Equivalent circuit method for static and dynamic analysis of magnetoelectric laminated composites

Magnetoelectric equivalent circuit analytical method is presented for laminate composites of magneto- strictive Terfenol-D (TbxDy1-xFe2) and piezoelectric Pb(Zr1-xTix)O3 (PZT) operated in longitudinal mag- netized and transverse polarized (or L-T), and transverse magnetized and transverse polarized (or T-T) modes. Magnetoelectric (ME) couplings both at low-frequency and resonance-frequency have been studied, and our analysis predicts that (i) the ME voltage coefficients of both L-T and T-T modes in- crease with increasing the thickness of the piezoelectric phase whereas magnetostrictive phase thickness keeps constant, and then tend to saturation when the thickness ratio of piezoelectric phase to magnetic phases is >3; (ii) there are the optimum thickness ratios that maximize magnetoelectric (ME) voltage coefficients for the two modes, which are dependent on elastic compliances ratio of piezoelec- tric phase and magnetostrictive phase; and (iii) the ME voltage coefficients are dramatically increased by a factor of ~Qm, when operated at resonance frequency. A series of Terfenol-D/PZT laminates were fabricated, and the results were compared with the theoretical ones. Experiments confirmed that equivalent circuit method is a useful tool for optimum designs of ME laminates.