  An unexplored physical mechanism which produces a magnetoelectric effect in
ferroelectric/ferromagnetic multilayers is studied based on first-principles
calculations. Its origin is a change in bonding at the
ferroelectric/ferromagnet interface that alters the interface magnetization
when the electric polarization reverses. Using Fe/BaTiO3 multilayers as a
representative model we show a sizable difference in magnetic moments of Fe and
Ti atoms at the two interfaces dissimilar by the orientation of the local
electric dipole moment. The predicted magnetoelectric effect is comparable in
magnitude with that observed in elastically-coupled composites and opens a new
direction to control magnetic properties of thin-film layered structures by
electric fields.
