The experimental investigations on frequency dependence of ferroelectric properties in soft PZT-5 ceramics

In this work the coupled electromechanical behaviors of the overall properties of ferroelectric ceramics have been experimentally studied with different initial poling states and loading frequencies in order to have a better understanding of their domain switching mechanism. The material under investigation is soft PZT-5 ceramic, which shows noticeable nonlinear response upon externally applied load. The experimental results show that the state of initial poling in the specimens can evidently affect the characteristics of the hysteresis loops. The electrical loading frequency dependence of the ferroelectric properties of PZT-5, e.g., coercive field, remnant polarization, etc., has also been investigated through the tests conducted on the carefully designed multi-field testing system. Despite some common features of frequency dependence shared by all three types of initial poling, it is found out that the effects of loading frequency on the change of coercive field and remnant polarization for the specimen poled perpendicular to the switching axis deviate from those of the other two poling states, and this may be attributed to the specific domain switching mechanism for the perpendicularly poled specimen.