Strain relaxation studies of the Fe3O4/MgO(100) heteroepitaxial system grown by magnetron sputtering

Detailed strain relaxation studies of epitaxial magnetite, Be3O4, films on MgO(100) substrates grown by magnetron sputtering reveal the accommodation of strain up to 600 nm thickness, a thickness far above the critical thickness (t(C)) predicted by theoretical models. The results are in agreement with the suggestion that the excess strain in Fe3O4/MgO(100) heteroepitaxy is accommodated by the presence of antiphase boundaries. The compressive strain generated by the antiphase boundaries compensates for the tensile strain within the growth islands, allowing the film to remain fully coherent with the substrate. Contrary to earlier findings, magnetization decreases with an increase in the film thickness. This vindicates the view that the structure of the antiphase boundaries depends on the growth conditions.