Effect of the Manganese Valence State on the Electrical Conductivity of Barium Titanate

The effect of defect structure on electrical conductivity for Mn-doped BaTiO3 at high temperatures was studied experimentally and theoretically. The measured conductivity was proportional to Po2−1/4 in the n-type region, and to Po2+1/6 in the p-type region in the temperature range between 900° and 1000°C. The results agree with calculations on the basis of the equilibrium equation for the valence change of Mn ions between tetravalent and trivalent. In the p-type region, the concentration of trivalent Mn ions decreases with Po2−1/6.