Crystal structure and microwave dielectric properties of MgZr1-xSnxNb2O8 ceramics

Pure phase MgZr1-xSnxNb2O8 (x = 0, 0.1, 0.15, 0.2, 0.25 and 0.3) ceramics were first synthesized through conventional solid-state method. The theoretical dielectric polarizabilities, packing fractions and bond valences of MgZr1-xSnxNb2O8 ceramics were calculated in order to investigate the correlation between the crystal structure and microwave dielectric properties. A small amount of Sn4+ substituted for Zr4+ effectively improved the quality factor, but excessive substitution is not conducive to the improvement of Q x f value. Excellent microwave dielectric properties of epsilon(r) = 24.91, Q x f = 94,014.2 GHz, tau(f) = -43.93 ppm/degrees C were obtained for the MgZr1-xSnxNb2O8 ceramics with x = 0.15 sintered at 1260 degrees C.