Structural characteristics and dielectric properties of Ti4+-substituted Li2Mg3SnO6 ceramics

Abstract To analyze the impacts of intrinsic factors on the dielectric properties, LiF was introduced to eliminate impurity phase Mg2SnO4, and a set of Li2Mg3Sn1-xTixO6-4 wt.% LiF (x = 0.0–1.0) ceramics were prepared by the solid-state reaction method. The XRD and SEM results indicated that all the compositions displayed a pure cubic phase (space group: Fm-3m, 225) and compact microstructure with increasing Ti4+ concentration, accompanied by a decrease in the average crystallite size from 2.54 μm to 1.92 μm. Based on the chemical bond theory and refinement data, several structural factors were determined to evaluate the relationship between the structural characteristics and dielectric properties. The increase in the dielectric constant (er) was ascribed to the improved average ionic polarizability αth/Vm. The trend of the change in the quality factor (Q × f) was closely related to the packing fraction and lattice energy. Additionally, the temperature coefficient of the resonant frequency (τf) changed within a narrow range, which could be attributed to the minor deviation in the octahedron bond energy. These results demonstrated that structural characteristics are key factors influencing the dielectric properties.