| Abstract
| - By carefully controlling the reacting conditions, including atmosphere, temperature, and time, we directlyacquire the nanowires of γ-Fe2O3 from the nanowires of α-Fe2O3 in a reduced atmosphere. X-ray diffraction,X-ray photoelectron spectroscopy, Raman spectrum, and transmission electronic microscope analysesdemonstrate that the nanowires are single-crystalline γ-Fe2O3. The nanowires have a diameter ranging from50 to 90 nm and their typical lengths are in the range of 10∼20 μm. The optical property of the nanowiresis observed by photoluminescence spectrum. The magnetic behavior of it is investigated by a magnetic propertymeasurement system. The blocking temperature is found to be about 200 K. In addition, the mechanism ofthe transformation from α-Fe2O3 nanowires to γ-Fe2O3 nanowires is preliminarily studied by ab initio approach.It is found that the role of H2 is to change the Fe−O bonds in α-Fe2O3 nanowires, and then α-Fe2O3 istransformed into γ-Fe2O3.
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