Temperature-dependent Raman study of Ce_(0.75)Nd_(0.25)O_(2-δ) nanocrystals

摘要

Raman spectra of Nd doped ceria nanocrystals were measured by gradual heating and cooling over the temperature range of 293-1073 K and analyzed using the phonon confinement model that incorporates inhomogeneous strain and anharmonic effects. We have demonstrated that in nanograins, four-phonon anharmonic processes are more dominant at higher temperatures than size effects. After the heat treatment, Nd doped ceria nanocrystals remain of nanometric range (～20 nm) while the concentration of oxygen vacancies is still high in ceria lattice, making this material convenient for solid oxide fuel cells application.