Transport properties of multi-cations doped cerium oxide

The transport properties of members of the solid solution (100 - x)CeO ₂·xLa_0.6Sr_0.4CoO₃ (CexLSC), where x = 5, 7.6, and 10.6 mol% have been investigated under oxidising and mildly reduce atmospheres. The single phase solid solutions CexLSC have fluorite-type structure (space group Fm3̄m) with Ce replaced by La, Sr, and Co. The unit cell volume expands with increasing degree of substitution. The CexLSC compositions exhibit thermally activated conductivity behaviour over a temperature range of 150-900 °C. The bulk conductivity increases up to 5-6 orders of magnitudes. In contrast to the undoped CeO₂, the grain boundary conductivity determines the transport properties of the CexLSC solid solutions only below 200 °C. The total conductivity of the CexLSC compositions with x > 5 mol% seems to be enhanced due to the increase in the concentration of oxygen vacancies and the emergence of the hole charge carriers. Results obtained in the present study demonstrate that the fabrication method does not greatly influence the transport properties of the CexLSC solid solutions.