Interfacial stability of ultrathin films of magnetite Fe3O4 (111) on Al2O3(001) grown by ozone-assisted molecular-beam epitaxy

Abstract

The thin films of iron oxides including magnetite (Fe3O4) and hematite (alpha-Fe2O3) have many important applications. Both forms of oxide can occur naturally during film growth by iron deposition under various oxidation environments; an important issue is to understand and control the process resulting in a single-phase film. We have performed the in-situ -time studies using X-ray diffraction of such film growth on sapphire (001) under pure ozone by monitoring the (00L) rod. Stable magnetite growth can be maintained at growth temperatures below 600 degrees C up to a certain critical film thickness, beyond which the growth becomes hematite. The results demonstrate the importance of interfacial interaction in stabilizing the magnetite phase. Published by AIP Publishing.