Temperature dependence of faceting in Σ5(310)[001] grain boundary of SrTiO3 Original Research Article

Using high-resolution electron microscopy (HREM), temperature dependence of faceting of an asymmetric Σ5 grain boundary (GB) in SrTiO3 is observed. The bicrystal samples have been fabricated by ultra-high vacuum diffusion bonding and heat-treated between 1100 and 1600 °C. Below 1300 °C, this GB facets into symmetric (310) and asymmetric (100)//(430) GB planes. At 1300 °C, in addition to the asymmetric facet, the symmetric {210} facet appears: three different facets are thus observed at this temperature. At 1400 and 1500 °C, the asymmetric facet disappears and the two kinds of symmetric facets remain. At 1600 °C, faceting disappears and the GB becomes defaceted. The faceting/defaceting transition behavior of the GB is interpreted in terms of the Wulff plot and its corresponding equilibrium crystal shape.