Barium titanate (BaTiO3) based ceramics doped with La as donor (0.4at%t) and Mn as acceptor (150 ppm) were investigated through atomic force microscopy operating in electric force microscopy mode in order to reveal the potential barriers at grain boundaries. These barriers are associated with the steep rise in the resistivity above the ferroelectric-paraelectric phase transition temperature in BaTiO3 doped with small amounts of donor impurities. We show here that for such a composition the potential barrier width are of the order of 350-400 nm, present at grain boundaries of grains with size around 1 µm.
barium titanate; electric conductivity; potential barriers; PTC effect; atomic force microscopy; electric force microscopy
