A [001](110) small-angle grain boundary was studied using electron energy-loss spectroscopy and high-resolution transmission electron microscopy. The a[110] grain boundary dislocations were dissociated into two partial dislocations involving climb of the partials. From their separation, an upper limit on the (110) antiphase boundary energy (720mJ/m2) was deduced. Electron energy-loss spectra were obtained from the partial cores and the antiphase boundary using a dedicated scanning transmission electron microscope. The Sr/Ti ratio was found to be increased in one of the partial cores but decreased in the other. This could be understood from the dissociation mechanism. From the increase of the Ti/O ratio, it was concluded that the dislocation cores were oxygen-deficient. Electron energy-loss spectra indicated a reduction of Ti in the partial dislocation cores as well as a reduced crystal field.

Electronic and Atomic Structure of a Dissociated Dislocation in SrTiO3. Z.Zhang, W.Sigle, W.Kurtz, M.Rühle: Physical Review B, 2002, 66[21], 214112