Effects of Cu2+substitution on the sintering behavior, crystal structure and microwave dielectric properties of Li3Mg4NbO8 ceramics

In this work, the preparation of Li3(Mg4-xCux)NbO8 (0.01 <= x <= 0.04) was accomplished using the solid-state reaction method. Based on Rietveld refinement, microscopic morphology, and the complex chemical bonding theory, the influence of Cu2+ introduction on the microwave dielectric properties of Li3Mg4NbO8 ceramics was investigated, revealing the relationship between crystal structure and dielectric properties. The er was affected by both the relative density and ionic polarizability. A moderate amount of Cu2+ (x = 0.02) substitution for Mg2+ increased the lattice energy, which could enhance the Q x f value. Additionally, the of value also moved towards near zero because of the improvement in Nb-O6 octahedral distortion. Outstanding dielectric properties were achieved for Li3(Mg3.98Cu0.02)NbO8 ceramics at 1075 degrees C: er -13.59, Q x f -115,444 GHz, of --11.19 ppm/degrees C. Compared to pure Li3Mg4NbO8 ceramics, its Q x f value increased by 11.6%, and of increased by 68.9%.