A novel ultralow-loss Sr2CeO4 microwave dielectric ceramic and its property modification

Abstract

A new ultralow-loss Sr2CeO4 microwave dielectric ceramic was prepared via a conventional solid-state method. The X-ray diffraction and Rietveld refinement results demonstrate that pure-phase Sr2CeO4 ceramics belong to the orthorhombic structure with a Pbam space group. Scanning electron microscopy analysis reveals dense and homogeneous microstructure. Optimum microwave dielectric properties of εr = 14.8, Q × f = 172,600 GHz (9.4 GHz) and τf = -62 ppm/°C were obtained as it was sintered at 1270 °C for 4 h. In addition, the substitution of a few amount of Ti4+ for Ce4+ was found to have significant influences on the grain morphology, sintering behavior, phase structure and microwave dielectric properties. Among them, the Sr2Ce0.65Ti0.35O4 ceramic sintered at 1350 °C for 4 h demonstrates near-zero τf of -1.8 ppm/°C, εr of 20.7 and Q×f of 115,550 GHz (8.1 GHz) because of its two-phase structure, showing large application potentials.