Effect of A-site cation on crystal structure and microwave dielectric properties of AGe4O9 (A = Ba, Sr) ceramics. Issue 7 (July 2021)

• Record Type: Journal Article
• Authors: Li, Feihu; Tang, Ying; Li, Jie; Fang, Weishuang; Ao, Laiyuan; Wang, Yu; Zhao, Xiangguang; Fang, Liang
• Is Part Of: Journal of the European Ceramic Society. Volume 41:Issue 7(2021)
• Page Start: 4153
• Page End: 4159
• Publication Date: 2021-07
• Subjects: Microwave dielectric performance -- Ceramics -- Low-permittivity -- Rattling effect -- Infrared spectroscopy; Ceramic materials -- Periodicals; Composite materials -- Periodicals; Matériaux céramiques -- Périodiques; Composites -- Périodiques; Ceramic materials; Composite materials; Periodicals; Electronic journals; 666.05
• DOI: 10.1016/j.jeurceramsoc.2021.01.055
• Languages: English
• ISSNs: 0955-2219

Abstract

Abstract: AGe4 O9 (A = Ba, Sr) ceramics with hexagonal structure were fabricated by solid-phase reaction. BaGe4 O9 sintered at 1060 °C had low εr ∼9.8, high Q × f ∼78, 400 GHz and τf ∼ -44.2 ppm/°C, whilst SrGe4 O9 sintered at 1100 °C exhibited relatively high εr ∼11.2, low Q × f ∼62, 500 GHz and near-zero τf ∼ -11.7 ppm/°C. The τf of SrGe4 O9 was nearer to zero than that of BaGe4 O9 due to the smaller τε value and the smaller distortion of the [GeO6 ] octahedrons. The 'rattling' cations at A-site contribute to comparatively high εr, low Q × f and near-zero τf values in Sr1- x Ba x Ge4 O9 ceramics. This work presents a new idea of adjusting the microwave dielectric performance (MDP) of ceramics by changing the strength of the rattling effect at A-site.