Defect chemistry of a high-k ¡®Y5V¡¯ (Ba_0.95Eu_0.05)TiO₃ ceramic

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• 作者：Da-Yong Lu^a ; ^{cninjp11232000@yahoo.com} ; ^{dylu@jlict.edu.cn} ; Li Zhang^a ; ^b ; Xiu-Yun Sun^a
• 关键词：A. Powders ; solid state reaction and Sintering ; B. Defects ; C. Dielectric properties ; D. BaTiO3 and titanates
• 刊名：Ceramics International
• 出版年：2013
• 出版时间：August, 2013
• 年：2013
• 卷：39
• 期：6
• 页码：6369-6377
• 全文大小：1488 K

文摘

The influence of the sintering temperature (T_s) on the structure, dielectric and valence-state properties of (Ba_1?xEu_x)TiO₃ (x=0.05) ceramics was investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), electron paramagnetic resonance (EPR), Raman spectroscopy, and dielectric temperature measurements. An increase in T_s can increase the solubility limit of Eu in BaTiO₃. When the T_s was increased to 1450 ¡ãC, a high-k ¡®Y5V¡¯ (¦Å¡ä_RT=8500) ceramic (C-BE5T) with a single-phase cubic structure was obtained. The dielectric peak shifted rapidly toward lower temperatures with increasing T_s at a rate of ?0.46 ¡ãC/K. A symmetric (200) XRD peak, exaggerated grain growth (5.6 ¦Ìm), a mixed valence of Eu²⁺/Eu³⁺, an asymmetric main Raman band at 2494 cm^?1 and a weak sharp band at 1516 cm^?1 in the high-wavenumber region are characteristics of cubic symmetry of C-BE5T. The formation of a solid solution of C-BE5T and defect chemistry are discussed.