Dielectric relaxation behaviour of Bi:SrTiO3:: III.: Dielectric properties in the temperature range of 300-600 K

(Sr1-1.5xBix)TiO3 ceramics show several polarisation and conduction mechanisms in different temperature ranges. bl the present paper, the permittivity peaks that occur-red in the temperature range from 300 to 600 K are discussed for the samples both as-sinter ed and O-2 or N-2 annealed. The activation energy for conduction in the temperature range in which these permittivity peaks occurred is around 0.59-0.78 eV. This 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 in the range of 0.64-086 eV. The discussion on the cor relation between dielectric relaxation and conduction, led to suggest that the permittivity peaks are related to a dipole-like dielectric relaxation either for the as-sintered samples aswell as for the ones annealed in O-2. However, for the samples annealed in Nz, the results indicate that the polarisation mechanism is related to the trap-controlled ac conduction. (C) 1998 Elsevier Science Limited. All rights reserved.