Effect of point defects on thermal depoling behavior of bismuth layer-structured ferroelectric ceramics

Effect of point defects on the thermal depoling behavior of bismuth layer-structured ferroelectric Bi(2)WO(6) (BW) and Sr(2)Bi(4)Ti(5)O(18) (SBT) ceramics was investigated. Point defects in BW ceramics formed defect dipoles that interacted with the ferroelectric domain structure. These defect dipoles produced pinched polarization-electric field (P-E) hysteresis loops and an irreversible reduction in d(33) after annealing below 200 degrees C. They became decoupled and randomized above 200 degrees C, and the d(33) of BW became stable with increasing temperature from 200 degrees C up to its Curie point. SBT ceramics with low defect concentration showed symmetric P-E hysteresis loops and good piezoelectric stability with increasing temperature. (c) 2010 American Institute of Physics. [doi:10.1063/1.3499627]