Electrical conductivity of the al-stabilized La2/3TiO3

A-site deficient lanthanum titanate (La(2/3)TiO(3)) materials with perovskite structure are attractive due to their electrical applications such as ion conductors and dielectrics. However, its stability at room temperature in air is obtained only if Na or Li etc. is incorporated into La site or Al into Ti site. In this study, the electrical conductivities of La(0.683)(Ti(0.95)Al(0.05))O(3) have been measured in oxygen partial pressure (Po(2)) between 1 and 10(-18) atm at 1000 similar to 1400 degrees C. The electrical conductivity exhibited -1/4, -1/6 and -1/5 dependence (log sigma proportional to log P(o2)(n), n=-1/4, -1/6, -1/5) depending upon temperature and Po(2). The defect model explaining the observation was proposed and discussed. The chemical diffusion coefficient was estimated from the electrical conductivity relaxation.