Effect of Co2+ substitution on crystal structure and microwave dielectric properties of MgZrNb2O8 ceramics

Dense Mg1-xCoxZrNb2O8 (0 ≤ x ≤ 0.10) ceramics samples were prepared through solid-state reaction method. The influence of Co2+ substitution on phase composition, crystal structure and microwave dielectric properties were investigated systematically. Dielectric polarizability, packing fraction and bond valence were calculated respectively to investigate the correction with dielectric constant, quality factor and temperature coefficient of resonant frequency. Especially, optimal microwave dielectric properties with εr = 25.18, Q × f = 70709 GHz, τf = −46.09 ppm/°C were obtained for the sample of Mg0.98Co0.02ZrNb2O8 sintered at 1260 °C for 4 h.