铁电畴开关特性与生长控制
吕笑梅
南京大学
摘要：铁电畴的存在及形态演变是影响铁电材料性能的重要因素之一。本报告将主要介绍压电力显微镜研究铁电畴开关与控制的部分实验工作，分三部分内容。（1）LiNbO3光电晶体中电畴的生长、弛豫与形态控制；（2）基于二维压电力显微镜的多晶材料电畴开关研究方法以及多晶BiFeO3薄膜的电畴开关特性；（3）（001）外延BiFeO3薄膜中的电畴开关以及铁电涡旋畴。


Studies of the energy levels of point defects in perovskite oxides using conductivity methods

Prof. Igor Raevski,
Southern Federal University, Rostov-on-Don, Russia

In contrast to classical semiconductors, like Ge or Si, complex oxides of the ABO3 type (A and B-different metals) possessing the perovskite structure, contain a high concentration of the intrinsic point defects, mainly the vacancies in the O- , A- , or/and B-sublattices. These defects are usually called zero- dimensional defects. If the concentration of these defects increases, they can order, forming at first dislocations (one- dimensional defects) and then – crystallographic shear planes (two- dimensional defects). Doping of ABO3 perovskites by aliovalent ions usually leads mainly to the changes in the relative concentrations of intrinsic defects.
The main regularities of the energy band structure of ABO3 perovskites as well as the energies of the main types of intrinsic point defects will be discussed. Some results of the studies of the energy levels of point defects in perovskite oxides using conductivity methods (temperature dependence of dc conductivity, spectral dependence of the photoconductivity, non-equilibrium thermally stimulated conductivity) will be presented.