Oxygen ion conductivity of La0.8Sr0.2Ga0.83Mg0.17−xCoxO3−δ synthesized by laser rapid solidification

Materials La0.8Sr0.2Ga0.83Mg0.17−xCoxO3−δ with x = 0, 0.05, 0.085, 0.10, and 0.15 are synthesized by laser rapid solidification. It is shown that the samples prepared by laser rapid solidification give rise to unique spear-like or leaf-like microstructures which are orderly arranged and densely packed. Their electrical properties each show a general dependence of the Co content and the total conductivities of La0.8Sr0.2Ga0.83Mg0.085Co0.085O3−δ prepared by laser rapid solidification are measured to be 0.067, 0.124, and 0.202 S·cm−1 at 600, 700, and 800 °C, respectively, which are much higher than by conventional solid state reactions. Moreover, the electrical conductivities each as a function of the oxygen partial pressure are also measured. It is shown that the samples with the Co content values ≤ 8.5 mol% each exhibit basically ionic conduction while those for Co content values ≥ 10 mol % each show ionic mixed electronic conduction under oxygen partial pressures from 10−16 atm (1 atm = 1.01325 × 105 Pa) to 0.98 atm. The improved ionic conductivity of La0.8Sr0.2Ga0.83Mg0.085Co0.085O3−δ prepared by laser rapid solidification compared with by solid state reactions is attributed to the unique microstructure of the sample generated during laser rapid solidification. (condensed matter: electronic structure, electrical, magnetic, and optical properties)