Correlation Between Cation Vacancies and Phase Transition Behavior in SrBi2Ta2O9 Doped with Praseodymium

Polycrystalline samples of SrBi2Ta2O9 doped with Praseodymium and cation vacancies have been studied. DRX characterization shows that the Aurivillius structure can accept up to 15% of induced vacancies without the precipitation of second phases. Thermoelectric analysis and ferroelectric hysteresis measurements were performed and show that the introduction of vacancies in the Aurivillius structure modifies the transition temperature and the polarization properties. Broad phase transitions were also observed as a consequence of the cationic disorder which alters the nature of the phase transition. The introduction of vacancies in SBT produces a notable decrease in Tc and a remarkable increase of the permittivity around the transition temperature.