Magnetoelectric Effect in Piezoelectric/Magnetostrictive Multilayer (2-2) Composites

Abstract

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 elec tric/mechanical and magnetic/mechanical coupling in each phase. Calculations of the magnetoelec tric coefficient α* 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 f^crit₁ 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 constit uents. 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.