Crystal structure, lattice vibrational characteristics, and dielectric properties of Ba(Mg1/2Mo1/2)O3 ceramics sintered at different temperatures

Abstract

Double perovskite structured Ba(Mg1/2Mo1/2)O3 (BMM) ceramics were prepared by traditional solid sintering methods at different sintering temperatures (Ts=1250–1325 °C). X-ray diffraction (XRD) data proved a 1:1 ordered face-centered cubic lattice (Fm-3 m), and the ceramic sintered at 1300 °C obtained maximum relative density. The lattice vibration characteristics were identified by Raman spectroscopy and far-infrared reflection spectroscopy. Based on the far-infrared data, a four-parameter semi-quantum model (FPSQ) was applied to calculate the intrinsic properties of BMM ceramics, and the obtained results approximated the measured values. The Raman shift of the BMM F2g(B) mode (attributed to the centrosymmetric vibration of Ba atom) was shown to be negatively correlated with the corrected permittivity and Ba-O bond length. With increasing sintering temperature (Ts), the relative density is positively correlated with the quality factor (Q × f), and the change of Ba-O bond length leads to distortion of the oxygen octahedron, which is positively correlated with the dielectric constant. The sintered BMM ceramics obtained their best dielectric properties at 1300 °C (εr= 4.987, Q × f = 23,069 GHz, f = 11.16 GHz).