Ferroelectric and piezoelectric properties of Aurivillius phase intergrowth ferroelectrics and the underlying materials design

Ferroelectric and piezoelectric properties of the La-doped intergrowth Aurivillius phase ceramics Bi 5-xLa xTiNbWO 15 and Bi 7-xLa xTi 4NbO 21 (x = 0.00-1.75) were studied. It was found that the La doping is in favour of the domain switching. Owing to the impact of defects, the P-E hysteresis loops of the La-doped Bi 5TiNbWO 15 ceramics are un-symmetrical and the piezoelectric coefficients are quite low. Enhanced ferro-/piezoelectric properties, such as 2P r of 24.4 μC/cm 2 (x = 0.50) and d 33 of 16.6 pC/N (x = 0.75), were obtained in the Bi 7-xLa xTi 4NbO 21 ceramics. The high temperature electrical behaviour indicates that the Bi 5-xLa xTiNbWO 15 ceramics are semiconducting whereas the La-doped Bi 7Ti 4NbO 21 ceramics are worthy to be further studied toward high temperature piezoelectric applications. Finally, the underlying materials design is discussed. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.