Effect of MgO addition on the electrical transport properties of highly Sb-doped BaTiO3 ceramics

BaTiO3 ceramics doped with Sb donors and Mg acceptors have been fabricated. The lattice constant ratio c/a and the Curie point T-c decrease with increasing Sb concentration. The minimum room temperature resistivity rho(min) of the codoped BaTiO3 occurs at a composition of 0.9 mole% Sb2O3-1 mole % MgO as compared to the literature reported rho(min) at 0.3 mole % antimony for the Sb2O3-doped BaTiO3. The Mg2+ ion acts as an acceptor in the BaTiO3 ceramics, which compensates the donor contribution from Sb3+ and shifts the doped-BaTiO3 semiconducting region to higher antimony content. The calculated donor concentration confirms the compensation effect of Mg acceptors over Sb donors. The temperature dependence of both barrier height and dielectric constant of specimens is discussed. (C) 1998 Chapman & Hall.