V. Ravikumar et Vp. Dravid, ATOMIC-STRUCTURE OF UNDOPED SIGMA=5 SYMMETRICAL TILT GRAIN-BOUNDARY IN STRONTIUM-TITANATE, Ultramicroscopy, 52(3-4), 1993, pp. 557-563
The atomic structure of a pristine Sigma = 5 grain boundary in SrTiO3
has been investigated using a variety of transmission electron microsc
opy (TEM) techniques. No cation non-stoichiometry or impurity segregan
ts could be detected at the boundary within the limits of the energy d
ispersive X-ray microanalysis technique used, while preliminary electr
on energy loss spectroscopy analysis reflects that changes in the opti
cal/dielectric function or the valence of the cations at the interface
are too subtle to be detected with our coarse scale measurements. Hig
h-resolution transmission electron microscopy indicates a symmetrical
tilt grain boundary with a (130)-type grain boundary plane. The grain
boundary has a compact core, with negligible plane-normal rigid body t
ranslation (RBT). An in-plane RBT of 1/2d(130) (similar to 0.62 Angstr
om) is identified from the high-resolution electron micrographs. A sem
i-empirical model of the relaxed atomic structure of the grain boundar
y based on crystal chemistry principles is proposed, which includes th
e observed RBT and individual atomic relaxations at the boundary core.