Crystal structure, infrared spectra and microwave dielectric properties of ultra low-loss Li2Mg4TiO7 ceramics

The low-loss Li2Mg4TiO7 dielectric ceramics were prepared by the conventional solid-state method. The relationship among sintering behavior, phase composition, microstructure and dielectric properties of Li2Mg4TiO7 ceramics was investigated. All the sintered samples exhibited the single phase with rock-salt structure belonging to Fm-3m space group. The higher Q.f values of samples above 1500 degrees C were depending on crystal structure and phase composition. IR reflectivity spectrum indicated that the dielectric constant of Li2Mg4TiO7 was mainly affected by the polar optical phonons. Typically, the ceramics sintered at 1600 degrees C exhibited excellent microwave dielectric properties with epsilon(r) = 13.43, Q.f = 233,600 GHz and tau(f) = -7.24 ppm/degrees C. (C) 2017 Elsevier B.V. All rights reserved.