Layered-perovskite Ca1-Ba La4Ti5O17 microwave dielectric ceramics with medium dielectric constant

作者：Xiaohui Zhang, Xiaohua Zhang, Xiaohua Zhang, Xiaohua Zhang, Shuai Ma, Xingyuan Qi, Zhenxing Yue · 发表于：Ceramics International · 年份：2024 · DOI：10.1016/j.ceramint.2024.02.062 · 被引用次数：10 · 研究领域：Microwave Dielectric Ceramics Synthesis、Ferroelectric and Piezoelectric Materials、Layered Double Hydroxides Synthesis and Applications

The layered perovskite Ca 1- x Ba x La 4 Ti 5 O 17 ( x = 0.2, 0.4, 0.6, 0.8) compounds were synthesized via the solid-state reaction method, and their phase composition, microstructure and microwave dielectric properties were investigated. X-ray diffraction (XRD), Raman spectroscopy and selected area electron diffraction (SAED) patterns confirmed that it appears as a single phase with orthorhombic perovskite structure belonging to the Pnnm space group when x = 0.2. The crystal structure analysis and high-resolution transmission electron microscope (HRTEM) results showed that the compound has a layered structure composed of 5 unit [TiO 6 ] layers tightly packed (A n B n O 3 n +2 , n = 5). The Q×f value of ceramics was gradually improved with the increase of Ba 2+ content, which was attributed to the production of the second phase BaLa 2 Ti 3 O 10 , but it also caused the deviation of the temperature coefficient of resonant frequency (τ f ). For the ceramic specimen of x = 0.2, excellent microwave dielectric properties were obtained with an optimal combination ( ε r = 57.2, Q×f = 12,100 GHz, and τ f = 0.67 ppm/°C). Ba-modified CaLa 4 Ti 5 O 17 ceramics with comprehensive and excellent performance provides support for miniaturized microwave device applications.