Investigations of dielectric properties of wolframite A0.5Zr0.5NbO4 ceramics by bond theory and far-infrared spectroscopy

In this study, intrinsic dielectric properties of monoclinic A(0.5)Zr(0.5)NbO(4) ceramics (A = Mn, Zn, Mg, Co, Ni) with wolframite structure were investigated by chemical bond theory, infrared and terahertz spectroscopy. According to bond theory, Zr-O bonds and A-O bonds with larger bond susceptibility values provide majority contributions to relative permittivity; while Nb-O bonds dominate the structural stability and oxygen polyhedron distortion. Intrinsic dielectric properties calculated via far-infrared reflectivity spectroscopy are close to experimental properties, which indicates that most of dielectric contributions come from absorptions of structural phonon oscillation and infrared modes of dielectric response in A(0.5)Zr(0.5)NbO(4) ceramics vary with A-site ions. Furthermore, intrinsic properties estimated by terahertz time domain spectra also testify the effectiveness of theoretical dielectric properties.