Materials Science and Engineering, Alfred University, NY, USA.
IEEE Trans Ultrason Ferroelectr Freq Control. 2013 Feb;60(2):265-72. doi: 10.1109/TUFFC.2013.2562.
A framework for describing anion displacements from perfect octahedra in perovskites has been developed for use with neutron diffraction data sets. We describe the distortions as noncoplanar arrangements, or buckling, of oxygen ions in any central plane of the octahedron, ignoring the central cation. Nonplanar distortions of octahedra have been calculated for perovskite structures contained within the Inorganic Crystal Structure Database. We find that antiferroelectric materials have buckling angles larger than ~2° and ferroelectric materials have buckling angles between 0° and 1°. The trend is found as a function of solid solution composition and temperature for common antiferroelectrics. For example, the described method resolves a structural difference between the end members PbTiO(3) and PbZrO(3), which exhibit ferroelectric and antiferroelectric responses, respectively. This technique is applicable to other structures containing anion octahedra, e.g., pyrochlores, spinels, and tungsten bronzes.
已经开发出一种用于描述钙钛矿中完美八面体中阴离子位移的框架，用于与中子衍射数据集一起使用。我们将这些畸变描述为八面体任何中心平面中氧离子的非共面排列或翘曲，忽略中心阳离子。我们已经计算了包含在无机晶体结构数据库中的钙钛矿结构中八面体的非平面畸变。我们发现反铁电材料的翘曲角大于~2°，而铁电材料的翘曲角在 0°和 1°之间。该趋势是作为常见反铁电材料的固溶组成和温度的函数找到的。例如，所描述的方法解决了端元 PbTiO(3)和 PbZrO(3)之间的结构差异，它们分别表现出铁电和反铁电响应。该技术适用于包含阴离子八面体的其他结构，例如 pyrochlore、spinel 和 tungsten bronze。
