Synthesis and characterization of mixed conductor CeNbO4

CeNbO4 samples were synthesized via solid state reactions and characterized by XRD, XPS, internal friction and impedance measurements. The XRD pattern showed that the sample quenched from 1173 K to room temperature was mainly composed of monoclinic CeNbO4 phase. XPS analysis showed that the oxygen lattice can be present in form of Ce-O and Nb-O while niobium exists in Nb5+ state and cerium exists in both Ce3+ and Ce4+ states. One relaxation process was observed by the internal friction (IF) measurement, which was attributed to the short distance migration of interstitial oxygens. The activation energy of the IF peak is deduced to be 0.34 eV. In the impedance measurement, the ionic transfer number estimated by impedance calculation was about 0.4. The activation energies for ionic conductivity (Eion), electronic conductivity (Ehole) and total conductivity (Et) were calculated to be 0.34, 0.29, and 0.64 eV, respectively.