Temperature Stable and Low Loss Microwave Dielectric Ceramics of Li2Mg3-xSrxTiO6

Abstract

Abstract In this paper, a series of Li2Mg3-xSrxTiO6 (x = 0, 0.02, 0.04, 0.06, 0.08) ceramics were prepared by the conventional solid-state reaction method. The effects of Sr2+ substitution on the structure, morphology and microwave dielectric properties of Li2Mg3TiO6 ceramics were investigated. The X-ray diffraction (XRD) results indicated that Li2Mg3TiO6 and SrTiO3 phases stably coexisted with each other and formed composite materilas. The appearance of porous structure mainly originated from the volatilization of lithium at high sintering temperatures. As the Sr2+ content increased from 0 to 0.08, the optimum dielectric constant (ε r ) increased from 13.61 to 17.32, the quality factor (Q×f) decreased monotonously and the temperature coefficient of resonant frequency (τ f ) changed from -34.4 to +16.8 ppm/°C. The variations of ε r , Q×f and τ f could be explained by the Lichtenecker logarithmic model and mixing rule, respectively. In particular, optimal microwave dielectric properties of ε r = 16.08, Q×f = 82100 GHz, τ f = +1.7 ppm/°C were obtained for Li2Mg2.94Sr0.06TiO6 ceramic sintered at 1310 °C for 5h.