Effect of cerium on the dielectric and structural properties of barium titanate-based ceramics for multilayer ceramic capacitors

Cerium-doped BaTi1-xCexO3 (x = 0.0, 0.15, 0.25) ceramics were synthesized using the sol-gel auto-combustion technique. An appropriate amount of the chemicals was dissolved in 100ml of distilled water in stoichiometric ratios to form an aqueous solution. The fine barium titanate precursor was pre-calcinated in a digitally controlled muffle furnace at 900°C for 5h. X-ray diffraction (XRD) pattern of the samples indicates that the calcined samples present the formation of a tetragonal crystal structure of BaTiO3. The diffraction peaks tend to have cubic symmetry due to Ce doping. The unit cell volume increases rapidly due to Ce doping This is attributed to the substitution of Ce ions at Ti sites, Fourier Transform Infrared Spectroscopy (FTIR) shows a strong absorption peak for pure BT powder is obtained at 484cm-1 , 485cm-1 and 487cm-1 for (x = 0.0, 0.15, 0.25) respectively, hence the bond energy increases with increase in doping concentration. The Field Emission Scanning Electron Microscopy (FESEM) and Energy Dispersive Spectroscopy (EDX) prepared at 1,100oC for 5 h show a homogeneous particle size of about 50.77nm and 75.87nm for x = 0.00 and 0.25, respectively. With Ce doping, a more homogeneous grain size evolved with an increase in average grain size and density with an increase in Ce doping concentration. The EDX spectra show the presence of Ba, Ti, Ce, and O. The result confirms that pure barium titanate is a dominant phase. There is an enhancement in the dielectric constant in the sample with the highest amount of Cerium (x= 0.25) characteristic of the copper sample, which is a good material for Multilayer ceramic capacitors.