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 low-dimensional effect, which make it a wide range of potential applications. In this paper, ordered CoFe2O4 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 CoFe2O4 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 CoFe2O4 nanowires were coated with amorphous Al2O3 forming a core–shell structure. The formation mechanism of this structure was discussed. The nanowires array preserved the good magnetic property of CoFe2O4 bulk material, showing the prospect for applications.

► Ordered CoFe2O4 nanowires array was prepared by a modified sol–gel template method.
► The nanowires are composed of nanosized CoFe2O4 grains with around 15 nm.
► CoFe2O4 nanowires are coated with amorphous Al2O3 forming core–shell structure.
► The optical band gap of CoFe2O4 nanowires increases.
► The nanowires array preserves the good magnetic property of CoFe2O4 bulk material.