Aligned Ferrite Nanofibers Fabricated by Electrospinning

Abstract

Using polyethylene pyrrole(PVP) and metal nitrate as precursors,smooth,uniform,and aligned Co0.8Zn0.2Fe2O4 nanofibers were prepared via electrospinning and sol-gel method,and subsequent heating process.The thermal decomposition process,crystal structure,and morphology of the nanofibers were studied by means of thermogravimetric-differential thermal analysis(TG-DTA),Fourier transform infrared spectroscopy(FTIR),X-ray diffraction(XRD),scanning electron microscopy(SEM),and transmission electron microscopy(TEM),respectively.Co0.8Zn0.2Fe2O4 nanofibers with particle sizes of 20.5—61.9 nm and a well-developed spinel structure were successfully obtained after calcinations of the as-spun nanofibers at 550—950 ℃ in air for 3 h.The as-spun nanofibers collected at 2000 r/min with the best morphology is ca.300 nm in diameter,which decreases down to ca.70 nm on annealing at 750 ℃ from SEM and TEM images.Room temperature magnetization results showed a ferromagnetic behavior of the calcined Co0.8Zn0.2Fe2O4 nanofibers.Compared with CoFe2O4 nanofibers,the anisotropy of Co0.8Zn0.2Fe2O4 nanofibers decreased,resulting in the lower coercivity(Hc) and higher saturation magnetization(Ms) of the obtained sample.The Ms of the sample increased with the calcinations temperature,while the Hc reaches a maximum value of 16.6 A/m at the calcinations temperature of 750 ℃.The Hc results suggest that the critical single-domain size of Co0.8Zn0.2Fe2O4 is about 44 nm.In comparison with a powder sample prepared using conventional sol-gel process,significant differences in magnetic properties were noted between these two samples.