Berlin 2018 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 46: Magnonics II

MA 46.7: Vortrag

Donnerstag, 15. März 2018, 16:45–17:00, H 0110

A spin waves optical pumping in reconfigurable magnonic crystal — Chia-Lin Chang¹, Szymon Mieszczak², Ronnie Tamming¹, Mateusz Zelent¹, Julius Janusonis¹, Piotr Graczyk², •Jarosław W. Kłos^2,3, and Raanan I Tobey¹ — ¹Zernike Institute for Advanced Materials, University of Groningen, Groningen, The Netherlands — ²Faculty of Physics, Adam Mickiewicz University in Poznan, Poznań, Poland — ³Ernst Moritz Arndt University, Greifswald, Germany

The laser interference pattern is used here to generate a transient magnonic crystal in Ni layer by the reduction of magnetization in periodically heated regions. The heat transferred by laser pulse produces also dynamic strain in the form of phase-locked elastic wave capable of preferentially driving precessional magnetization motion in different regions of the Ni layer. The magnetization dynamics is probed with the aid of time resolved Faraday effect. The observed spin wave dynamics is anisotropic with respect to the angle of in-plane applied magnetic field. We found that the anomalies in the angular dependence of the resonance field reveal spin wave localization effects. Calculations of the spin wave normal modes in a laterally varying magnetization landscape elucidate the localization tendencies, while an estimation of the elastic to spin wave mode excitation cross section qualitatively explains the experimental findings. Financial support from NCN Poland grants No. UMO-2012/07/E/ST3/00538 and No. UMO-2016/21/B/ST3/00452 and the EU's Horizon 2020 grant No. 644348 (MagIC).