  Ferromagnetic resonance modes in a single rectangular Ni$_{80}$Fe$_{20}$
microstrip were directly imaged using time-resolved scanning transmission x-ray
microscopy combined with a phase-locked ferromagnetic resonance excitation
scheme and the findings were corroborated by micromagnetic simulations.
Although under uniform excitation in a single confined microstructure typically
standing spin waves are expected, all imaged spin waves showed a nonstanding
character both, at and off resonance, the latter being additionally detected
with microantenna-based ferromagnetic resonance. The effect of the edge quality
on the spin waves was observed in micromagnetic simulations.
