Impact of Carbon Contamination on the Low-Temperature Electric Conduction of the Spark-Plasma Sintered Barium Titanate Ceramics

Abstract: The dielectric and electric conduction properties of BaTiO3 samples fabricated by the spark plasma sintering with additional contamination by different content of carbon have been investigated in the temperature range from 77 through 408 K in small non-heating electric fields and in the range of 77 - 200K under strong electric fields up to 20 kV/cm. The effective dielectric permittivity of the samples with additional carbon achieves colossal values at low frequency, up to several units per 106 at 393 K. In the low temperature range, it remains very high magnitude, 10^4 -10^5 at low frequency and is strongly dependent on the carbon content. The electric conduction in the range of 77 - 200 K bears the hopping conduction and obeys the Mott law. We also studied electric conduction and effective dielectric permittivity vs electric field strength in the range of 77 - 200 K. The results are explained within the frames of hopping conduction theory and suggestion on different constituents in polarization processes and electric conduction.