Electronic structure, Raman spectra, and microwave dielectric properties of Co-substituted ZnWO4 ceramics

Abstract

The electronic structure, chemical bond characteristics and microwave dielectric properties of Zn1−xCoxWO4 (x = 0–0.1) ceramics prepared by solid-state reaction were investigated by First-principle calculations, Raman spectroscopy, XRD refinement and P-V-L theory. According to the P-V-L theory and electronic structure calculations, the bond energy and covalency of W-O were stronger than that of Zn-O, which played a crucial role in the properties. The Raman spectra illustrated that appropriate Co2+ substitution was beneficial to the ordered structure. Additionally, the relative permittivity of the sample was mainly affected by the porosity and ionic polarizability, and the quality factor is determined by the microstructure, bond energy and packing fraction, and the τf value is correlated with bond valence of W-O. This study showed how the Co2+ substitution not only reduces the dielectric loss and the signal delay time, but also improves the temperature stability. The composition (x = 0.02) exhibited remarkable properties: εr = 14.22, Q×f = 59,805 GHz, τf = −60.3 ppm/°C, providing a promising candidate for 5 G electronic equipment.