Method for Calculating Ionic and Electronic Defect Concentrations in Proton Containing Perovskites

✍ Scribed by Finn Willy Poulsen

• Publisher: Elsevier Science
• Year: 1999
• Tongue: English
• Weight: 166 KB
• Volume: 143
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1006/jssc.1998.8092

✦ Synopsis

A general numerical method for calculation of concentrations of vacancies and ionic and electronic defects in solids in equilibrium with two gas pressures is presented. The method is applied to 5 at% B-site doped SrCeO 3 in equilibrium with oxygen and water vapor. The model includes protons and electronic defects, as well as cation vacancies on the A and B sites. The 10 concentrations in the model are determined uniquely by solving the linear and mass action law type equations in a rational sequence. No approximations or truncations of the equations are necessary. No information on the magnitude of the Schottky-equilibrium constant, K s , controlling the population of cation vacancies is available. Limiting values of K s were tested to illustrate suppression and enhancement of cation vacancy formation in perovskites. Deviations from Sieverts law are demonstrated. Deviation of the A/B ratio from unity has the same effect on the proton content as an increase of the dopant level.