The effect of uniaxial pressure, temperature and electric field on the internal bias field in the lead-based piezoelectric ceramics

The internal bias field effects in ferroelectrics had been widely investigated in past decade, but the reasons for the formation of internal bias field are still a lot of disputes. Our works were focused on the external environment-dependent behaviors of the internal bias field, which is critical important to explain the cause for the internal bias field formation. Experiments result that a large internal bias field 4.2 kV/cm was obtained in the poled Mn-doped PNZST ceramics. A microscopic model for the domain-related ferroelectric effect in ceramics is proposed. It is also found that the internal bias field is stable under load the 90 Mpa uniaxial pressure and shows a good stability even after 107 fatigue cycles. This effect is related to the defect dipoles are rather stable due to the immobility of oxygen vacancies. Furthermore, it is suggested that the internal bias field can be decreased by increasing the temperature. These results provided direct critical experiment to understand the movement mechanisms of defect dipoles.