Sintering characteristics, crystal structure, and microwave dielectric properties of non-stoichiometric BaMg2V2+xO8 (0.04 ≤ x ≤ 0.16) ceramics

BaMg2V2+xO8 (0.04 ≤ x ≤ 0.16) ceramics with high quality factors were prepared by the conventional solid-state reaction method at 850–925 °C, which can meet the LTCC technology. The effects of non-stoichiometric V5+ ions on sintering characteristics, phase composition, microstructure, as well as on microwave dielectric properties have been analyzed. All ceramic samples synthesized with different non-stoichiometric ratios of V5+ ions had a single tetragonal structure phase which belonged to the I41/acd (142) space group. The τf value of BaMg2V2+xO8 (0.04 ≤ x ≤ 0.16) ceramics was adjusted without deteriorating Q×f\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$Q \times f$$\end{document} value by adding excessive V5+ ions, and Q×f\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$Q \times f$$\end{document} value was found to correlate with relative density and the average lattice energy of V–O bonds while the τf value correlating with the total bond energy. The BaMg2V2.12O8 ceramics sintered at 900 °C showed an optimal Q×f\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$Q \times f$$\end{document} value of 141, 014 GHz, with εr\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\varepsilon_{{\text{r}}}$$\end{document} of 12.4 and τf of − 14.25 ppm/°C.