Magnetic Behavior of Iron Oxide Thin Films for Biomedical Applications

Iron oxide has found wide applications in biomedical including targeted drug delivery, magnetic hyperthermia etc. For the use of iron oxide in biomedical application we here report the preparation of iron oxide thin films using spin coating technique. Films are prepared with variation in Fe2+/Fe3+ ratio as 0.5, 0.75 and 1. Films prepared with Fe3+ cations alone are also studied. Films are characterized under as-deposited conditions. Presence of diffraction peaks corresponding to (311), (220) and (400) planes indicate the formation of pure magnetite phase with Fe2+/Fe3+ ratio as 0.5. With increase in Fe2+/Fe3+ ratio to 1 the phase transition from magnetite to maghemite phase is observed. These films show superparamagnetic behavior making them ideal candidate for biomedical applications. The phase transition in magnetic films from magnetite to maghemite is accompanied by decrease in saturation magnetization. Films with Fe3+ cations alone show maghemite and hematite mixed phases that results in weak ferromagnetic behavior.