LAUSR

The misfit dislocations at α‐Fe2O3/α‐Al2O3 heterostructure interfaces were investigated by high‐resolution transmission electron microscopy (HRTEM), geometric phase analysis (GPA) and dislocation density tensor analysis. When imaged along the [11 2¯ 0] direction, the misfit dislocation core is a mixed‐type, which can be characterised by one extra (1 1¯ 02) plane and one extra ( 1¯ 104) plane of α‐Al2O3. Dislocation density tensor analysis gave a very high accuracy in determining the corresponding Burgers vectors of two extra half‐planes. By comparing the measured Burgers vectors with theoretical ones, we are able to determine local rotations in the dislocation core region: the (1 1¯ 02) plane is rotated clockwise 6.25° and the ( 1¯ 104) plane is rotated anticlockwise 4.81°. Such a local rotation is favourable from the viewpoint of both energy and function to relax lattice misfit.