X-ray diffraction from nonperiodic layered structures with correlations: analytical calculation and experiment on mixed Aurivillius films.
X-ray diffraction from nonperiodic layered structures with correlations: analytical calculation and experiment on mixed Aurivillius films.
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具有相关性的非周期层状结构的 X 射线衍射：混合 Aurivilius 薄膜的分析计算和实验
DOI：
10.1107/s0108767311044874
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发表时间：
2012
期刊：
影响因子：
--
通讯作者：
M. Schmidbauer
中科院分区：
文献类型：
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作者：
V. S. Kopp;V. M. Kaganer;J. Schwarzkopf;F. Waidick;T. Remmele;A. Kwasniewski;M. Schmidbauer
分析了由不同厚度、结构和化学成分的层组成的膜的X射线衍射。该无序由层的不同序列的概率来描述。当层形成平稳马尔可夫链时，得到衍射X射线强度的封闭解析表达式。所提出的模型被施加到具有这样的一维无序的Aurivillius结构的外延钛酸铋钠薄膜的衍射数据。在这种情况下，无序是由三个和四个由氧化铋夹层隔开的钙钛矿单元的随机堆叠引起的。分析计算的结果与实验数据吻合得很好，并表明，在Bi4Ti3O12相的钠的掺入导致第四钙钛矿单元的形成。
X-ray diffraction from films consisting of layers with different thicknesses, structures and chemical contents is analysed. The disorder is described by probabilities for different sequences of layers. Closed analytical expressions for the diffracted X-ray intensity are obtained when the layers form a stationary Markov chain. The proposed model is applied to the diffraction data from epitaxial sodium bismuth titanate thin films with Aurivillius structure possessing such one-dimensional disorder. In this case, the disorder is caused by a random stacking of three and four perovskite units separated by bismuth oxide interlayers. The results of analytical calculations are in good agreement with the experimental data and indicate that the incorporation of sodium in the Bi4Ti3O12 phase causes the formation of a fourth perovskite unit.