Comparison of Effective Direct and Converse Magnetoelectric Effects in Laminate Composites

A theoretical analysis is used to prove that a piezoelectric/magnetostrictive laminate composite has equivalent effective direct and converse magnetoelectric (ME) coefficients. Experimentally a PZT/Terfenol-D/PZT trilayer laminate composite was fabricated and both direct and converse ME coefficients were characterized by measuring the magnetic-field-induced polarization and electric-field-induced magnetization. The laminate sample exhibits similar DC magnetic bias dependence and resonance response for both direct and converse ME effects. The magnitudes of effective ME coefficients are of the same order but significantly different and both are smaller than theoretical prediction. This raises the question as to whether these coefficients are equivalent in a layered composite or to the accuracy of ME coefficient data measurement.