One-step synthesis of Li2Mg2Mo3O12-(Li1/2Bi1/2)MoO4 composite ceramics with a stable temperature coefficient for ULTCC applications

Dielectric materials with near-zero τf values are needed to enhance the thermal stability of devices and ensure their stability during temperatures changes. In this study, the introduction of the (Li1/2Bi1/2)MoO4 phase was employed to regulate the τf of the Li2Mg2Mo3O12 system. A temperature-stable Li2Mg2Mo3O12-(Li1/2Bi1/2)MoO4 composite ceramics were successfully synthesized using a one-step direct synthesis approach for the first time. The synthesis involved controlling the Li2CO3 : MgO : Bi2O3 : MoO3 ratios at 1 : (2 − 1.5x) : x/2 : 3 (x = 0.02 – 0.30). The impacts of different x values on phase composition, sintering properties and microwave dielectric properties were investigated. X-ray diffraction and Roman spectroscopy revealed the coexistence of the two phases without other miscellaneous phases. When x = 0.15, the excellent microwave dielectric properties were obtained with samples sintered at 600 °C for 2 h: εr = 11.4, Q×f = 41,592 GHz (f = 11.2 GHz), τf = − 8 ppm/°C.