Electrical properties of MgO-doped BaTiO3

Abstract

The defect chemistry of Mg-doped BaTiO₃ has been quantitatively studied. BaTi_1−xMg_xO_3−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%.