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MA: Fachverband Magnetismus
MA 26: Ultrafast Magnetization Effects I
MA 26.6: Vortrag
Mittwoch, 19. März 2025, 16:15–16:30, H16
Ultrafast magnetization dynamics of magnetic garnet thin films — •Paul Herrgen1, Christian Holzmann2, Manfred Albrecht2, Benjamin Stadtmüller2, and Martin Aeschlimann1 — 1Department of Physics and Research Center OPTIMAS, RPTU Kaiserslautern-Landau, 67663 Kaiserslautern, Germany — 2Institute of Physics, University of Augsburg, 86159 Augsburg, Germany
The rare-earth iron garnets (REIG) are a class of magnetic oxide materials, known for their excellent magneto-optical properties, high magnetic permeability, and applications in photonics and spintronics. [1]
In our work we investigate the ultrafast magnetization dynamics of a gadolinium iron garnet (GdIG) thin film after an excitation with an ultrashort laser pulse. Our static characterization of the magnetic properties revealed hysteresis loops with opposite sign of the saturation magnetization for equal field directions depending on the probe photon energy. This points to a photon energy dependent magnetic response of both sublattices and allows us to disentangle their ultrafast response after optical excitation. We observe an ultrafast demagnetization of both sublattices within the first few hundred fs, after excitation with photon energies larger than the material's band gap. We find a different quenching for the signals of both sublattices despite the otherwise very similar demagnetization time. On longer timescales, we find another different behavior for the sublattices, with the iron sublattice starting to remagnetize much earlier than the gadolinium one.
[1]: C. Holzmann and M. Albrecht: Encyclopedia of Materials: Electronics 1, 777 (2023)
Keywords: Ultrafast; Demagnetization; MOKE; Garnet