Porous and superparamagnetic magnesium ferrite film fabricated via a precursor route

Porous magnesium ferrite film was fabricated via a single-source precursor strategy involving thermal conversion of (MgFe(III))-Fe-(II)-layered double hydroxide (MgFe-LDH) precursor film formed in situ on sulfonated silicon substrate, followed by selective etching of excessive MgO phase in the calcined precursor film. XRD and EDS analyses confirm the formation of single phase MgFe2O4 after etching of MgO. The as-formed MgFe2O4 film exhibits porous and particulate structure consisting of fused particle aggregates. AFM observation reveals the rough surface nature of the ferrite film. The magnetic characterization shows the enhanced saturation magnetization of MgFe2O4 film (ca. 37.1 emu/g), compared to that of MgFe2O4 powder synthesized by a conventional solid-state reaction. Importantly, the temperature-dependent magnetization of MgFe2O4 film exhibits unusual superparamagnetic characteristic. In addition, the film modified with organic molecule shows superhydrophobicity. Such significant magnetic and interfacial property of ferrite film can open up new opportunities for advanced applications of this material. (C) 2010 Elsevier B.V. All rights reserved.