Superlattice ordered structures of (A<sub>x</sub>A<sub>1-x</sub>)BO<sub>3</sub> complex perovskite materials
Qiang Wang; Binglin Gu; Xiaowen Zhang; Qiang Wang; Dept. of Mater. Sci. & Eng., Tsinghua Univ., Beijing, China; Binglin Gu; Dept. of Mater. Sci. & Eng., Tsinghua Univ., Beijing, China; Xiaowen Zhang; Dept. of Mater. Sci. & Eng., Tsinghua Univ., Beijing, China
Журнал:
Journal of Physics: Condensed Matter
Дата:
1990-12-10
Аннотация:
Experimental observation of a (Pb<sub>1-x</sub>Ca<sub>x</sub>)TiO<sub>3</sub> complex perovskite ceramic near x=0.5 has suggested that the Pb and Ca atoms are ordered alternately on a particular A site (111) plane. Furthermore, a body-centred superlattice ordered structure has been observed in (Ba<sub>1-x</sub>Pb<sub>x</sub>)TiO<sub>3</sub> ceramic. In this paper, the eight-point cluster variation method, in which the second- and third-neighbour interactions are considered, has been employed to study these ordered structures and calculate the phase diagrams as a function of reduced temperature and composition for various interaction parameters. Theoretical results explained well the formation mechanism of these ordered structures.
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