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

The effect of defect structure on electrical conductivity for Mn‐doped BaTiO 3 at high temperatures was studied experimentally and theoretically. The measured conductivity was proportional to P o2 −1/4 in the n ‐type region, and to P o2 +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 P o2 −1/6 .