Crystal structure and microwave dielectric properties of Li₂(Mg_1–xCu_x)₂Mo₃O₁₂ ceramics sintered at ultra‐low temperature

Abstract

Li2(Mg1–xCux)2Mo3O12 (0 ≤x ≤0.1) ceramics were prepared using the conventional solid‐phase method to study the effect of the Cu2+ substitution for Mg2+ on the sintering behavior, crystal structure, and microwave dielectric properties of ceramics. The experimental results show that the substitution of Cu2+ for Mg2+ reduces the sintering temperature of the ceramics to 550°C. X‐ray diffraction patterns show that the introduction of Cu2+ does not produce a new phase, but rather promotes the formation of Li2(Mg1–xCux)2Mo3O12 solid solution. The microwave dielectric properties of the ceramics are influenced by the cell parameters, bond lengths, and structural stability. However, Cu2+ creates oxygen vacancies during sintering, thereby deteriorating the dielectric properties (Q × f decreases). The microwave dielectric properties of Li2(Mg1–xCux)2Mo3O12 ceramics are optimal at a sintering temperature of 550°C and x = 0.02, with εr = 9.17, Q × f = 7960 GHz, and τf = –58.77 ppm/°C. Additionally, these ceramics are compatible with Al electrodes.