CAREER: Spin-Torque Oscillator Arrays

研究了多层巨磁阻（GMR）和隧道磁阻（TMR）自旋力矩振荡器（STO）阵列中静磁自旋波的产生、传播、相互作用和吸收。随着最近自旋转矩传递和自持续振荡器的演示，一类具有极端可调性和优异射频性能潜力的新型振荡器出现了。然而，最近的结果表明，这些新器件的潜力受到单个器件的大相位噪声的限制，这是由于单个器件中存储的能量很少。一个潜在的解决方案是在一个大阵列中锁相许多sto。本研究的重点是多器件阵列中STO-STO相互作用的基础科学，旨在为STO振荡器的可控、可扩展阵列奠定基础。具体而言，本研究计划重点研究自旋波STO相互作用的三个基础科学：1)多层STO堆栈上的静磁表面波动力学研究；2)STO的静磁表面波激发发射研究；3)STO-STO相互作用的空间依赖性和标度。智力优势：本研究将发展关于多层GMR/TMR堆叠中静磁自旋波传播的基础知识，例如波数、衰减、方向性对各种参数的依赖，以及将自旋波能量传递到相邻sto的最佳膜结构。此外，对自旋波相互作用的研究将对单个自旋波的发射效率、单个自旋波对自旋波的散射/吸收/放大、自旋波场下自旋波的频率拉效应以及受激粒子与连续平面波的非线性相互作用有新的认识。更广泛的影响：本研究将开发STO阵列，具有低相位噪声振荡器和频谱敏捷RF系统的高可调性。与这些研究项目相结合的是开发新的跨学科课程的综合努力，这些课程侧重于器件物理及其应用的基础，创建虚拟实验室，使全球的学生能够探索这些基本概念，并向当地社区的小学和高中学生介绍令人兴奋的磁学和电子学领域。此外，一个综合的研究和教育计划将为当地社区和全球的学生提供直接访问，通过网络部署的虚拟实验室和教育教程来研究纳米级设备的基础知识。教育方面的努力将侧重于通过虚拟实验室为学生开发体验式学习活动，使学生通过实验和探索来学习概念，补充传统的以讲座为基础的教育方法。

This research investigates magnetostatic spin-wave generation, propagation, interaction and absorption in multi-layer Giant magnetoresistance (GMR) and Tunnel magnetoresistance (TMR) spin-torque oscillator (STO) arrays. With the recent demonstration of spin-torque transfer and self-sustained oscillators, a new class of oscillator has emerged with extreme tunability and potential for excellent RF performance. Recent results have shown, however, that the potential of these new devices is limited by the large phase noise of individual devices due to the small amount of energy stored in a single device. A potential solution is the phase-locking of many STOs in a large array. This research focuses on the fundamental science of STO-STO interaction in multi-device arrays with the goal of laying the foundation for controllable, scalable arrays of STO oscillators. Specifically, this research proposal focuses on three tasks investigating fundamental science of spin-wave STO interaction: 1) Study of magnetostatic surface wave dynamics on multi-layer STO stacks, 2) Study of magnetostatic surface wave stimulated emission by an STO, and 3) Spatial dependence and scaling of STO-STO interactions. Intellectual merit: This research will develop fundamental knowledge about magnetostatic spin wave propagation in multi-layer GMR/TMR stacks such as dependence of wavenumber, decay, directionality on various parameters and also the best possible film configuration for transferring spin wave energy to adjacent STOs. In addition the proposed study on STO-wave interaction will develop new understanding about spin wave emission efficiency of a single STO, spin wave scattering/absorption/amplification by a single STO, frequency pulling effect of a STO under spin wave field as well as non-linear interaction of an excited particle (STO) with a continuous plane wave. Broader impacts: This research will develop STO arrays, with low phase noise oscillators and high tunability for spectrum-agile RF systems. Combined with these research programs is an integrated effort for the development of new interdisciplinary courses that focus on the fundamentals of device physics and their applications, the creation of virtual laboratories that enable students around the globe to explore these fundamental concepts, and the introduction of elementary and high school students in local communities to the exciting field of magnetics and electronics. Furthermore, an integrated research and educational program will provide direct access for students, in local communities and around the globe, to investigate fundamentals of nanoscale devices through web-deployed virtual laboratories and educational tutorials. The educational efforts will focus on developing experiential learning activities for students via virtual labs to enable students to learn concepts through experimentation and exploration, complimenting traditional lecture based educational methods.