It is suggested that thin wafers of a magnetostrictive material may be used as emitters of rf ultrasound. Single crystals of manganese zinc ferrite, which have high magnetostriction constants and low Foucault current losses, were used to investigate the orientational field dependences of the efficiency of excitation of acoustic waves having different polarizations. Some distinguishing features of the excitation of sound by single-crystal wafers compared with polycrystalline samples were observed, and the direction of propagation and polarization of the sound wave and its polarization relative to the crystallographic axes of manganese zinc ferrite with the highest conversion efficiency was identified.