Spin Torque Nano Oscillators as Potential Terahertz (THz) Communications Devices

Report No. ARL-TR-4807
Authors: Alma E. Wickenden, Chris Fazi, Ben Huebschman, Roger Kaul, Andrew C. Perrella, William H. Rippard, and Matthew R. Pufall
Date/Pages: April 2009; 20 pages
Abstract: In this report, we describe the complex impedance of spin torque nano oscillator (STNO) devices. We determined that the STNO is a nonreactive, real-resistance device with single-valued resistance in the broadband frequency range of 500 MHz to 10 GHz (the limit of our test conditions), and that STNOs do not require an external circuit or conjugate matching to operate in a transmitter configuration. We report the first demonstration of the low-power (250 pW), high-frequency (9 GHz) microwave output from an antenna-coupled discrete 50 nm diameter magnetic STNO radiating through air over a distance of 1 m. Amplitude and frequency modulation of the output radiation was used to transmit information from the STNO through microwave antennas. In addition to our identification of the STNO as a highly unusual broadband component that is frequency agile over at least four octaves of frequency without conjugate matching, the STNO is inherently radiation hard with an extremely low operating voltage (<0.25 V) compared to solid-state electronic devices including field-effect transistors (FETs), impact ionization avalanche transit time (IMPATT) diodes, and Gunn diodes. The present results establish the viability of using this class of nanoelectronic devices for frequency-agile communications applications at high frequencies.
Distribution: Approved for public release
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Last Update / Reviewed: April 1, 2009