Synthesis, X-ray structure analysis, and Raman spectroscopy of R2TiO5-based (R = Sc, Y) solid solutions

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• 作者：L. P. Lyashenko ; L. G. Shcherbakova ; A. I. Karelin ; V. A. Smirnov…
• 刊名：Inorganic Materials
• 出版年：2016
• 出版时间：May 2016
• 年：2016
• 卷：52
• 期：5
• 页码：483-489
• 全文大小：889 KB
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Chemistry
  Inorganic Chemistry
  Industrial Chemistry and Chemical Engineering
  Materials Science
  Russian Library of Science
  
• 出版者：MAIK Nauka/Interperiodica distributed exclusively by Springer Science+Business Media LLC.
• ISSN：1608-3172
• 卷排序：52

文摘

Order–disorder transitions in xR₂O₃ · (1 − x)TiO₂ (R = Sc, 0.4 ≤ x ≤ 0.5; R = Y, 0.5 ≤ x ≤ 0.6) solid solutions with highly imperfect fluorite-derived structures have been studied using monochromatic synchrotron X-ray diffraction and Raman spectroscopy. The results demonstrate that the synthesis process leads to the formation of a fluorite-like (Fm3m) disordered phase and a nanoscale (~10–100 nm) pyrochlore-like (Fd3m) ordered phase of the same composition, coherent with the disordered phase. We have determined their lattice parameters. The Raman spectra of Sc₂TiO₅ (Y₂TiO₅) contain broad lines in low- and high-frequency regions: at 190, 350, and 775 (134, 188, 365, 404, and 727) cm−1. These lines are characteristic of a pyrochlore-like phase with a varying degree of order and a disordered fluorite-like phase, respectively. The pyrochlore-like phase Y₂Ti₂O₇ has two strong Raman peaks in the low-frequency region: at 312 and 527 cm−1. The formation of nanodomains with different degrees of order is caused by the internal stress that arises from the high density of structural defects in the unit cells of the solid solutions.Keywordssynchrotron X-ray diffractionRaman spectrafluorite- and pyrochlore-like Sc(Y)₂TiO₅-based solid solutions