Microwave dielectric properties of Li3Mg2NbO6-based ceramics with (MxW1-x)5+(M = Li+, Mg2+, Al3+, Ti4+) substitutions at Nb5+sites

Li3Mg2Nb0.96 (MxW1-x)(0.04)O-6 (M = Li+, Mg2+, Al3+, Ti4+) ceramics were prepared by the solid-state reaction method. The sintering characteristics, microstructure, phase composition and microwave dielectric properties of Li3Mg2NbO6 ceramics with equivalent substitution ((Li1/5W4/5)(5+), (Mg1/4W3/4)(5+), (Al1/3W2/3)(5+) and (Ti1/2W1/2)(5+)) at the Nb-site were investigated firstly. After sintering at 1150 degrees C for 4 h, all samples were single-phase of orthogonal structure. Due to the difference in ion polarizability of the substituted ions, the dielectric constant changed. The substitution of (MxW1-x)(5+) in Li3Mg2Nb0.96 (MxW1-x)(0.04)O-6 ceramics significantly reduced dielectric loss. The quality factor showed a similar trend with the average bond valence. Moreover, the study found that the substitution of W-based composite ions has a small effect on the tau(f) values of Li3Mg2NbO6 ceramics. (C) 2020 Elsevier B.V. All rights reserved.