Temperature and frequency dependent defect dipole kinematics in “hard” piezoelectric ceramics

“Hard” piezoelectric ceramics exhibit typical shifted hysteresis loops due to the presence of oxygen vacancies and defect dipoles. The kinetic characteristics of oxygen vacancies and defect dipoles significantly affect the hardening effect and application scenario of “hard” piezoelectric ceramics. The scaling behavior of the internal bias field is an effective method to investigate the kinetic characteristics of oxygen vacancies and defect dipoles. This work systematically studied the temperature and frequency-dependent relation of the internal bias field in “hard” lead zirconate titanate (PZT-8) ceramics with tetragonal phase. The linear relation of the internal bias field on the temperature and electric field amplitude is given. Simultaneously, the internal bias field exhibits distinct relaxation characteristics with the frequency variation. The stretching relaxation relation between internal bias field and frequency was also determined. In addition, the kinetic characteristics of oxygen vacancy and defect dipole dependent on frequency and temperature were studied and analyzed. Our works provide the scientific theory of defect kinetics for hard-doping perovskite ferroelectrics and guide the device application of “hard” PZT ceramics.