Ni/NiO-carbon composite fibers prepared by solution blow spinning: Structure and magnetic properties

Abstract

Nickel/nickel oxide-carbon magnetic fibers were prepared by Solution Blow Spinning (SBS) of polyvinyl alcohol (PVA) and Ni-nitrate. As-spun fibers with relative Ni nitrate/PVA concentrations of 30 wt% and 60 wt% were calcined at 550 °C in argon flux. The samples characterization was carried out by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier-transform infrared (FTIR) spectroscopy, and DC magnetic measurements. TEM images show a carbon matrix containing sphere-like nanoparticles with diameters in the range of 4–45 nm. The magnetic assessment shows the presence of superparamagnetic small particles with blocking temperatures between 14 and 22 K, and large particles that are thermally blocked at 300 K. The low magnetization signal, with saturation magnetization in the range of 7–10 emu/g, is due to dead magnetic layers at the surface of nanoparticles.