Rietveld refinement on BaTiO3 materials doped with MgO/Y2O3 additives

The microstructural and structural characteristics of BaTiO3 ceramics doped with MgO and Y2O3 additives were studied using SEM and Rietveld refinement, respectively. Incorporation of MgO and Y2O3 species markedly modify the grain size and the lattice parameter of the BaTiO3 materials, which correlate very well the site occupancy behavior of the Mg- and Y-dopants. While the Mg2+-ions only occupy B-site lattice, the site occupancy of Y3 +-ions change with the doping level. The Y3+-ions be only occupying A-site lattice in lightly-doped (Y2O3 <= 0.6 at.%) BaTiO3, and they occupy simultaneously both of the A- and B-site when the Y2O3 content exceeded 0.6 at.% in BaTiO3. Moreover, too abundant MgO (>= 2.0 at.%) addition increases the volume fraction of pseudo-cubic phase of BaTiO3 at room temperature.