Different domain structures and their effects on fatigue behavior in Bi3TiTaO9 and SrBi2Ta2O9 ceramics

The domain structures of Bi3TiTaO9 (BTT) and SrBi2Ta2O9 (SBT) ceramics, which have the same crystalline structure but different fatigue properties, were studied by transmission electron microscopy. Antiphase boundaries and 90degrees domain walls in BTT ceramics were confirmed by the dark-field image taken with (031) superlattice reflection and selected area diffraction patterns, respectively. In contrast to SBT, 90degrees ferroelectric domains in BTT display a high, flat morphology and less density. Additionally, a type of planar defects normal to the c axis, which has not been found in SBT, was observed. The origin of different domain structures is discussed. The mechanism of fatigue behavior related to 90degrees domains is also proposed. (C) 2003 American Institute of Physics.