Strain relaxation studies in epitaxial magnetite, Fe3O4, thin films grown onto

MgAl2O4(100) substrates were reported. The study showed that the films were

relaxed; in accord with the theoretical prediction for a critical thickness of 5nm.

Antiphase boundaries were not expected to form in Fe3O4 films grown onto

MgAl2O4 substrates, because both film and substrate had the same crystal

symmetry. On the other hand, the present study revealed the formation of antiphase

boundaries within the Fe3O4 films. The analysis showed that the antiphase

boundaries in a Fe3O4/MgAl2O4 hetero-epitaxial system were formed from partial

dislocations, which accommodated the misfit. This formation mechanism for

antiphase boundaries was fundamentally different to that found in the Fe3O4/MgO

system; where antiphase boundaries were formed as a consequence of equivalent

nucleation sites on the MgO substrate separated by non-translational vectors of the

Fe3O4 lattice. The mechanism for the formation of antiphase boundaries through

partial dislocations was expected to be applicable to a wide range of epitaxial

systems having identical symmetries of the film and the substrate and a significant

lattice mismatch.

Strain Relaxation in Fe3O4/MgAl2O4 Heterostructures: Mechanism for Formation

of Antiphase Boundaries in an Epitaxial System with Identical Symmetries of Film

and Substrate. M.Luysberg, R.G.S.Sofin, S.K.Arora, I.V.Shvets Physical Review

B, 2009, 80[2], 024111