Point defect chemistry of donor-doped bismuth titanate ceramic

This communication reports on the defect chemistry at room temperature of barium (Ba) doped bismuth titanate (Bi ₄ Ti ₃ O ₁₂ ), emphasizing the influence of the point defects on its electrical properties. Pure and Ba doped Bi ₄ Ti ₃ O ₁₂ were prepared by a conventional solid-phase reaction technique. The addition of Ba into the crystal structure of Bi ₄ Ti ₃ O ₁₂ was monitored by X-ray diffraction measurements combined with Rietveld refinement studies where it was determined that Ba occupies the bismuth (Bi) lattice sites as well as the presence of oxygen vacancies (VO∙∙). The characterization of the point defects was carried out using impedance and electron spin resonance spectroscopies where the results support the models of compensation mechanisms dominated by electrical positive charges (h ^∙ ) and oxygen vacancies (VO∙∙).