title: Bicrystalline hematite nanowires.
abstract: Bicrystalline nanowires of hematite (alpha-Fe(2)O(3)) have been successfully synthesized by the oxidation of pure iron. The product was characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy (TEM), high-resolution TEM in combination with focal series reconstruction, energy-dispersive X-ray spectroscopy, and electron energy-loss spectroscopy. The bicrystalline nanowires have diameters of 20-80 nm and lengths up to 20 microm. All of the investigated materials are found to be alpha-Fe(2)O(3) with a rhombohedral crystal structure. Investigations indicate that most of the bicrystalline nanowires are nanotwins with ellipsoidal heads. The orientation relationship between the nanotwins can be described as (110)(M)//(110)(T), [110](M)//[0](T). An energy-filtered TEM investigation indicates that the ellipsoidal head is iron-rich. The growth mechanism of such unique nanostructures is considered to be a solid-phase growth via surface and internal diffusions of molecules from base to tip.
authors.affiliation: State Key Laboratory for Mesoscopic Physics, Department of Physics, Peking University, Beijing 100871, People's Republic of China. rmwang@pku.edu.cn
authors.forename: Rongming
authors.initials: R
authors.lastname: Wang
authors.forename: Yaofeng
authors.initials: Y
authors.lastname: Chen
authors.forename: Yunyi
authors.initials: Y
authors.lastname: Fu
authors.forename: Han
authors.initials: H
authors.lastname: Zhang
authors.forename: Christian
authors.initials: C
authors.lastname: Kisielowski