Intrinsic dielectric properties and vibration characteristics of La(Mg_1/2Sn_1/2)O₃ ceramic

La(Mg_1/2Sn_1/2)O₃ (LMS) ceramic was synthesized via the conventional solid-state reaction method. The main phase of the sample is LMS with a double perovskite structure (monoclinic P121/n1 symmetry), which is confirmed by X-ray diffraction. Scanning electron microscopy shows the sample is well-crystallized with dense and uniform grains as well as clear grain boundaries. The Raman scattering and Fourier transform far-infrared reflection spectroscopies were employed to analyze the lattice vibrational modes of the sample. The Raman active modes were fitted by the Lorentz function, and the lattice vibrational modes were assigned and illustrated accurately. The four-parameter semiquantum model was applied to simulate the intrinsic dielectric properties, which agree well with the data calculated from the microscopic polarizability & damping angles. The A_1g(La) Raman mode in A-site has a great impact on the dielectric loss, and F_3u⁽²⁾ mode makes the largest contribution to the dielectric constant and the dielectric loss.