Dielectric nonlinearity of stack piezoelectric actuator under the combined uniaxial mechanical and electric loads

Abstract

The dielectric nonlinearity of stack lead zirconium titanate (PZT) piezoelectric actuator was investigated under the combined uniaxial mechanical and electric loads. In the intermediate electric field region (Rayleigh region), the Rayleigh coefficient increases at less than 50 MPa, beyond which it declines. Similarly, the dielectric nonlinearity identified by P-E hysteresis loop, revealed by both the dielectric measurement and the Rayleigh law fitting, also shows an initial increase at less than 50 MPa and a subsequent decrease when stress is above 50 MPa. In the high electric field region, the dielectric nonlinearity declined continuously with increasing stress, which leads to a fact that a boundary between the Rayleigh region and high field region becomes smeared. These results could be interpreted as the influences of the applied stress on ferroelectric domain-related contributions to dielectric response, which is very important to the practical application of stack piezoelectric actuators.