Electrical properties of MgO-doped BaTiO₃

Abstract

The defect chemistry of Mg-doped BaTiO3 has been quantitatively studied. BaTi1−xMgxO3−x samples (x = 0, 0.001, 0.005, 0.01, 0.012, 0.02) have been precisely synthesized by the Pechini method. The concentration of oxygen vacancies was estimated from the location of the oxygen partial pressure P°(O2) at which the minimum point of equilibrium electrical conductivities occurs. Below 1.0 mol% Mg substitution for Ti sites, the experimental result is in good agreement with the theoretical calculation if the concentration of oxygen vacancies is assumed to be 100 ppm for undoped BaTiO3, where the oxygen vacancies stem from the background acceptor impurities. The solubility limit of Mg on Ti sites was confirmed to close to 1.0 mol%.