Highly ordered CoFe₂O₄ nanowires array prepared via a modified sol-gel templated approach and its optical and magnetic properties

Highly ordered one-dimensional CoFe₂O₄ nanowires array possesses unique properties due to the lowdimensional effect, which make it a wide range of potential applications. In this paper, ordered CoFe ₂O₄ nanowires array was prepared by a modified sol-gel method using anodic aluminum oxide template. Microstructure analysis performed by X-ray diffraction, scanning electron microscope, transmission electron microscope, and Raman spectra indicated the crystallization of pure CoFe ₂O₄ phase. The nanowires were constituted by polycrystalline CoFe₂O₄ nanograins with an average size of 15 nm, which results in an increase of band gap as evidenced by photoluminescence spectra. Furthermore, we found that the CoFe₂O ₄ nanowires were coated with amorphousAl₂O₃ forming a core-shell structure. The formation mechanism of this structure was discussed. The nanowires array preserved the good magnetic property of CoFe ₂O₄ bulk material, showing the prospect for applications.