Monolithic Spin-Torque Microwave Diode Spectrograph

This Phase I Small Business Technology Transfer program will simulate and demonstrate the feasibility of a Spin-torque microwave diode spectrograph for real-time determination and monitoring of incident microwave signals. The microwave detection will be performed by a bandwidth encompassing parallel array of nano-patterned magnetic tunnel junctions (MTJs). When an ac current of microwave frequency flows through an MTJ the magnetization of the free layer begins to precess. The MTJ resistance change couples to the ac current resulting in a measurable change in dc voltage. The sensitivity of this dc bias has been shown to be comparable to that of state-of-the-art Schottky diode detection with the advantage that the proposed detector is also frequency selective. In this program we use a combination of micromagnetic modeling, coupled with circuit simulations and expreimental fabrication and analysis of MTJ arrays to develop the best approach to prototyping the spectrograph. Consideration will be given to not just the array, but how the microwave input signal is conditioned and what the output will consist of. This will allow the opportunity to tune the circuit to the MTJs for optimal performance and result in a robust prototype design.