Regensburg 2022 – scientific programme

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MA: Fachverband Magnetismus

MA 7: Magnetic Relaxation and Gilbert Damping

MA 7.2: Talk

Monday, September 5, 2022, 11:15–11:30, H43

Magnetization dynamics affected by phonon pumping — •Richard Schlitz¹, Luise Siegl², Takuma Sato³, Weichao Yu⁴, Gerrit E. W. Bauer³, Hans Huebl⁵, and Sebastian T. B. Goennenwein² — ¹Department of Materials, ETH Zürich, 8093 Zürich, Switzerland — ²Department of Physics, University of Konstanz, 78457 Konstanz, Germany — ³Tohoku University, Sendai 980-8577, Japan — ⁴State Key Laboratory of Surface Physics and Institute for Nanoelectronic Devices and Quantum Computing, Fudan University, Shanghai 200433, China — ⁵Walther-Meißner-Institute, Bayerische Akademie der Wissenschaften, 85748 Garching, Germany

Coupling magnetic and acoustic excitations enables novel functionalities for magnonic devices. We explore broadband ferromagnetic resonance (FMR) in a Y₃Fe₅O₁₂ film on a Gd₃Ga₅O₁₂ substrate. At low frequencies, the Kittel mode hybridizes with standing ultrasound waves that form across the layer stack resulting in a characteristic modification of the magnetic susceptibility. At higher frequencies, the individual phonon resonance overlap, leading to a permanent emission of phonons and thus an enhanced relaxation of the FMR. The broadband frequency dependence of the magnetoelastic coupling and thus the phonon pumping follows theoretical predictions. We additionally find substantial magnon-phonon coupling of a perpendicular standing spin wave mode. This evidences the importance of the mode overlap between the acoustic and magnetic modes and thus paves the way to tailoring the magnetoelastic mode coupling.

[1] R. Schlitz et al., arxiv:2202.03331 (2022)