantly towards the understanding of the fundamental material science and spin physics of antiferromagnets.Broader Impacts: The proposed project will support the research of two graduate students and two undergraduate students at Cornell University and provide a rich set of areas for graduate student research. The PI will introduce a new 2-3 credit hour freshman/sophomore level course related to nanosciences with the goal of attracting freshmen/sophomores to related disciplines. The PI and the graduate students will participate in Cornell's K-12 outreach efforts by developing an introductory workshop on nanostructures, with a laboratory component, for high school students. Under a USAID international development program the PI will help organize teacher training workshops in Pakistan..