The dispersion of spin waves in vertical meander-shaped CoFeB thin films consisting of segments located at 90{\deg} angles with respect to each other is investigated by Brillouin light scattering spectroscopy. We reveal the periodic character of several dispersive branches as well as alternating frequency ranges where spin waves are allowed or forbidden to propagate. Noteworthy is the presence of the frequency band gaps between each couple of successive modes only for wave numbers k=nπ/a, where n is an even integer number and a is the size of the meander unit cell, whereas the spectra show propagating modes in the orthogonal film segments for the other wavenumbers. The micromagnetic simulations and analytical calculations allow us to understand and explain the results in terms of the mode spatial localization and symmetry. The obtained results demonstrate the wave propagation in three dimensions opening the path for multi-level magnonic architectures for signal processing.
@article{arxiv.2007.13707,
title = {Magnonic band structure in vertical meander-shaped CoFeB thin films},
author = {Gianluca Gubbiotti and Alexandr Sadovnikov and Evgeny Beginin and Sergey Nikitov and Danny Wan and Anshul Gupta and Shreya Kundu and Giacomo Talmelli and Robert Carpenter and Inge Asselberghs and Iuliana P. Radu and Christoph Adelmann and Florin Ciubotaru},
journal= {arXiv preprint arXiv:2007.13707},
year = {2021}
}
Comments
19 pages, 6 figures. This work has received funding from the European Union's Horizon 2020 research and innovation program under grant agreement No 801055 "Spin Wave Computing for Ultimately-Scaled Hybrid Low-Power Electronics" - "CHIRON"