Comment on ’’A systematic experimental and theoretical investigation of the grain-boundary resistivities of n-doped BaTiO3 ceramics’’

In a recent paper Ihrig and Puschert reported on measurements of the current-voltage characteristics and the temperature dependence of the effective zero resistivity of n-type ceramic BaTiO3. They described their results using Heywang’s potential-barrier model. In contradiction to other authors they denied a need to modify this model. It is shown here that the experimental results of Ihrig and Puschert are not detailed enough to warrant such a decision. The effect of an intergranular layer of a second phase on the grain-boundary resistance of ceramic BaTiO3 is briefly discussed.