Crystal structure, lattice vibrational characteristic, and dielectric property of Nd(Mg1/2Sn1/2)O3 ceramic

Nd(Mg1/2Sn1/2)O3 (NMS) ceramic was synthesized using a conventional solid-state reaction method. Crystal structure and morphology were investigated through X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. Lattice vibrational modes were obtained through Raman scattering and Fourier transform far-infrared reflection spectroscopy. The main phase is NMS with monoclinic P21/n1 symmetry proved by XRD. SEM shows sample is dense and well-crystallized ceramic. The Raman spectrum with active modes were fitted with Lorentzian function, then these modes were assigned and illustrated, respectively. For example, the highest wavenumber mode above 650 cm−1 is attributed to A1g-like mode that corresponds to the symmetric breathing of oxygen octahedra. The far-infrared spectrum with seven infrared active modes was fitted by using four-parameter semiquantum models to calculate intrinsic properties, which agree well with the data calculated from Clausius-Mosotti equation, as well as the relationship between the damping coefficient and the intrinsic loss. F2u(2) yielded the greatest contribution to dielectric constant and loss, which is primarily represented as the inverted translational vibration of NdMgO6 octahedron. A1g(Nd) Raman mode in A-site has an enormous effect on the dielectric loss. The imaginary and real parts of the dielectric constant were obtained with the Kramers-Krönig analysis.