Microwave dielectric properties, chemical bonds and infrared reflection spectra of La2Sn2O7 ceramics with pyrochlore structures

The La2Sn2O7 ceramic was synthesized using the solid−phase reaction method. The crystal structure, sintering characteristics, and microwave dielectric properties of the La2Sn2O7 ceramics were studied. XRD analysis shows that La2Sn2O7 ceramics possess a pyrochlore structure with a space group of Fd3¯m. As the sintering temperature increases, the εr and relative density show the same trend of change. The Q×f of ceramics has a strong correlation with the packing fraction. The P−V−L theory shows that La−O and Sn−O bonds have certain effects on the εr and Q×f. The intrinsic dielectric properties of ceramics were analyzed using infrared reflection spectra. At 1350 °C, La2Sn2O7 ceramic obtained the largest relative density and optimum microwave dielectric properties (εr = 15.65, Q×f = 73,804 GHz and τf = −18.58 ppm/°C).