ACT/SGER: Enhancement of Magnetically-Transduced Surface Acoustic Wave Sensors

Cornell University, Ithaca NY

Investigators

Abstract

This project aims at demonstrating a potential breakthrough concept in remote chemical and biological sensor systems. The approach is to explore the possibility of obtaining enhanced magnetomechanical coupling when the resonant precession frequency of individual magnetic moments in a ferromagnetic thin film is identical to the surface acoustic wave resonant frequency of a magnetostrictive transducer. If feasible this would strongly enhance the viability of magnetically-transduced surface acoustic wave devices for remote detection of chemical/biological threats. Fabrication of such devices is compatible with conventional integrated circuit processing, so device arrays could be integrated with transistor electronics on a single chip to make a versatile, inexpensive system for remote chemical detection. The interaction between resonant precession (Ferromagnetic Resonance) and acoustic resonance will be characterized by measuring the ultrahigh-frequency (UHF) complex permeability of magnetic stripe structures with a fixed acoustic resonance frequency, varying the precession resonance with an external magnetic field. The structures, materials, and fields used will result in resonances in the range 1 MHz - 1 GHz. The coupling of resonant precession with a resonant surface acoustic wave has not been explored previously, and in addition to the sensor application, may lead to new insights into UHF properties of magnetic materials, particularly magnetic damping. %%% An important feature of the project is education and training, with emphasis on integration of research and education. The graduate student supported by this funding will establish a foundation for developing and characterizing novel magnetic devices for chemical/biological sensing applications. In addition, undergraduates will work in the PI's laboratory on projects related to this research effort and gain their first experience of performing research in a state-of-the-art environment. Additionally, the PI will participate in outreach activities via the NSF-funded Cornell Center for Material Research, as well as in other activities sponsored by the College of Engineering, such as the Cornell University Research In Engineering (CURIE) Academy, a program offering high-school girls the opportunity to explore careers in Engineering. This award is supported jointly by the NSF and the Intelligence Community. The Approaches to Combat Terrorism (ACT) Program in the Directorate for Mathematics and Physical Sciences supports new concepts in basic research and workforce development with the potential to contribute to national security.