Preparation, characterization, and dielectric properties of wolframite-structure MnZrNb2O8 ceramics at microwave frequency

Abstract

The MnZrNb2O8 ceramics with a monoclinic wolframite crystal structure were prepared through the solid-state method and the microwave dielectric properties were also investigated systematically as a function of sintering temperatures. The trend of εr was similar to those of apparent density and shrinking ratio. When the sintering temperature was below 1250 °C, the Q·f value mainly depended on the density. However, when the sintering temperature was higher than 1250 °C, the Q·f value mainly depended on the crystal structure. All the τf values were fluctuated around −36.88 ppm/°C, ranging from −21.82 to −52.11 ppm/°C. Moreover, the theory of the bond energy was firstly used to predict the variation of the τf values. The ceramic sintered at 1250 °C for 4 h exhibited the excellent dielectric properties of εr = 24.62, Q·f = 27,936 GHz and τf = −52.11 ppm/°C. The relatively low sintering temperature and high dielectric properties would make these ceramics promising for applications in electronics.