A Spin Torque Oscillator Maser Device Enabled by Spin-Microwave Photon Coupling

Massachusetts Institute Of Technology, Cambridge MA

Investigators

Abstract

Devices that can generated signals in the microwave frequency range are vital for now a days for telecommunication, radar and quantum computing technologies. There is a critical need for compact and high-performance devices that can be easily combined with other classical or quantum circuit. This proposal proposes to explore the possibility of realizing a new microwave source device that will have superior performance over existing ones, by applying new mechanisms resulting from the interactions between microwave signal and magnetic materials. The proposed research, if successful, will not only lead to advancement in the scientific areas, but also have educational impact by developing course modules that will enhance students’ understanding on quantum science by attracting students at all levels, particularly from socio-economically disadvantaged groups, into the study of applied physics and electronic engineering. Outreach activities include inspiring broad public awareness in the exciting opportunities in magnetic device domains. The approach used in the project is based on the phenomenon of spin torque oscillator, which is one promising technique for realizing on-chip microwave sources, detectors, and neuromorphic computing devices. Existing spin torque oscillators suffer from challenges in low output power, broad linewidth as well as the requirement for complicated external supporting circuits, which greatly limits their practical applications. In this project, to overcome these difficulties, a new approach for realizing coherent magnetic self-oscillation in a large area ferromagnetic thin film by placing a spin torque oscillator into a microwave resonator is conceived. The mutual interactions between the magnet and microwave resonator will lead to a coupling between their oscillation dynamics, which will further result in macroscopic phase coherence in magnetic free layer with very large area. By fabricating the proposed device structures and testing on the microwave input-output relationship, the proposed device structure will not only result in a novel coherent, high power, on-chip microwave source, but also enrich people’s understanding on spin dynamics and the coupling physics between magnets and microwave. 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.