Order and Disorder in Rocksalt and Spinel Structures in the MgS-Yb2S3 System

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• 作者：Esteban Urones-Garrote ; Adriá ; n Gó ; mez-Herrero ; Á ; ngel R. Landa-Cá ; novas ; Ray L. Withers ; and L. Carlos Otero-Dí ; az
• 刊名：Chemistry of Materials
• 出版年：2005
• 出版时间：June 28, 2005
• 年：2005
• 卷：17
• 期：13
• 页码：3524 - 3531
• 全文大小：1318K
• 年卷期：v.17,no.13(June 28, 2005)
• ISSN：1520-5002

文摘

The MgS-Yb₂S₃ solid solution, which can be formulated as Mg_1-xYb_(2/3)x(1/3)xS (, cation vacancy),was studied in a wide composition range (0 x 0.75). The structure and microstructure characterizationsof the samples were mainly performed via transmission electron microscopy (TEM) and associatedtechniques, such as X-ray energy dispersive spectroscopy (XEDS) and electron energy-loss spectroscopy(EELS). At low Yb³⁺ contents (x 0.30), the system presents an average NaCl-type structure. Theselected area electron diffraction (SAED) patterns corresponding to these crystals show diffuse scatteredintensity, which is related to short-range order in the cation sublattice. EELS studies indicate the existenceof Mg²⁺ in tetrahedral coordination, in addition to the octahedral coordination of the basic NaCl-typestructure. Extended defects were observed perpendicular to <111> in the NaCl matrix for the x = 0.30sample. When x 0.35, a phase with spinel-type structure is observed and characterized. Besides, differentdefects with different structure were also observed perpendicular to <111> in the spinel matrix for 0.35 x 0.45 samples.