Abstract
The dependence of the dielectric constant on the electric field of PZT ceramics can be well explained by the mechanism of domain wall motion. The mobility of the domain wall is increased by the A-site vacancies, due to the reduction of local stress in the domains which undergo domain switching. But O-site vacancies and the grain boundary act as pinning points for domain walls, so the domain wall motion is reduced when O-site vacancies dominate and the grain size is small. As a result, the dielectric constant after poling was larger than that before poling and the coercive field were reduced by the addition of A-site vacancy produce. But the opposite results were obtained, when the O-site vacancy produce was added.