Grain boundaries in complex oxides. Technical progress report

Abstract

A quantitative comparison was achieved between space charge theory and segregation at grain boundaries in the model system TiO{sub 2}. The ionic space charge can be titrated from negative to positive potential. A space charge model was developed that includes the lattice defect chemistry. Defect formation energies in the Frenkel pair for TiO{sub 2} were studied. Grain boundary enthalpy was measured during coarsening. It was shown that it is the barium vacancy that forms near surfaces in donor-doped BaTiO{sub 3} electroceramics during oxidative-cooling.