  We derive an analytical model for the power transfer in a magnetoelectric
film bulk acoustic resonator consisting of a piezoelectric--magnetostrictive
bilayer. The model describes the dynamic magnetostrictive influence on the
elastodynamics via an effective frequency-dependent stiffness constant. This
allows for the calculation of both the magnetic and elastic power absorption in
the resonator as well as of its energy efficiency when such a resonator is
considered as a magnetic transducer. The model is then applied to example
systems consisting of piezoelectric ScAlN and magnetostrictive CoFeB, Ni, or
Terfenol-D layers.
