Size effect on the dielectric properties of BaTiO3 nanoceramics in a modified Ginsburg-Landau-Devonshire thermodynamic theory
Size effect on the dielectric properties of BaTiO3 nanoceramics in a modified Ginsburg-Landau-Devonshire thermodynamic theory
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DOI：
10.1103/physrevb.74.134115
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发表时间：
2006-10-01
影响因子：
3.7
通讯作者：
Wang, Xiaohui
中科院分区：
文献类型：
--
作者：
Lin, Shan;Lu, Tianquan;Wang, Xiaohui
利用改进的 Ginsburg-Landau-Devonshire (GLD) 热力学理论研究了晶粒尺寸对 BaTiO3 纳米陶瓷介电性能的影响。考虑到内应力的存在，发现随着晶粒尺寸的减小，立方-四方相的转变温度降低，而四方-斜方和斜方-菱面体相的转变温度则升高。随着晶粒尺寸的进一步减小，我们的模型预测，正交相和四方相的两种铁电结构将变得不稳定并在临界尺寸处消失，只留下菱方结构的一种稳定的铁电相。因此，建立了转变温度与晶粒尺寸的理论相图，其中指示了两个三相点和重入行为。结果与实验数据进行了比较。
Grain size effects on the dielectric properties of BaTiO3 nanoceramics have been studied by using the modified Ginsburg-Landau-Devonshire (GLD) thermodynamic theory. Considering the existence of internal stresses, it is found that with decreasing grain size the transition temperature of cubic-tetragonal phase decreases, while those of tetragonal-orthorhombic and orthorhombic-rhombohedral phases increase. With further reducing grain size, our model predicts that the two ferroelectric structures of orthorhombic and tetragonal phases will become unstable and disappear at a critical size, leaving only one stable ferroelectric phase of rhombohedral structure. Consequently, a theoretical phase diagram of the transition temperature versus grain size is established wherein two triple points and a reentrance behavior are indicated. The results are compared with experimental data.