Abstract NiZn ferrite/polyvinylpyrrolidone composite fibres were prepared by sol--gel assisted electrospinning. Ni0.5Zn0.5Fe2O4 nanofibres with a pure cubic spinel structure were obtained subsequently by calcination of the composite fibres at high temperatures. This paper investigates the thermal decomposition process, structures and morphologies of the electrospun composite fibres and the calcined Ni0.5Zn0.5Fe2O4 nanofibres at different temperatures by thermo-gravimetric and differential thermal analysis, x-ray diffraction, Fourier transform infrared spectroscopy and field emission scanning electron microscopy. The magnetic behaviour of the resultant nanofibres was studied by a vibrating sample magnetometer. It is found that the grain sizes of the nanofibres increase significantly and the nanofibre morphology gradually transforms from a porous structure to a necklace-like nanostructure with the increase of calcination temperature. The Ni0.5Zn0.5Fe2O4 nanofibres obtained at 1000 ℃ for 2 h are characterized by a necklace-like morphology and diameters of 100--200 nm. The saturation magnetization of the random Ni0.5Zn0.5Fe2O4 nanofibres increases from 46.5 to 90.2 emu/g when the calcination temperature increases from 450 to 1000 ℃. The coercivity reaches a maximum value of 11.0 kA/m at a calcination temperature of 600 ℃. Due to the shape anisotropy, the aligned Ni0.5Zn0.5Fe2O4 nanofibres exhibit an obvious magnetic anisotropy and the ease magnetizing direction is parallel to the nanofibre axis.
Received: 30 November 2008
Revised: 05 March 2009
Accepted manuscript online:
PACS:
81.16.-c
(Methods of micro- and nanofabrication and processing)
Fund: Project supported by the National
Natural Science Foundation of China (Grant No 50674048) and the
Aerospace Science Foundation of China (Grant No 2007ZF52062).
Cite this article:
Xiang Jun(向军), Shen Xiang-Qian(沈湘黔), Song Fu-Zhan(宋福展), and Liu Ming-Quan(刘明权) Fabrication and magnetic properties of Ni0.50.5Zn0.5Fe2O4 nanofibres by electrospinning 2009 Chin. Phys. B 18 4960
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