Relationship between structure and microwave dielectric properties of Li3Mg4Nb1-xTaxO8 ceramics

Herein, the sintering behavior and dielectric properties of Ta5+-doped Li3Mg4NbO8 ceramics were investigated by solid-phase reactions in combination with first-principles calculations. In particular, Li3Mg4Nb0.96Ta0.04O8 illustrates the best dielectric properties after sintering at 1,175 degrees C with er = 13.71 +/- 0.20, Q x f = (132,112 +/- 2,391) GHz (increased by 25%) and Tf = (25.07 +/- 1.36) x 10-6 degrees C-1. The non-intrinsic factors reflect that a small amount of Ta5+ doping produces a secondary phase, increased densification, and grain size, all of which optimize the dielectric properties. The dominant intrinsic factors indicate that the increase in bond ionicity, the greater polarization of Ta5+, and the blueshift of the Raman characteristic peak all lead to an increase in er. The increase in lattice energy and the decrease in the damping behavior of the Nb/Ta-O bond vibrations lead to an increase in Q x f. The weakening of the Nb/TaO6 octahedral distortion leads to an optimization of Tf. The modified Li3Mg4Nb0.96Ta0.04O8 ceramics have promising applications in microwave communications. (c) 2023 The Authors. Published by Elsevier B.V. on behalf of The Chinese Ceramic Society. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).