High temperature electrical conductivity of epitaxial Gd-doped CeO2 thin films

Single-crystalline epitaxial Gd-doped CeO2 (GCO, Gd0.2Ce0.8O1.9 ) thin films were grown on (001) NdGaO3 (NGO) and LaAlO3 (LAO) substrates through pulsed-laser deposition. The electrical conductivity was investigated by AC impedance spectroscopy. The temperature dependence of the electrical conductivity gives an activation energy of 0.74 eV for GCO/NGO and a conductivity which is very close to that of the bulk polycrystalline material. For GCO films deposited on LAO, the conductivity of the substrate makes a significant contribution to the total measured conductivity.