Effect of MnO2 concentration on the conductivity of Ce0.9Gd0.1MnxO2-δ

Abstract

Samples with the composition Ce0.9Gd0.1MnxO2-δ with x = 0.01, 0.02, and 0.05 Mn-addition were prepared by mixed oxide route from Ce0.9Gd0.1O2-δ and MnO2 and sintered at 1300 °C. The electronic conductivity was measured using a modified Hebb-Wagner technique, the electrical conductivity was investigated by impedance spectroscopy, and oxygen permeation was measured for the sample with x = 0.05. An increase of the electronic partial conductivity with increasing Mn addition was observed, which can be attributed to an additional Mn 3d-related state between the top of the valence band and the bottom of the Ce 4f band. The grain boundary conductivity was found to be suppressed for low Mn contents, but enhanced for the sample with x = 0.05.