Microwave dielectric properties of scheelite structured low temperature fired Bi(In_1/3Mo_2/3)O₄ ceramic

A Bi(In_1/3Mo_2/3)O₄ ceramic was prepared via the solid state reaction method. The pure monoclinic phase was formed at around 650 °C. Ceramic samples with relative densities above 97% were obtained when sintering temperature was around 840 °C. The best microwave dielectric properties were achieved in the Bi(In_1/3Mo _2/3)O₄ ceramic sintered at 840 °C for 2 h with permittivity ∼25.2, Qf of 40,000 GHz and temperature coefficient of resonance frequency ∼-65 ppm/°C at 8.2 GHz. The temperature dependence of microwave dielectric properties was also studied in a wide temperature range from -250 °C to +120 °C. The Qf value increased with the decrease of temperature and reached a maximum of 150,000 GHz at -250 °C.