| Autor: |
De-Sheng, Xue, Li-Ying, Zhang, Cun-Xu, Gao, Xue-Fei, Xu, An-Biao, Gui |
| Zdroj: |
Chinese Physics Letters; April 2004, Vol. 21 Issue: 4 p733-736, 4p |
| Abstrakt: |
Quasi-one-dimensional Fe3O4 nanowires in diameter of about 200 nm were assembled into anodic aluminium oxide templates via electrodepositing and heat-treating processes. The nanowires have a polycrystalline spinel structure with a = 8.317 Å, and each nanowire is composed of fine Fe3O4 crystallites with size of about 30 nm. The magnetic moments of Fe3O4 crystallites in nanowires have a preferred orientation leaning to the wire axis but not parallel to the wire axis. Mössbauer spectra (MS) were used to verify the presence of Fe3O4 further and the existence of superparamagnetic particles in nanowires. A perpendicular magnetic anisotropy was observed obviously. Temperature dependence of the magnetic moments (MT) shows that the Verwey transition for the Fe3O4 nanowires occurs at 50 K, and the behaviour of the MT curve is different from that of other magnetite materials. These characteristic magnetic properties of Fe3O4 nanowires are mainly due to the reduced dimension and the configuration of preferred orientation in the nanowires caused by the shape anisotropy. |
| Databáze: |
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