Regensburg 2022 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
MA: Fachverband Magnetismus
MA 28: Magnonics 2
MA 28.2: Vortrag
Donnerstag, 8. September 2022, 09:45–10:00, H43
Frequency multiplication by collective nanoscale spin wave dynamics — •Chris Körner1, Rouven Dreyer1, Martin Wagener2, Niklas Liebing1, Hans G. Bauer3, and Georg Woltersdorf1 — 1Department of Physics, Martin Luther University HalleWittenberg, Von-Danckelmann-Platz 3, 06120 Halle, Germany — 2Institute for Quantum Electronics, ETH Zürich, Otto-Stern-Weg 1, 8093 Zürich, Switzerland — 3Jahnstrasse 23, 96050 Bamberg, Germany
We observe all-magnetic frequency multiplication and the generation of a 6-octave spanning frequency comb within an extended polycrystalline NiFe layer [1]. We investigate this process by means of super Nyquist sampling MOKE microscopy [2] and diamond NV center spectroscopy. Our experimental observations in conjunction with micromagnetic simulations reveal the mechanism of this unexpected phenomenon.
At low bias fields the magnetization locally tilts due to a magnetic ripple effect in the NiFe film. Driving the magnetization with frequencies far below ferromagnetic resonance, i.e. in the MHz range, causes rapid synchronous switching. These switching processes lead to high harmonic spin wave emission. The spin waves emitted by multiple switching events across the film interfere and form a phase stable coherent spin wave frequency comb extending into the GHz regime.
[1] Koerner et al. Science, 375 (6585), 1165-1169 (2022) [2] Dreyer et al. Phys. Rev. Materials 5, 064411 (2021)