Coherent excitation of heterosymmetric spin waves with ultrashort wavelengths

Dieterle, G. et al. (2019) Coherent excitation of heterosymmetric spin waves with ultrashort wavelengths. Physical Review Letters, 122(11), 117202. (doi: 10.1103/PhysRevLett.122.117202) (PMID:30951356)

Abstract

In the emerging field of magnonics, spin waves are foreseen as signal carriers for future spintronic information processing and communication devices, owing to both the very low power losses and a high device miniaturization potential predicted for short-wavelength spin waves. Yet, the efficient excitation and controlled propagation of nanoscale spin waves remains a severe challenge. Here, we report the observation of high-amplitude, ultrashort dipole-exchange spin waves (down to 80 nm wavelength at 10 GHz frequency) in a ferromagnetic single layer system, coherently excited by the driven dynamics of a spin vortex core. We used time-resolved x-ray microscopy to directly image such propagating spin waves and their excitation over a wide range of frequencies. By further analysis, we found that these waves exhibit a heterosymmetric mode profile, involving regions with anti-Larmor precession sense and purely linear magnetic oscillation. In particular, this mode profile consists of dynamic vortices with laterally alternating helicity, leading to a partial magnetic flux closure over the film thickness, which is explained by a strong and unexpected mode hybridization. This spin-wave phenomenon observed is a general effect inherent to the dynamics of sufficiently thick ferromagnetic single layer films, independent of the specific excitation method employed.

• Item Type: Articles
• Additional Information: S. F. acknowledges funding from the EU Horizon 2020 project MAGicSky (Grant No. 665095). V. T. and A. N. S .acknowledge funding by the Grant No. EFMA-1641989 from the National Science Foundation of the USA, by the grant from DARPA, and by the grant from the Center fo rNanoFerroic Devices (CNFD) and Nanoelectronics Research Initiative (NRI). D. A. B. and H. Yu. M.-S. acknowledge support by the DFG within Spin +X SFB/TRR 173. S. W. acknowledges funding from the European Community’s Seventh Framework Programme (FP7/2007-2013) under Grant Agreement No. 290605 (PSI-FELLOW/COFUND).
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Bozhko, Dr Dmytro
• Authors: Dieterle, G., Förster, J., Stoll, H., Semisalova, A.S., Finizio, S., Gangwar, A., Weigand, M., Noske, M., Fähnle, M., Bykova, I., Gräfe, J., Bozhko, D.A., Musiienko-Shmarova, H.Y., Tiberkevich, V., Slavin, A.N., Back, C.H., Raabe, J., Schütz, G., and Wintz, S.
• College/School: College of Science and Engineering > School of Engineering > Electronics and Nanoscale Engineering
• Journal Name: Physical Review Letters
• Publisher: American Physical Society
• ISSN: 0031-9007
• ISSN (Online): 1079-7114