Growth and properties of single-crystalline γ-FeO nanowires

By carefully controlling the reacting conditions, including atmosphere, temperature, and time, we directly acquire the nanowires of γ-Fe O from the nanowires of α-FeO in a reduced atmosphere. X-ray diffraction, X-ray photoelectron spectroscopy, Raman spectrum, and transmission electronic microscope analyses demonstrate that the nanowires are single-crystalline γ-Fe O. The nanowires have a diameter ranging from 50 to 90 nm and their typical lengths are in the range of 10-20 μm. The optical property of the nanowires is observed by photoluminescence spectrum. The magnetic behavior of it is investigated by a magnetic property measurement system. The blocking temperature is found to be about 200 K. In addition, the mechanism of the transformation from α-FeO nanowires to γ-FeO nanowires is preliminarily studied by ab initio approach. It is found that the role of H is to change the Fe-O bonds in α-FeO nanowires, and then α-FeO is transformed into γ-Fe O. © 2007 American Chemical Society.