Investigation on the Correlation between Structural and Electrical Properties of Lanthanum Doped Barium Titanate Ceramics

Abstract

The structure-property relationship of 0.3, 0.5 and 0.7mole% lanthanum (La 2 O 3 ) doped Barium titanate (BaTiO 3 ) ceramics prepared by solid state sintering under different sintering conditions were investigated in this research. The raw materials were La 2 O 3 (grain size=~80nm) and BaTiO 3 (grain size=100nm) powders. Field Emission Scanning Electron Microscope (FE-SEM) was used to examine grain size and surface morphology of sintered pellets & X-Ray Diffraction analysis was conducted to identify crystal structure. The results showed significantly improved grain size and electrical properties of BaTiO 3 for 0.5 mole% La 2 O 3 with desired grain size (0.8-1.3μm), high densification (>90% theoretical density) and stable dielectric constant (12700) at room temperature (f=100Hz) by lowering curie temperature around 30 o C by sintering at 1300 o C for 8 hrs. A gradual deterioration follows with increased doping concentration. So the research revealed that proper La 3+ concentration can inhibit grain size and lower Curie temperature hence significantly improving the electrical properties of BaTiO 3 ceramics.