Ionic and electronic conductivities of LaCoO3- and LaMnO3-based perovskite-type oxides measured by the a.c. impedance method with electron-blocking electrodes

The ionic conductivities, σi, of La0.6Sr0.4Co1–yNiyO3(y= 0, 0.02) have been measured by the a.c. four-probe method with electron-blocking electrodes, and compared with diffusivity of oxygen from the oxygen isotopic-exchange reaction. The ionic conductivities estimated from both methods are similar. σi; values for the perovskite-type oxides La0.6Sr0.4Co0.98Ni0.02O3 were higher than that of (ZrO2)0.92(Y2O3)0.08(YSZ), and the ionic transference numbers were in the range 1 × 10–4– 5 × 10–6 for 900–600 °C. La0.6Sr0.4MnO3 is considered to exhibit lower ionic conductivities than La0.6Sr0.4Co1–yNiyO3(y= 0, 0.02) and σi of this oxide could not be measured by the a.c. fourprobe method with electron-blocking electrodes.