Spin-Transfer Nano-Oscillators

Published

January 7, 2013

Author(s)

Stephen E. Russek, Ranko R. Heindl, Thomas Cecil, William H. Rippard

Abstract

Spin transfer nano-oscillators are small multilayer magnetic devices that undergo microwave oscillations and output a microwave voltage when a bias current is applied. The oscillation frequency is tunable, over a range of 0.5 GHz to 225 GHz, by varying the bias current and applied magnetic field. The oscillators utilize spin polarized currents generated by electrons passing through a thin ferromagnetic layer to transport angular moment and apply a torque to a downstream magnetic layer that is free to rotate in response to the spin torque. The devices are similar to giant magnetoresistance (GMR) and tunneling magnetoresistance (TMR) devices that are being developed for magnetic recording sensors and magnetic random access memory. Resistance variations due to GMR and TMR effects are utilized, in conjunction with the spin torque induced oscillations, to produce a microwave output voltage. Here, we present a tutorial that describes operating principles, fabrication, and application of these devices.

Citation

Handbook of Nanophysics

Issue

6

Pub Type

Encyclopedias

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DOI Link

Keywords

Spin transfer nano-oscillators, STNO, spin transfer, magnetic devices, magnetic tunnel junctions, spin valves, microwave oscillators

Citation

Russek, S. , Heindl, R. , Cecil, T. and Rippard, W. (2013), Spin-Transfer Nano-Oscillators, Handbook of Nanophysics, [online], https://doi.org/10.1039/C2NR33407K (Accessed May 23, 2025)