Structural and magnetic properties of Ni/C core–shell nanofibers prepared by one step co-axial electrospinning method

Nickel/carbon (Ni/C) nanofibrous structures with magnetic material nickel in the core and carbon in the shell are fabricated by the co-axial electrospinning method. The crystallinity, morphology, elemental composition, and microstructure of the carbonized nanofibers are characterized by X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), energy-dispersive X-ray spectroscopy (EDX), and high-resolution transmission electron microscope (HRTEM) respectively. Rietveld refinement method of XRD pattern was carried out to determine the structural parameters of face-centered cubic (FCC) Ni with space group Fm3m . The average crystallite size and the lattice strain have been calculated using the Williamson–Hall (W–H) plot method. It is demonstrated that the compressive lattice strain is attributed due to the presence of polymer-derived carbon material. Raman data confirms the formation of pure C in the Ni/C nanofibers. Furthermore, a vibrating sample magnetometer (VSM) is used for the magnetic measurement of the Ni/C nanofibers. It is observed that the nanofibers show typical ferromagnetic behavior having the optimum value of saturation magnetization of 5.12 emu/g. The temperature-dependent magnetic measurements suggest the ferromagnetic behavior of Ni/C nanofibers within the room temperature (300 K).