Electrical Conduction in β‐Bi2O3 Doped with Sb2O3

Abstract

Electrical conduction in tetragonal β‐Bi2O3 doped with Sb2O3 was investigated by measuring electrical conductivity, ionic transference number, and Seebeck coefficient. The β‐Bi2O3 doped with 1 to 10 mol% Sb2O3 was stable up to 600°C and showed an oxygen ionic and electronic mixed conduction, where the electron conduction was predominant at low oxygen pressures. The oxygen‐ion conductivity showed a maximum at 4 mol% Sb2O3, whereas the activation energy for the ionic conduction remained unchanged for 4 to 10 mol% Sb2O3‐doped specimens. These results were interpreted in terms of the oxygen vacancy concentration and the distortion of the tetragonal structure. The electron conductivity and its oxygen pressure dependence decreased with increasing Sb2O3 content. The fact that Sb5+ is partially reduced by excess electrons in heavily doped β specimens at low oxygen pressures is explained.