  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
miniaturisation 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 hybridisation. 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.
