A space-charge model was applied to describe the equilibrium effects of segregation of double-donor oxygen vacancies to grain boundaries in dry and wet acceptor-doped samples of the perovskite oxide BaZrO3. The grain boundary (GB) core vacancy concentrations and electrostatic potential barriers resulting from different vacancy segregation energies were evaluated. Density-functional calculations on vacancy segregation to the mirror-symmetric Σ3 (112)[¯110] tilt grain boundary were also presented. The results indicated that oxygen vacancy segregation could be responsible for the low grain boundary proton conductivity in BaZrO3 reported in the literature.

Oxygen Vacancy Segregation and Space-Charge Effects in Grain Boundaries of Dry and Hydrated BaZrO3. B.J.Nyman, E.E.Helgee, G.Wahnström: Applied Physics Letters, 2012, 100[6], 061903