Electron microscopic study of twins, anti - phase boundaries, and dislocations in thin films of rutile

The defect structure of the rutile modification of TiOj is studied by means of electron microscopy and electron diffraction. Two new methods are described for the preparation of thin films of rutile. Geometrically shaped contrast features are often observed in these films and can be ascribed to plate-like cavities.
Extended fringe patterns, which sometimes form closed loops are attributed to antiphase boundaries. A model for the occurence of this type of defects is proposed, based on the idealized image of a hexagonal close packed stacking of the oxygen ions in the rutile structure. All the observations, such as: motion, disappearance of closed loops under heating, interaction with dislocations and the habit plane of the anti-phase boundaries are reliable with the proposed model. The presence of twins with (101) boundary plane is explained on the same basis.