Bond ionicity, lattice energy, bond energy and microwave dielectric properties of ZnZr(Nb1−xAx)2O8 (A = Ta, Sb) ceramics
Abstract
The dependence of microwave dielectric properties on the structural characteristics of ZnZr(Nb1−xAx)2O8 (A = Ta, Sb) (0 ≤ x ≤ 0.10) ceramics is investigated. All the compounds were prepared by a conventional solid-state reaction method and analyzed via multiphase structure refinement. The diffraction patterns of ZnZr(Nb1−xAx)2O8 (A = Ta, Sb) show the monoclinic wolframite structure of ZrZrNb2O8 which consists of an oxygen octahedron, with the Nb ion in the center of the oxygen octahedron. For the ZnZr(Nb1−xAx)2O8 (A = Ta, Sb) ceramics, the dielectric constant (εr) decreased with the decrease in Nb-site bond ionicity. The quality factor (Q × f) of ZnZr(Nb1−xSbx)2O8 ceramics was found to be the highest (89 400 GHz), which is explained in terms of the average of the Nb-site lattice energy. With the decrease in the bond energy of the Nb-site, the temperature coefficient of resonant frequency (|τf|) value increased. The substitution of A5+ (A = Ta, Sb) for Nb5+ effectively influences the microstructure and microwave dielectric properties of ZrZrNb2O8 ceramics.