One-dimensional NiCuZn ferrite nanostructures: Fabrication, structure, and magnetic properties

Ni0.5−xCuxZn0.5Fe2O4 (0.0≤x≤0.5) ferrite nanofibers with diameters of 80–160 nm have been prepared by electrospinning and subsequent heat treatment. Both the average grain size and lattice parameter are found to increase with the addition of copper. Fourier transform infrared spectra indicate that the portion of Fe3+ ions at the tetrahedral sites move to the octahedral sites as some of the substituted Cu2+ ions get into the tetrahedral sites. Vibrating sample magnetometer measurements show that the coercivity of these ferrite nanofibers decreases with increasing Cu concentration, whereas the specific saturation magnetization initially increases, reaches a maximum value at x=0.2 and then decreases with the Cu content further increase. Notable differences in magnetic properties at room temperature (298 K) and 77 K for the Ni0.3Cu0.2Zn0.5Fe2O4 nanofibers and corresponding powders are observed and mainly arise from the grain size and morphological variations between these two materials.