Regensburg 2013 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 48: Spin-dependent Transport Phenomena

MA 48.4: Vortrag

Freitag, 15. März 2013, 10:15–10:30, H23

Spin-Hall nano-oscillators — •Henning Ulrichs¹, Sergej Demokritov¹, Vladislav Demidov¹, Dietmar Baither¹, Guido Schmitz¹, Sergei Urazhdin², Vasil Tiberkevich³, and Andrei Slavin³ — ¹University of Muenster, Corrensstrasse 2-4, 48149 Muenster, Germany — ²Emory University, Atlanta, GA 30322, USA — ³Department of Physics, Oakland University, Rochester, MI, USA

Pure spin currents generated by the spin Hall effect have been recently utilized to suppress and enhance thermal magnetic fluctuations in magnetic nanodevices, and to reduce the dynamic damping in magnetic films [1].

Here, we experimentally study nano-devices driven by pure spin currents generated due to the spin Hall effect in a Pt electrode, and locally injected into an extended Permalloy film. By using micro-focus Brillouin light scattering spectroscopy, we demonstrate that above a certain current threshold, our device enters a single-mode coherent auto-oscillation regime [2]. The corresponding strongly-localized dynamic mode with the diameter below 100 nanometers, has characteristics reminiscent of the nonlinear stationary spin-wave "bullet"[3].

Our findings suggest a route for the implementation of novel magnetic nano-oscillators that have significant advantages over conventional spin-torque nano-oscillators (STNOs), whose geometry and structure are limited by the requirement that the spin current is accompanied by the electric current flowing through the ferromagnet.

1. Phys. Rev. Lett. 107, 107204 (2011), 2. Nature Materials 11, 1028 (2012), 3. Phys. Rev. Lett. 95, 237201 (2005)