GRAIN-SIZE EFFECTS ON DIFFUSE PHASE-TRANSITIONS OF SOL-GEL PREPARED BARIUM-TITANATE CERAMICS

Barium titanate ceramic samples, obtained by sol-gel methods, having d ifferent grain sizes have been analyzed by diffuse phase transition te chniques. We performed a study of the influence of each method on the phase transition interval and on the Landau parameters of the ferroele ctric phase transition of these materials. The results show the existe nce of a relationship between the diffuse character of the transition and the grain size of the sample. The method of fitting dielectric dat a presented here allows us to compare ceramics with single crystals an d then analyze the sol-gel process used to obtain them.