Bismuth titanate-based high temperature piezoceramics: Domain structure and polarization dynamics

用PFM和TEM技术研究了BIT钙钛矿型压电体中的磁畴结构。透射电子显微镜实验结果表明，纯BIT陶瓷中主要存在(110)型90度磁畴壁。然而，对于掺杂的BIT陶瓷，在晶粒的侧面上出现了大量的(001)型180度磁畴壁。通过三维PFM实验，结合STEM对离子位移和极化位移的原子观测，成功地建立了空间可视化模型。此外，利用导电PFM探头初步研究了BIT陶瓷的极化开关，揭示了极化矢量沿晶胞a轴和c轴的独立开关行为。

Domain structures in BIT perovskite piezoelectrics were probed by PFM and TEM techniques. The TEM experimental results show that there mainly exist (110)-type 90 degree domain walls in the pure BIT ceramics. However, for the doped BIT ceramics, numerous (001)-type 180 degree domain walls appear on the lateral planes of grains. These domain walls were further examined by 3D PFM experiments, whose spatially visualized models were successfully established combined with the atomic observations of ion displacement and polarization shift via STEM. In addition, the polarization switching of BIT ceramics was initially investigated by a conductive PFM probe, which reveals the independent switching behaviors of polarization vector along a-axis and c-axis of unit cell.