An aspect of a magnetic vortex whose dynamics strongly affects the magnetic structures of the environment is experimentally shown. We exploit a nanodot of an exchange-coupled bilayer with a soft magnetic Ni81Fe19 [permalloy (Py)] having a magnetic vortex and a perpendicularly magnetized L10-FePt exhibiting a large switching field (Hsw). The vortex dynamics with azimuthal spin waves makes the excess energy accumulate in the Py, which triggers reversed-domain nucleation in L10-FePt at a low magnetic field. Our experimental and numerical results shed light on the essence of reversed-domain nucleation, and provide a route for efficient Hsw reduction.
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