SKM 2023 – scientific programme
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MA: Fachverband Magnetismus
MA 40: Poster Magnetism II
MA 40.7: Poster
Thursday, March 30, 2023, 14:00–16:00, P2/EG
Coherent excitation of spin waves in thin nickel films during ultrafast remagnetization — •Akira Lentfert1, Anulekha De1, Laura Scheuer1, Benjamin Stadtmüller1,2, Burkard Hillebrands1, Georg von Freymann1,3, Martin Aeschlimann1, and Philipp Pirro1 — 1Department of Physics and Research Center OPTIMAS, RPTU Kaiserslautern-Landau, Germany — 2Institute of Physics, Johannes Gutenberg University Mainz, Germany — 3Fraunhofer Institute for Industrial Mathematics ITWM, Germany
The remagnetization process after ultrafast demagnetization can be described by relaxation mechanisms between the spin, electron, and lattice reservoirs. The angular momentum transfer between them is the subject of current research, especially the role of collective spin excitations remains comparably unexplored. In our work, we study the pump fluence-dependent excitation of coherent spin waves in thin nickel films. Using the all-optical, time-resolved magneto-optical Kerr-effect (tr-MOKE) technique, we investigate the role of coherent spin waves after the laser-induced demagnetization. We show that the largest spin-wave amplitude is observed close to the fully demagnetized state. Furthermore, the coherence of the system appears to be conserved during de- and remagnetization, even when the magnetization is quenched by up to 90%. Interestingly, the phase of the coherent oscillations relative to the initial laser pulse is strongly dependent on the laser fluence which indicates that the coherent precession is influenced by the demagnetization itself. This research was supported by the DFG through No. TRR 173-268565370 (project B11).