کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1333848 979112 2007 10 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Phase transitions in A-site substituted perovskite compounds: The (Ca1–2xNaxLax)TiO3 (0⩽x⩽0.5) solid solution
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی معدنی
پیش نمایش صفحه اول مقاله
Phase transitions in A-site substituted perovskite compounds: The (Ca1–2xNaxLax)TiO3 (0⩽x⩽0.5) solid solution
چکیده انگلیسی

The (Ca1–2xNaxLax)TiO3 (0⩽x⩽0.50⩽x⩽0.5) A-site substituted perovskite compounds have been synthesized and characterized by XRD and Raman spectroscopy at room temperature. The XRD powder diffraction study suggests that the end-member Na1/2La1/2TiO3 crystallizes in the tetragonal space group I4/mcm. The phase transition from Pbnm to I4/mcm   is located between x=0.34x=0.34 and 0.390.39 and is driven by the variation of ionic radii at the A-site. The observed Raman modes are in agreement with group theory analysis, and the relationships between the behavior of structural parameters (e.g. Ti–O–Ti bond angle), indicated by long-range order, and the corresponding Raman frequency shifts and intensity evolution, indicated by short-range order, are established and discussed in terms of the radius effect and the mass effect.

X-ray diffraction data and calculated pattern for Na1/2La1/2TiO3, the end-member of the Ca1–2xNaxLaxTiO3 (x=0.5x=0.5). The experimental data are shown as crosses, the calculated fits and difference curves as solid lines. Tick marks (upper row for internal standard silicon) indicate the calculated positions of peaks.Figure optionsDownload as PowerPoint slide

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Solid State Chemistry - Volume 180, Issue 3, March 2007, Pages 824–833
نویسندگان
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