Correlation between crystal structure, bond characteristics, Raman vibrations, and improved microwave dielectric properties of high-performance Zn0.5Zr0.5NbO4 ceramics: First principle calculation and experiment

Abstract

The structure–performance mechanism provides new insights into performance modification and materials discovery. Herein, the electronic structure, Raman vibration, chemical bond factors and enhanced microwave dielectric properties of Zn0.5Zr0.5NbO4 ceramics through oxygen-assisted reaction sintering were investigated by Raman spectroscopy, first-principle calculations, and complex P–V-L theory. Pure-phase Zn0.5Zr0.5NbO4 ceramics were synthesized under oxygen-assisted reaction sintering, confirmed by XRD refinement and Raman analysis. Systematic vibration analysis was first introduced to provide complete mode assignments and Raman shift. Optimized microstructure with full density was obtained through morphology and EDS analysis. First-principle calculations indicated that the d orbit exerts the main contribution to Fermi energy with energy gap of 3.51 eV and Nb–O bonds may possess strong vibration, exhibiting a remarkable effect on dielectric loss. P–V-L results showed that Nb–O bonds have a significant influence on the dielectric constant and Q×f value while the Zn–O bonds dominate the τf value. In addition, high-performance Zn0.5Zr0.5NbO4 ceramics were fabricated through oxygen-assisted reaction sintering at 1250 °C, with εr = 28.4, Q×f = 79,800 GHz, and τf = −47.7 ppm/°C, exhibiting tremendous superiorities for commercial production.