Numerical model for the characterization of Maxwell-Wagner relaxation in piezoelectric and flexoelectric composite material

The Maxwell-Wagner polarization effect is studied for the bi-layer piezoelectric or flexoelectric material. The free charge, which characterizes the interfacial polarization, is introduced by using the complex form of dielectric permittivity via the conductivity. Under appropriate boundary conditions, the effective material coefficients, i.e. piezoelectric or flexoelectric coefficients and dielectric permittivity, can be extracted by solving a boundary value problem, and are shown to be frequency-dependent.276