Study of the Properties of Iron Oxide Nanostructures

Iron oxides exist in a rich variety of structures and occur in a great variety of settings, from geological to nanoscale technological applications. Ferrous and ferric iron oxides present seven crystalline phases, the more common are α-Fe2O3 (hematite), γ-Fe2O3 (maghemite), Fe3O4 (magnetite) and Fe1-xO (wustite); the less commonly found are the βand ε-Fe2O3 phases and the low-temperature rhombohedrical structure of magnetite. Thanks to their fascinating properties, all of these oxides have been widely investigated by chemists, engineers, and physicists. These phases have been used successfully in many applications; e.g., magnetite nanoparticles have been used in cancer diagnosis and therapy [1], drug delivery vehicles [2], and in water remediation [3]. Magnetite thin films lend themselves to room temperature applications in the construction of different devices such as tunneling magnetoresistance, giant magnetoresistance and magnetic random-access memory devices [4]. Maghemite is used in magnetic resonance imaging [5], magnetic recording media [6], fabrication of biocompatible magnetic fluids [7], and electrochromic devices [8]. Hematite nanostructures have been explored in the development of electrochromic devices [8], as cathodes in lithium batteries [9], and in the construction of photoelectrochemical systems to produce hydrogen from water using solar radiation [10]. Thin films of wustite/maghemite have been used in solar radiation filters [11].