Dielectric responses and structure-property relationships of Ca1-xBaxWO4 composite microwave dielectric ceramics

Ca1-xBaxWO4 (x = 0-0.25, CBWO) composite microwave dielectric ceramics were obtained after sintering at 1200 C for 4 h. X-ray diffraction and X-ray photoelectron spectroscopy were used to determine their complex phase structures. The lattice vibrational properties were revealed by Raman scattering and Fourier -transform infrared (FTIR) spectroscopy. The Raman spectra showed that phase-pure CaWO4 had eight active vibrational modes when x = 0.15-0.25. A new vibrational mode appeared near 927 cm(-1), which was attributed to BaWO4. The intrinsic properties were fitted and simulated by the four-parameter semi-quantum model according to the FTIR spectra. The low-frequency vibrational modes made a greater contribution to the intrinsic properties than the high-frequency modes. Structure-property relationships of the CBWO ceramics were obtained using Raman spectroscopy, and their dielectric responses were elucidated. The CBWO ceramic at x = 0.25 had excellent dielectric properties with epsilon(r) = 7.43 and Q x f = 56,929 GHz. (C) 2022 Published by Elsevier B.V.

Automated summary

The complex phase structures, lattice vibrational properties, and intrinsic properties of Ca1-xBaxWO4 composite microwave dielectric ceramics were investigated. The structure-property relationships were obtained using Raman spectroscopy, and the excellent dielectric properties of the CBWO ceramic at x = 0.25 were elucidated.