A focused-ion-beam-assisted technique intended for ultrasmall, hard-magnet fabrication has been developed. By means of ion-beam-induced milling and deposition, reduced-size NdFeB magnets were extracted from a macroscopic quarry and bonded to the surface of a thin-film bulk acoustic resonator (FBAR). Electrical characterization of the FBAR before and after bonding of the magnet was carried out, thus observing both a downshifting of the resonance frequency and a reduction of the quality factor of the resonator. The magnetic behavior of the nanomagnet has been confirmed by means of magnetometry measurements based on atomic force microscopy.