Non-linear Piezoelectric and Dielectric Behaviors in Perovskite Ferroelectrics

Perovskite ferroelectrics have been used for many piezoelectric and dielectric applications. The responses of perovskite ferroelectrics to the applied electric field, such as strains and electric displacements, are not proportional to the strength of electric field but generally show a non-linear behavior. This paper reviews previous studies on non-linear piezoelectric and dielectric responses mainly done by the author’s research group. The mechanism generating non-linear responses is the domain-wall motion and the dipole fluctuation in the polar nano-regions of relaxors. Some experimental results of the electric-field induced strains of PZT ceramics and the non-linear dielectric behaviors of relaxors including dielectric used in multi-layered ceramic capacitors (MLCCs) are presented. The non-linear piezoelectric and dielectric behaviors of perovskite ferroelectrics are discussed to find the key issues for piezoelectric actuators and MLCCs used in future applications.