Preparation, phase structure and microwave dielectric properties of CoLi2/3Ti4/3O4 ceramic

A new low loss microwave dielectric ceramic with composition of CoLi2/3Ti4/3O4 was prepared by a conventional solid-state reaction method. The compound has a cubic spinel structure [Fd-3m (227)] similar to MgFe2O4 with lattice parameters of a = 8.3939 Å, V = 591.42 Å3, Z = 8 and ρ = 4.30 g/cm3. This ceramic has a low sintering temperature (∼1050 °C) and good microwave dielectric properties with relative permittivity of 21.4, Q × f value of 35,000 GHz and τf value of −22 ppm/°C. Furthermore, the addition of BaCu(B2O5) (BCB) can effectively lower the sintering temperature from 1050 °C to 900 °C and does not induce much degradation of the microwave dielectric properties. Compatibility with Ag electrode indicates that the BCB added CoLi2/3Ti4/3O4 ceramics are good candidates for LTCC applications.