Regensburg 2007 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 7: Micromagnetism/Computational Magnetics
MA 7.5: Vortrag
Montag, 26. März 2007, 18:00–18:15, H10
Magnetization Dynamics during Vortex-Antivortex Annihilation — •R. Hertel and Claus M. Schneider — Institut für Festkörperforschung IFF-9 "Elektronische Eigenschaften", Forschungszentrum Jülich GmbH, D-52425 Jülich, Germany
Magnetic vortices and antivortices in thin-film elements can annihilate, resulting in a homogeneous magnetization. Both, the vortex and the antivortex contain a small core magnetized perpendicular to the film plane [1]. The direction of the magnetization of the core is called the polarization. A detailed description of the magnetization dynamics of vortex-antivortex annihilation processes is obtained by micromagnetic finite-element simulations based on the Landau-Lifshitz-Gilbert equation. As an example to study such an annihilation process, we simulated the dynamic domain structure conversion in a 100 × 100 × 10 nm3 Permalloy element from a cross-tie structure to a single vortex structure. The simulations show that, depending on the relative polarization of the vortex-antivortex pair, the annihilation process is either a continuous transformation of the magnetic structure or it involves the propagation of a micromagnetic singularity (Bloch point) causing a burstlike emission of spin waves (exchange explosion) [2].
[1] Shinjo et al. Science 289, 930 (2000).
[2] R. Hertel and C.M. Schneider, PRL 97, 177202(2006).