Microstructure and Electrical Properties of Chemically Prepared Nb ₂ O ₅ ‐Doped SrTiO ₃ Ceramics

Abstract

Chemically homogeneous SrTiO 3 powders of submicrometer size were obtained by alcohol dehydration and subsequent calcination of citrate/format solutions. Nb 2 O 5 ‐doped SrTiO 3 was prepared with various Sr:Ti ratios resulting in an anomalous increase in the dielectric constant ( K ’up to ∼8000) for donor‐doped SrO‐excess SrTiO 3 . No semiconducting behavior was observed for donor‐doped TiO 2 ‐excess SrTiO 3 when fired in air. Therefore, a “brick‐wall” type of microstructure was formed as a result of the excess SrO, giving rise to anomalously high dielectric constants.