Dielectric relaxation behaviour of Bi:SrTiO3:: II.: Influence of heat treatment on dielectric properties

The study of the dielectric properties of (Sr1-1.5xBix)TiO3 ceramics in a range of temperatures and at several frequencies showed that a set of permittivity peaks situated around 200-300 K had frequency dispersion behaviour. These peaks were shifted to higher temperatures when the Bi content increased irt the solid solution. The activation energy calculated for the relaxation varied between 0.32-0.49 eV. This set of permittivity peaks vanished if the samples were annealed in air or oxygen and their permittivity maximum was increased by annealing in nitrogen. The temperature dependence of resistance rr ns also measured. The origin of dielectric behaviour is discussed in the present paper. (C) 1998 Elsevier Science Limited. All rights reserved.