Surface morphology, optical band gap and magnetic behavior of Cu(1-x)MnxFe2O4 nanofibers prepared by sol-gel electrospinning

Abstract

Novel manganese-substituted copper ferrite (Cu(1−x)MnxFe2O4; x = 0, 0.25, 0.5, and 0.75) nanofibers has been prepared via sol-gel electrospinning technique. The structural, chemical, morphological, elemental, optical and magnetic characteristics of the fibers were investigated. XRD analysis revealed that tetragonal phase of ferrites with impurity phases (CuO, α-Fe2O3 and α-MnO2) was formed. The Williamson–Hall approach indicated that the average crystallite size and lattice strain of the samples were changed by Mn incorporation and then FTIR spectroscopy confirms the characteristic vibration modes of ferrites atoms at tetrahedral and octahedral sites. Field emission scanning electron microscopy (FESEM) emphasized that Cu(1−x)MnxFe2O4 nanofibers were fabricated with some special morphologies after Mn ions incorporation, nanowebs (x = 0.25), beaded nanofibers (x = 0.5), and coarse nanofibers (x = 0.75) with average diameters in the range of 63–93 nm. EDS spectroscopy confirmed the presence of Fe, O, Cu and Mn elements and indicated that the atomic ratio of the elements was close to the nominal values in the initial sols. It was found that the optical band gap of Cu(1−x)MnxFe2O4 changes by Mn incorporation, ranging from 1.5 to 1.8 eV. VSM analysis at room temperature showed normal ferromagnetic behavior of ferrites but a large coercivity (3.11 kOe) is observed for Cu0.25Mn0.75Fe2O4 nanofibers. The saturation magnetization enhanced by Mn incorporation up to x = 0.5 (Ms = 28.7 emu/g).