Effects of (Mg1/3Sb2/3)(4+) substitutions on the sintering behaviors and microwave dielectric properties of Li2Mg4Zr1-x(Mg1/3Sb2/3)(x)O-7 ceramics

In this work, a series Li2Mg4Zr1-x(Mg1/3Sb2/3)(x)O-7 (x = 0.10-0.25) ceramics were synthesized using the classical solid-state reaction method. The effects of (Mg1/3Sb2/3)(4+) in the microstructures, sintering behaviors, and microwave dielectric properties of Li2Mg4Zr1-x(Mg1/3Sb2/3)(x)O-7 ceramics were investigated systematically. XRD analyses indicate that all samples were the rock-salt structure with the Fm-3m space group, the crystalline parameters were obtained using the Rietveld refinement. Based on the complex chemical bond theory, the effects of inherent features (e.g. bond ionicity, bond energy, and lattice energy) on the dielectric performance of Li2Mg4Zr1-x(Mg1/3Sb2/3)(x)O-7 ceramics were analyzed in details. By adding proper content of (Mg1/3Sb2/3)(4+), the optimal dielectric performance of epsilon(r) = 12.29, Q x f = 153,140 GHz, and tau(f) = -17.7 ppm/degrees C were obtained in the Li2Mg4Zr0.8(Mg1/3Sb2/3)(0.2)O-7 materials at 1600 degrees C for 4 h. The quality factor is more than 100 THz, which indicates that the Li2Mg4Zr0.8(Mg1/3Sb2/3)(0.2)O-7 ceramic is a good candidate for the highly selective filters or microwave resonators. (C) 2021 Elsevier B.V. All rights reserved.