Compensation Effect in Semiconducting Barium Titanate

Abstract

Donor‐doped, stoichiometric BaTiO 3 sintered at 1350°C for 1 h exhibits a maximum room‐temperature conductivity at [La 3+ ]∼0.15 mol%. Elements of lower valence than Ba 2+ or Ti 4+ , when incorporated into semiconducting BaTiO 3 , are regarded as poisoning impurities, i.e., acceptors. They tend to increase the room‐temperature resistivity of the semiconducting BaTiO 3 . For insulating BaTiO 3 resulting from high Mg 2+ acceptor doping levels, the semiconductivity can be restored by introducing higher La 3+ donor‐dopant concentrations. This behavior is interpreted as a compensation effect based on the defect chemistry of the acceptor‐ and donor‐doped BaTiO 3 .