Preparation, phase structure and microwave dielectric properties of a new low cost MgLi2/3Ti4/3O4 compound

A novel Li-based spinel compound with the composition of MgLi2/3Ti4/3O4 was synthesized by the conventional solid-state reaction method. The phase structure was studied by X-ray diffraction (XRD) technique. When the calcination temperature was over 1050 °C, a single phase compound which has a cubic structure [Fd-3m (227)] with cell parameters of a = 8.4057 Å, V = 593.91 Å3, ρ = 3.51 g cm−3 and Z = 8 was obtained. MgLi2/3Ti4/3O4 ceramic could be well densified after sintering above 1125 °C. The microwave dielectric properties were measured using a microwave vector network analyzer in the frequency range of 7–9 GHz MgLi2/3Ti4/3O4 ceramic sintered at 1125 °C for 2 h showed microwave dielectric properties of ɛr = 20.2, Q × f = 62,300 GHz, and τf = −27.1 ppm °C−1. Furthermore, 0.95MgLi2/3Ti4/3O4–0.05CaTiO3 ceramic sintered at 1200 °C for 2 h exhibited good properties of ɛr = 22.6, Q × f = 48,000 GHz, and τf = −2.3 ppm °C−1.