Lattice vibrational characteristics, crystal structures and dielectric properties of non-stoichiometric Nd(1+x)(Mg1/2Sn1/2)O3 ceramics

Non-stoichiometric Nd(1+x)(Mg1/2Sn1/2)O-3 (-0.04 = x <= 0.04, NMS) ceramics were fabricated via a conventional solid-state reaction method. Crystal structures and morphologies were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The main crystalline phase is monoclinic Nd(Mg1/2Sn1/2)O-3 with a double perovskite structure (P2(1)/n space group) for the NMS system proved by XRD. The sample at x = 0.01 has the best crystallinity and evenly distributed crystal grains observed by SEM. The optimum performances (epsilon(r) = 19.87, Qxf = 41840 GHz, f = 12.05 GHz) are obtained at x = 0.01. Lattice vibrational modes of the Raman spectra were assigned and illustrated, in detail. The dielectric properties obtained by fitting infrared reflectance spectra with the help of four-parameter semi-quantum model are consistent with the calculated values by microscopic polarization and damping coefficients. The reverse translational vibration of the Nd-MgO6, the F-5u((5)) mode, provides the greatest contribution to the dielectric response. The relationships between crystal structures and dielectric properties were mainly established using lattice vibrational modes as a media. (C) 2020 The Chinese Ceramic Society. Production and hosting by Elsevier B.V.