Synthesis by two methods and crystal structure determination of a new pyrochlore-related compound Sm₂FeTaO₇

详细信息	查看全文 | 推荐本文 |

• 作者：Leticia M. Torres-Martí ; nez^a ; ^{lettorresg@yahoo.com} ; Miguel A. Ruiz-Gó ; mez^a ; ^b ; M.Z. Figueroa-Torres^a ; Isaí ; as Juá ; rez-Ramí ; rez^a ; Edgar Moctezuma^b ; Enrique Ló ; pez Cué ; llar^c
• 关键词：Chemical synthesis ; Powder diffraction ; Rietveld analysis ; Crystal structure
• 刊名：Materials Chemistry and Physics
• 出版年：2012
• 期刊代码：58_02540584
• 类别：ms
• 出版时间：16 April, 2012
• 卷：133
• 期：2-3
• 页码：839-844
• 文件大小：840 K

摘要

This paper reports on the synthesis of a new pyrochlore-related compound Sm₂FeTaO₇ by both solid state reaction and sol-gel synthesis routes. Structural features were determined by X-ray powder diffraction and Rietveld refinement and were corroborated using Transmission Electron Microscopy (TEM). The results revealed that Sm₂FeTaO₇ crystallized in the monoclinic system with space group C2/c and the following cell parameters: a = 13.1307(5) 脜, b = 7.5854(3) 脜, c = 11.6425(4) 脜 and 尾 = 100.971(2)掳. The monoclinic structure of Sm₂FeTaO₇ showed an arrangement of alternating SmO and Fe/TaO layers and two types of irregular octahedra of Fe/TaO, which are interconnected into a hexagonal tungsten bronze (HTB)-type network. On the other hand, Sm₂FeTaO₇ prepared by sol-gel was obtained with lower particle sizes than the solid state produced compound. The difference in particle size causes a difference of one order of magnitude in the specific surface area. In addition, energy band gap (E_g) of Sm₂FeTaO₇ has a low value of around 2.0 eV.