Ferroelectric and conductivity behavior of multilayered PbZr_(0.52)Ti_(0.48)O_3/Pb(Mg_(1/3)Ta_(2/3))_(0.7)Ti_(0.3)O_3/PbZr_(0.52)Ti_(0.48)O_3thin films

摘要

Ferroelectric and impedance behavior of sandwich-structured PbZr_(0.52)Ti_(0.48)O_3/Pb (Mg_(1/3)Ta_(2/3))_(0.7)Ti_(0.3)O_3/PbZr_(0.52)Ti_(0.48)O_3 thin films was studied as a function of temperature (23-300 ℃) and frequency (0.1 -10~4 Hz). A change in the controlling mechanism of the electrical behavior from grain interior to grain boundary occurred in the temperature range studied. A low-frequency dielectric relaxation was observed in the temperature range of 200-300 ℃, the activation energy of which was calculated to be 0.90 eV. This suggests that oxygen vacancies are the most likely charge carriers at high temperatures. The change in fatigue behavior of the sandwich-structured thin film with temperature can be accounted for by the increased mobility of oxygen vacancies at elevated temperatures. Frequency dependent conductivities were analyzed with an augmented Jonscher relation. The activation energies for dc conductivity and hopping frequency were calculated to be 0.90 and 0.89 eV, respectively.