DIELECTRIC-RELAXATION BEHAVIOR OF BI-SRTIO3 - III - DIELECTRIC-PROPERTIES IN THE TEMPERATURE-RANGE OF 300-600 K

(Sr1-1.5xBix)TiO3 ceramics show several polarisation and conduction me chanisms in different temperature ranges. bl the present paper, the pe rmittivity peaks that occur-red in the temperature range from 300 to 6 00 K are discussed for the samples both as-sinter ed and O-2 or N-2 an nealed. The activation energy for conduction in the temperature range in which these permittivity peaks occurred is around 0.59-0.78 eV. Thi s suggests that the carriers responsible for the conduction are coming from the thermal excitation of electrons from the V-0(.) state to the conduction band. The activation energy for dielectric relaxation is i n the range of 0.64-086 eV. The discussion on the cor relation between dielectric relaxation and conduction, led to suggest that the permitt ivity peaks are related to a dipole-like dielectric relaxation either for the as-sintered samples aswell as for the ones annealed in O-2. Ho wever, for the samples annealed in Nz, the results indicate that the p olarisation mechanism is related to the trap-controlled ac conduction. (C) 1998 Elsevier Science Limited. All rights reserved.