Ionic Transport Properties in Nanocrystalline Ce(0.8)A(0.2)O(2-δ) (with A = Eu, Gd, Dy, and Ho) Materials

The ionic transport properties of nanocrystalline 20 mol% Eu, Gd, Dy, and Ho doped cerias, with average grain size of around 14 nm were studied by correlating electrical, dielectric properties, and various dynamic parameters. Gd-doped nanocrystalline ceria shows higher value of conductivity (i.e., 1.8 × 10(−4) S cm(−1) at 550°C) and a lower value of association energy of oxygen vacancies with trivalent dopants Gd(3+) (i.e., 0.1 eV), compared to others. Mainly the lattice parameters and dielectric constants (ε(∞)) are found to control the association energy of oxygen vacancies in these nanomaterials, which in turn resulted in the presence of grain and grain boundary conductivity in Gd- and Eu-doped cerias and only significant grain interior conductivity in Dy- and Ho-doped cerias.