Fabrication and magnetic properties of electrospun Ni1−xCuxFe2O4 nanofibers

• Ni1−xCuxFe2O4 nanofibers were prepared by electrospinning method.
• Ni1−xCuxFe2O4 have a single-phase cubic spinel structure.
• The lattice constant and crystallite size are increased with increasing Cu content.
• Cu2+ ion can substitute at both octahedral and tetrahedral sites of inverse spinel.
• Ni1−xCuxFe2O4 exhibits soft ferromagnetic.

Nickel copper ferrite Ni1−xCuxFe2O4 (x = 0.0, 0.1, 0.2, 0.3, 0.4, 0.5) nanofibers were successfully fabricated by electrospinning technique. The obtained nanofibers were calcined at a temperature of 600 °C, with a heating and cooling rate of 1 °C/min for 3 h. Samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), X-ray absorption near edge structure (XANES) and vibrating sample magnetometer (VSM). The diameters of the as-spun nanofibers as shown by SEM images are in the range of 360.95 ± 20–511.79 ± 25 nm and reduced to 73.60 ± 15–87.52 ± 18 nm after calcination. All calcined samples have a spinel ferrite structure as revealed by XRD and TEM. Crystallite size were calculated from the XRD peaks using Scherrer’s equation and found to increase from 18.46 to 30.78 nm with increasing Cu content. XANES results confirm the substitution of Cu cations on both of the octahedral and tetrahedral sites. The magnetization measurements reveal that the Ni1−xCuxFe2O4 nanofibers exhibit soft ferromagnetic behavior with decreasing magnetization from 37.71 to 15.10 emu/g and increasing coercivity from 50.90 to 144.66 Oe as the Cu content is increased.

This figure shows the good fitting of the simulation and experimental Cu K-edge XANES spectra of Ni1−xCuxFe2O4 nanoparticles indicating the substitution of Cu2+ ion in the tetrahedral and octahedral sites of Ni1−xCuxFe2O4 spinel structure, which can result in the decrease of the magnetization.Figure optionsDownload as PowerPoint slide