The dielectric relaxation of Nb-doped samples, at temperatures ranging from 500 to 900K, was investigated in order to understand the effect of a space charge in grain boundary layers. Dielectric relaxation phenomena were observed for all of the specimens, regardless of the Nb doping content. The permittivity maximum temperature shifted, and the permittivity peak height varied, with the Nb doping content. In order to study the effect of a space charge in the grain boundary, upon the dielectric relaxation, Bi ions were diffused along the grain boundary of a 0.6mol%Nb-doped specimen. It was found that the dielectric relaxation behavior changed with the diffusion of Bi. The relaxations could be explained in terms of the space charge, which was affected by defects, in grain boundary layers.

Influence of Grain Boundary Layers on the Dielectric Relaxation of Nb-Doped SrTiO3. S.H.Kim, H.Seon, J.G.Park, J.H.Park, Y.Kim: Japanese Journal of Applied Physics - 1, 1999, 38[8], 4818-23