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Crystal Structure and Effective Dielectric Response of Ba 0.5 Sr 0.5 TiO 3 –MgO Composites Synthesized In Situ Process
Author(s) -
Zhang Jingji,
Ji Ludong,
Jia Xuanrui,
Wang Jiangying,
Zhai Jiwei,
Zhou Yun
Publication year - 2015
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.13242
Subject(s) - materials science , rietveld refinement , composite number , dielectric , percolation threshold , crystal structure , composite material , permittivity , x ray crystallography , diffraction , crystal (programming language) , volume fraction , mineralogy , analytical chemistry (journal) , crystallography , electrical resistivity and conductivity , chemistry , optics , physics , optoelectronics , engineering , electrical engineering , programming language , chromatography , computer science
(1 − x ) Ba 0.5 Sr 0.5 TiO 3 ( BST )– x MgO composite ceramics have been prepared in situ by a citrate–nitrate combustion process, and their crystal structure and effective dielectric response have been investigated systematically. Results reveal that MgO particles homogeneously disperse in BST particles. Rietveld refinement of X ‐ray diffraction data shows that the amount of the incorporation of MgO into BST lattice is increased with increasing the MgO volume fraction ( ƒ M ). It is identified that the incorporation of Mg 2+ into B site gives rise to the formation of F centers in the composites. Related with the incorporation of Mg 2+ into BST lattice, the permittivity of BST in the composite is strongly dependent on ƒ M , which is defined by the relationε BST = a × e b × f M. Also, the high percolation threshold of ƒ M = 0.60 is observed, which is well in agreement with the theoretical predictions of the modified effective medium approximation coupled with the spherical inclusion model.