  Impedance measurements have been performed on a sintered polycrystalline
sample of the perovskite LaBiMn4/3Co2/3O6. Colossal dielectric permittivity
often is measured in this class of semiconducting materials as a result of
extrinsic factors. Our results show that a large offset in the capacitance,
measured on a series of samples with different thickness, is due to the
interfacial polarization. This contribution then can be removed from the data,
creating a general procedure for dielectric measurements in semiconducting
samples.
