Chemical bonding at the boundary of a bi-crystal of Fe3+-doped material was studied by using spatially-resolved electron energy-loss spectroscopy and first-principles molecular orbital calculations. The near-edge structure of the O K-edge spectrum on the boundary showed that the nature of the TiO6 linkage was different to that in the bulk. The linkage changed locally from a corner-sharing configuration to an edge-sharing configuration at the same time that Sr2+ ions were removed from the boundary. It was concluded that this type of theoretical calculation was a powerful aid to the analysis of electron energy-loss spectra in the absence of a preconceived model.

I.Tanaka, T.Nakajima, J.Kawai, H.Adachi, H.Gu, M.Rühle: Philosophical Magazine Letters, 1997, 75[1], 21-7