Electrical conductivity of Sr and Mg doped LaAlO3

The electrical conductivity of 10% Sr and 10% Mg doped LaAlO3 (LSAM9191) was measured using impedance spectroscopy at temperatures between 400 and 1000 °C. Between 800 and 1000 °C, the conductivity was also measured as a function of oxygen partial pressure (PO2). Below 550 °C, the grain boundary resistance mostly determined the overall conductivity that nearly disappeared above 800 °C. In the temperature region where the sample resistance is mostly determined by grain property, LSAM9191 was an oxygen ion conductor at low PO2 and a mixed conductor at high PO2. With increasing temperature, the ionic conduction region only slightly increased. Thus, LSAM9191 is a promising material as an oxygen ion conductor at high temperature in low PO2.