Electric state and crystal structure of corundum-type microwave dielectric ceramics with low dielectric loss

Abstract

The relationship between the chemical bonding of cation-oxygen bonds and microwave dielectric properties of Mg₄Nb₂O₉ compound and solid solutions was investigated in this study by using Rietveld analysis and molecular orbital calculation method. The results of molecular orbital calculation revealed that the covalency of cation-oxygen bond in NbO₈ octahedron increased by the Mn, Co, Ni and Zn substitutions for Mg, while that of cation-oxygen bond increased when Nb was substituted by Ta and Sb; the variations in the dielectric constant showed a similar tendency to those of covalency of cation-oxygen bonds in the MgO₈ and NbO₈ octahedra