材料科学
电介质
微观结构
溶胶凝胶
微晶
薄膜
旋涂
分析化学(期刊)
钛酸钡
四方晶系
钙钛矿(结构)
水溶液
结晶学
晶体结构
复合材料
化学
纳米技术
物理化学
有机化学
冶金
光电子学
作者
Burtrand Lee,Jianping Zhang
标识
DOI:10.1016/s0040-6090(01)00816-1
摘要
A highly stable, water-based BaTiO3 sol system was developed by a chelate acetate sol–gel process. The BaTiO3 thin films and powders were prepared by a spin coating and drying-firing method, respectively, from the aqueous BaTiO3 sol. Structural evolution of the BaTiO3 gel was investigated by X-ray diffraction, Fourier transform infrared spectroscopy, and thermal gravimetric analysis/differential thermal analysis. Scanning electron microscopy microstructure results showed that the BaTiO3 thin films consisted of nano polycrystallites with a grain size of 30–60 nm, possessing a cubic perovskite structure. With ultraviolet light (UV) irradiation, the BaTiO3 films could be crystallized to a cubic phase at 550°C. The dielectric measurement indicated no phase transition at the Curie temperature (125°C). It is believed that the small crystallites having a cubic perovskite structure are responsible for the low dielectric constant and the flat temperature coefficient of capacitance behavior is due to the lack of the phase transition from the tetragonal to cubic phase.
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