Effects of Ga2O3 doping on the microstructure and dielectric properties of SrTiO3–SmAlO3 ceramics for microwave applications

• Published in: Ceramics international Vol. 50; no. 23; pp. 51782 - 51788
• Main Authors: Yao, Mengchen, Hao, Hua, Li, Dongxu, Wang, Zhen, Yao, Zhonghua, Cao, Minghe, Liu, Hanxing
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-12-2024
• Subjects: 0.4SrTiO3-0.6SmAlO3; Ga2O3 doping; Microwave dielectric properties; Ga2O3 doping; 0.4SrTiO3-0.6SmAlO3; Microwave dielectric properties
• ISSN: 0272-8842
• DOI: 10.1016/j.ceramint.2024.02.202

xSrTiO3-(1-x)SmAlO3 (ST-SA) (x = 0.4, 0.5, 0.6) microwave dielectric ceramics were prepared by solid-state reaction method and the microwave dielectric properties (εr, Q × f, τf) were studied. The 0.4ST-0.6SA component with better Q × f and τf was selected and the effects of different ywt % Ga2O3 (y = 0.5, 1.0, 1.5, 2.0, 2.5) doping on the phase structure, microstructure, and microwave dielectric properties of ceramics were investigated. X-ray diffraction analysis showed that Ga3+ mainly replaced Ti4+ site when y ≤ 0.5, and when y > 0.5, Ga3+ start to replace Al3+ site. The best grain uniformity of the ceramics was observed at y = 2.0 by scanning electron microscopy testing. Raman spectroscopy shows that the stability of the oxygen octahedron is improved after Ga2O3 doping with increased Q × f value. The change of Ga2O3 doping amount also affects the dielectric properties of ST-SA ceramics. The optimum Q × f value of the ceramic is improved by about 50% from 10,278 GHz (7.465 GHz, 0.4ST-0.6SA) to 15,712 GHz (6.950 GHz, 0.4ST-0.6SA-2.0 wt% Ga2O3) with improved dielectric properties (εr = 36.14，τf = 4.17 ppm/°C).