J Mater Sci Technol ›› 2011, Vol. 27 ›› Issue (11): 985-990.

• Nanomaterials and Nanotechnology • Previous Articles     Next Articles

Thermal Growth and Nanomagnetism of the Quasi-one Dimensional Iron Oxide

Minglong Zhong, Zhongwu Liu, Xichun Zhong, Hongya Yu, Dechang Zeng   

  1. School of Materials Science and Engineering, South China University of Technology, Guangzhou 510640, China
  • Received:2011-03-10 Revised:2011-07-23 Online:2011-11-30 Published:2011-11-29
  • Contact: Zhongwu Liu
  • Supported by:

    the Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry of China, the Natural Science Foundation of
    China (Grant Nos. U0734001, 50874050), and the Fundamental Research Funds for the Central Universities, SCUT (Grant No. 2009ZZ0025)

Abstract: Quasi-one dimensional iron oxide nanowires with flat needle shape were synthesized on the iron powders by a rather simple catalyst-free thermal oxidation process in ambient atmosphere. The characterization by field emission scanning electron microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction  (XRD), Raman and high-resolution transmission electron microscopy (HRTEM) revealed that these nanostructures are single crystalline α-Fe2O3. The various dimensions with 40-170 nm in width and 1-8 μm in length were obtained by tuning the growth temperature from 280 to 480°C. A surface diffusion mechanism was proposed to account for the growth of quasi-one dimensional nanostructure. The typical α-Fe2O3 nanowires
synthesized at 430°C had a reduced Morin temperature TM of 131 K in comparison with their bulk counterpart. The coercivitis Hc of these nanowires are 321 and 65 Oe at 5 and 300 K, respectively. The temperature of synthesis also has important effects on the magnetic properties of these nanowires.

Key words: Thermal growth, One-dimensional nanostructures, Iron oxide, Magnetic materials