We investigate magnetization dynamics of Mn2Au/Py (Ni80Fe20)
thin film bilayers using broadband ferromagnetic resonance (FMR) and Brillouin
light scattering spectroscopy. Our bilayers exhibit two resonant modes with
zero-field frequencies up to almost 40 GHz, far above the single-layer Py FMR.
Our model calculations attribute these modes to the coupling of the Py FMR and
the two antiferromagnetic resonance (AFMR) modes of Mn2Au. The
coupling-strength is in the order of 1.6 T⋅nm at room temperature for
nm-thick Py. Our model reveals the dependence of the hybrid modes on the AFMR
frequencies and interfacial coupling as well as the evanescent character of the
spin waves that extend across the Mn2Au/Py interfac