Preparation and magnetic properties of ZnFe2O4 nanofibers by coprecipitation–air oxidation method

ZnFe2O4 nanofibers have been reproducibly synthesized by the thermal treatment of the fiber-like precursor that was fabricated by the oxidation of a coprecipitation product obtained by Zn2+ and Fe2+ in a NaOH solution. The phase, morphology, and particle diameter were examined by X-ray diffraction (XRD) and transmission electron microscopy (TEM), respectively. The magnetic properties of the samples were studied using a vibrating sample magnetometer (VSM). It indicated that the diameters of obtained ZnFe2O4 nanofibers were found to range between 10 and 15 nm; the length ranged between 2 and 3 μm. With the increase in the calcination temperature, the length of ZnFe2O4 nanofibers reduced and the diameter increased appreciably; the coercivity of the ZnFe2O4 samples reduced and the saturation magnetization increased. When the calcination temperature was 600 °C, the coercivity, saturation magnetization and remanent magnetization of the samples were 93.1 Oe, 23.5 emu g−1 and 4.3 emu g−1, respectively, evidently far higher than those of the spherical ZnFe2O4.