Frequency-dependent magnetoelectric coefficient in a magnetostrictive-piezoelectric composite as a complex quantity

The frequency dependence of the magnetoelectric effect in a magnetostrictive-piezoelectric layered composite was predicted and discussed theoretically by taking the elastic, magnetic, piezomagnetic, dielectric and piezoelectric losses of the constituent magnetostrictive and piezoelectric phases into account. The magnetoelectric coefficient was proven to be a complex quantity, and the complexity was caused by the above losses. The imaginary part of the magnetoelectric coefficient was small at low frequencies far from the resonant frequency. However, it became very large and strong frequency dispersion was observed around the resonant frequency. Moreover, the relationship between the real and imaginary parts of the magnetoelectric coefficient could be described by a Cole-Cole plot around the resonant frequency. The predicted frequency-dependent characteristics of the complex mangetoelectric coefficient were consistent with the recent experimental results.