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MA: Fachverband Magnetismus

MA 26: Ultrafast Magnetization Effects I

MA 26.2: Vortrag

Mittwoch, 19. März 2025, 15:15–15:30, H16

Photoinduced spectral manipulation of coherent magnonics in ultrathin iron garnets — •Volker Wiechert¹, Moritz Cimander¹, Hanchen Wang², William Legrand³, Pietro Gambardella², and Davide Bossini¹ — ¹Department of Physics, University of Konstanz, D-78457 Konstanz, Germany — ²Department of Materials, ETH Zürich, Hönggerbergring 64, CH-8093 Zürich, Switzerland — ³Unité Mixte de Physique, CNRS, Université Paris-Saclay, Palaiseau 91767, France

Iron garnets, particularly Bi:YIG thin films, are promising materials for magnonics and magnetotransport due to their low damping and tunable magnetic properties through doping or external magnetic fields [1]. Recent advances demonstrate the ability of ultrashort laser pulses to excite, control, and even switch magnetization with minimal heating [2-4]. In this study, we investigate Bi:YIG single crystals in quasi-2D ultrathin form (~20 nm), using a femtosecond, balanced-detection scheme to capture simultaneous optical and magneto-optical responses. Our findings reveal two pathways for modifying magnetic resonance eigenfrequency: an impulsive femtosecond modification of magneto-crystalline anisotropy and a nanosecond lattice-mediated heating effect. This dual effect is quantitatively identified in time-resolved experiments, with potential applications in other quasi-2D ultrathin magnetic systems exhibiting temperature-dependent phase transitions.

[1] C. Holzmann et al., ACS Appl. Nano Mater. 5(1), 2022 [2] F. Hansteen et al., PRB 73, 2006 [3] L. Soumah et al., PRL 127, 2021 [4] A. Stupakiewicz et al., Nature 542, 2007

Keywords: Ultrafast Magnetization Dynamics; Bi:YIG; Pump-Probe Experiments