Controllable synthesis and magnetic properties of NiAl0.8Fe1.2O4 electrospun nanofibres

A convenient strategy for fabricating spinel ferrite NiAl0.8Fe1.2O4 (NAFO) nanofibres with a controllable draw ratio by an electrospinning technique was investigated. The surface topography and draw ratio of the NAFO nanofibres can be tuned by adjusting the molarity and polymer concentration of the precursors, calcination temperature and spinning voltage. Investigation of the magnetic performances showed that the saturation magnetization of NAFO nanofibres increased with increasing calcination temperature. This was interpreted by considering the cationic redistribution in the oxygen octahedral and oxygen tetrahedral sites of the mixed spinel ferrite as confirmed by X-ray diffraction, Raman spectra and X-ray photoelectron spectroscopy analysis. As the calcination temperature increased, the ferric ions showed a tendency to shift to the oxygen octahedral sites, while the divalent nickel ions showed a tendency to shift to the oxygen tetrahedral sites, which then strengthened the saturation magnetization of the NAFO nanofibres. The controllable synthesis strategy and the interpretation of the magnetic properties will shed some light on the application of one-dimensional NAFO nanofibres in spintronic and nanomagnetoelectric devices.