Grain Boundary Defect Chemistry of Acceptor‐Doped Titanates: Space Charge Layer Width

The grain boundary space charge depletion layers in acceptor‐doped SrTiO 3 and BaTiO 3 ceramics were investigated by impedance spectroscopy in the time and frequency domain. Based on the layer width and its dependence on the acceptor concentration, the temperature, and the oxygen partial pressure during annealing, a suggestion for a refined Schottky model is proposed. The local distribution of the donor‐type grain boundary states causing the depletion layer and the resulting band bending are discussed.