Doping mechanisms and electrical properties of La-doped BaTiO3 ceramics

Abstract

The electrical properties of Ba_1−xLa_xTi_1−x/4O₃ ceramics where x≤0.20 were investigated by impedance spectroscopy after heat treatment in O₂, Ar and air at 1350°C. Samples heated in O₂ were electrically insulating with very high maximum permittivities, ∼25,000 at x=0.06 and exhibited significant ‘relaxor-type’ behaviour at x=0.10. Samples heated in Ar were semiconducting for all x whereas air heated samples were electrically inhomogeneous. Semiconductivity in these materials is attributed to oxygen loss as opposed to La-donor doping.