MAGNETOELECTRIC EFFECT IN PIEZOELECTRIC MAGNETOSTRICTIVE MULTILAYER (2-2) COMPOSITES

We consider the magnetoelectric effect arising in a multilayer composite consisting of bonded layers of a piezoelectric ceramic and a magnetostrictive material operating in the linear regime. Magnetoelectric coupling arises from the mechanical contacts between layers and the electric/mechanical and magnetic/mechanical coupling in each phase. Calculations of the magnetoelectric coefficient alpha* as well as of the figures of merit k(me) and k(me, cl) are presented. These calculations fully take into account the electric, magnetic and mechanical mismatch in the material properties, as well as the volume-fractions of both materials. We derive the optimal volume fraction f1crit of piezoelectric material needed to maximize the figure of merit k(fme) or k(me, cl) for the composite and give criteria for optimizing the magnetoelectric effect in terms of the choice of the individual constituents. We computed the figures of merit of a variety of piezoelectric/magnetostrictive combinations. The combinations CoFe2O4/PZT5H (k(me) = 14%), Terfenol D/PZT5A (k(me) = 22%) and Terfenol D/PZT4 (k(me) = 30%) show reasonable energy transfer to be useful as magnetoelectric transducers.