Distribution of Σ3 misorientations in polycrystalline strontium titanate

SrTiO3 is a potential electrolyte material for solid-oxide fuel cells due to its high ion conductivity. Grain boundaries (GBs) play an important role in bulk ion conductivity. It has been reported that the resistance of Σ3 GBs is much lower than the general GB in SrTiO3. In order to clarify the conflicting reports on the prevalence of Σ3 GBs in SrTiO3, grain size and GB misorientations in Nb-doped and undoped SrTiO3 have been investigated as a function of annealing time. The observations suggest that the prevalence of both low-angle GBs and Σ3 GBs is strongly correlated to both abnormal grain growth and annealing time. In particular, the Σ3 GB population approaches that predicted by the Mackenzie random distribution when abnormal grain growth dominates.