The microstructures of sub-grain boundaries in as-annealed undoped single crystals were studied. When the crystal quality was good, it was difficult to observe lattice defects using only transmission electron microscopy, and supplementary observations made using X-ray topography were useful. The latter revealed the defect distribution throughout the crystal. It was found that [011]-type crystals usually exhibited sub-grain textures. High-resolution transmission electron microscopy showed that the sub-grain boundaries were small-angle tilt boundaries which were made up of partial dislocations having ½<110> Burgers vectors. There was no segregation of impurities.

High-Resolution Electron Microscopy of a Subgrain Boundary in Strontium Titanate Single Crystals. J.Yamanaka: Materials Transactions, 2001, 42[6], 1131-34