Linearly polarized GHz magnetization dynamics of spin helix modes in the ferrimagnetic insulator Cu$_{2}$OSeO$_{3}$
Autor: | Stasinopoulos, I., Weichselbaumer, S., Bauer, A., Waizner, J., Berger, H., Garst, M., Pfleiderer, C., Grundler, D. |
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Rok vydání: | 2017 |
Předmět: | |
Druh dokumentu: | Working Paper |
DOI: | 10.1038/s41598-017-07020-2 |
Popis: | Linear dichroism -- the polarization dependent absorption of electromagnetic waves -- is routinely exploited in applications as diverse as structure determination of DNA or polarization filters in optical technologies. Here filamentary absorbers with a large length-to-width ratio are a prerequisite. For magnetization dynamics in the few GHz frequency regime strictly linear dichroism was not observed for more than eight decades. Here, we show that the bulk chiral magnet Cu$_{2}$OSeO$_{3}$ exhibits linearly polarized magnetization dynamics at an unexpectedly small frequency of about 2 GHz. Unlike optical filters that are assembled from filamentary absorbers, the magnet provides linear polarization as a bulk material for an extremely wide range of length-to-width ratios. In addition, the polarization plane of a given mode can be switched by 90$^\circ$ via a tiny variation in width. Our findings shed a new light on magnetization dynamics in that ferrimagnetic ordering combined with anisotropic exchange interaction offers strictly linear polarization and cross-polarized modes for a broad spectrum of sample shapes. The discovery allows for novel design rules and optimization of microwave-to-magnon transduction in emerging microwave technologies. Comment: 20 pages, 4 figures |
Databáze: | arXiv |
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