Nonlinear Magnetic Dynamics
Group of Prof.Dr. S.O. Demokritov
from left to right: Vladislav Demidov, Sergej Urazhdin (Guest), Agnes Gödde, Henning Ulrichs, Johann Jersch, Alexey Ustinov (Guest), Oleksandr Dzyapko, Patryk Nowik-Boltyk, Sergej Uschakow, Matthias Buchmeier, Eric Edwards, Sergej O. Demokritov
The following bachelor and master theses are available at our group:
- "Time resolved measurements of dynamical magnetic processes"
- "Spin wave excitation through spin polarized current"
- "Optical spectroscopy on magnon Bose-Einstein condensates"
News:
Our paper, called "Magnetic nano-oscillator driven by pure spin current" was published in Nature Materials.
Abstract:
With the advent of pure-spin-current sources, spin-based electronic (spintronic) devices no longer require electrical charge transfer, opening new possibilities for both conducting and insulating spintronic systems. Pure spin currents have been used to suppress noise caused by thermal fluctuations in magnetic nanodevices, amplify propagating magnetization waves, and to reduce the dynamic damping in magnetic
films. However, generation of coherent auto-oscillations by pure spin currents has not been achieved so far. Here we demonstrate the generation of single-mode coherent autooscillations in a device that combines local injection of a pure spin current with enhanced spin-wave radiation losses. Counterintuitively, radiation losses enable excitation of autooscillation, suppressing the nonlinear processes that prevent auto-oscillation by redistributing the energy between different modes. Our devices exhibit auto-oscillations at moderate
current densities, at a microwave frequency tunable over a wide range. These findings suggest a new route for the implementation of nanoscale microwave sources for nextgeneration integrated electronics.