Effect of Strontium Doping on the Microstructures and Dielectric Properties of Lanthanum Titanate Ceramics

Abstract

Pure and Sr-doped lanthanum titanate ceramics were prepared by conventional solid state reaction method. The microstructures and dielectric properties of La2−xSrxTi2O7 (LSTO) (x = 0, 0.05, 0.1 and 0.2) ceramics were investigated. Results show that all the ceramics possess high relative density and a single phase. Strontium doping can refine the grains of ceramics and modify their microstructure; morphology of the grains changes from plate like to granular. The dielectric constants of LSTO ceramics initially increase and then decrease with increased strontium doping, whereas dielectric loss changes inversely. At 0.1% strontium doping, the optimum dielectric properties are obtained (εr = 122 and tanδ = 0.8%). Moreover, the dielectric constant basically has no variation with increased temperature and frequency.