Structure of the Fe<inf>2</inf>O<inf>3</inf>-Al<inf>2</inf>O<inf>3</inf> (1(formula presented)02) interface

The interface structure of α-Fe2O3 islands grown directly on an electron transparent Al2O3 (1(formula presented)02) substrate by low-pressure chemical vapour deposition has been characterized by weak-beam imaging in the transmission electron microscope. The islands exhibited irregular moiré patterns, suggesting that tilting of the Fe2O3 occurs as a means of partially accommodating the 5·5% lattice misfit at the interface. Consistent with this observation, numerous types of misfit dislocation network were observed. One type of network was identified as an othogonal array of b=⅓ ⟨11(formula presented)0⟩ and b=⅓⟨(formula presented)101⟩ perfect edge dislocations. A second type of network is most probably an array of perfect dislocations with Burgers vectors inclined to the interface which has been directly associated with tilting of the Fe2O3 island. The observation suggests that the introduction of misfit dislocations at the (1(formula presented)02) interface is more difficult than at the (0001) interface. © 1993 Taylor & Francis Group, LLC.