Dresden 2017 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 32: Focus Session: Magnetic Correlations in Mesoscopic Spin Structures

MA 32.1: Hauptvortrag

Mittwoch, 22. März 2017, 09:30–10:00, HSZ 01

Collective modes in magnonic vortex crystals — •Guido Meier — Max-Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149 22761 Hamburg, Germany

Collective modes in stacked disks containing magnetic vortices are investigated by ferromagnetic resonance spectroscopy and scanning transmission X-ray microscopy. In laterally coupled arrangements it has been shown recently that memory-like writing processes are possible based on the excitation of the gyrotropic mode [1]. We make use of the vertical dimension in tailored vortex stacks that drastically increases possible storage densities. The dynamics of all binary states emergent in a stack of vortices are directly observed [2]. The size of the arrangements is increased step by step to identify the different contributions to the interaction between the vortices. These contributions are the key requirement to understand complex dynamics of three dimensional vortex crystals. Both vertical and horizontal coupling determine the collective modes. In-plane dipoles strongly influence the interaction between the disks in the stacks and lead to polarity-dependent resonance frequencies [3]. Weaker contributions discern arrangements with different polarities and circularities that result from the lateral coupling of the stacks and the interaction of the core regions inside a stack. [1] M. Hänze, C. F. Adolff, M. Weigand, and G. Meier, Phys. Rev. B 91, 104428 (2015) [2] M. Hänze, C. F. Adolff, S. Velten, M. Weigand, and G. Meier, Phys. Rev. B 93, 054411 (2016) [3] M. Hänze, C.F. Adolff, B. Schulte, J. Möller, M. Weigand, and G. Meier, Sci. Rep. 6, 22402 (2016)