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MA: Fachverband Magnetismus

MA 3: Ultrafast Magnetization Effects I

MA 3.1: Hauptvortrag

Montag, 18. März 2024, 09:30–10:00, H 2013

Effects of Magnetization Inertia in Spin Dynamics — •Anna Semisalova — Faculty of Physics and CENIDE, University of Duisburg-Essen, Duisburg, Germany

Magnetization inertia has been shown to give rise to an additional motion of magnetization - a THz-frequency nutation, superimposed on the regular GHz precession [1-4], attractive for ultrafast magnonics [5]. Furthermore, in nanoparticles, magnetic nutation can be induced by a non-uniform spin configuration due to surface anisotropy [6]. In this talk, I discuss how to resolve effects of inertia on spin dynamics in anisotropic ferromagnets [7]. Within the inertial LLG equation, we find a reduction of the ferromagnetic resonance (FMR) frequency for both aligned and non-aligned modes due to inertia. We illustrate this phenomenon for model thin film systems with cubic and uniaxial magnetocrystalline anisotropy. Notably, for an out-of-plane magnetic field the FMR frequency dependence of a thin film becomes non-linear, in contrast to conventionally used Kittel formula. We also find that the nutation frequency increases with the magnetic anisotropy and the applied field. These higher-order corrections due to inertia are important for an accurate evaluation of magnetic anisotropy and g-factor, and for an interpretation of spin dynamics experiments at higher frequencies [7]. Support from DFG is gratefully acknowledged (SE 2853/1-1 | AL 618/37-1; CRC/TRR 270). [1] PRB 83, 020410(R) (2011); [2] PRB 102, 184432 (2020); [3] Nat. Phys. 17, 245 (2021); [4] JMMM 579, 170830 (2023); [5] PRB 103, 174435 (2021); [6] PRB 98, 165444 (2018); [7] PRB 106, 054428 (2022)

Keywords: spin dynamics; ferromagnetic resonance; inertia of magnetization; magnetic anisotropy