Fabrication And Investigation Of Magnetic Properties Of Nickel-zinc Ferrites Nano Magnetic Materials

Electrospinning was a method of preparation of untralong nanofiber, whith was regard as the simplest, versatile and general technique. It can be used to synthesis nanofibres, such as porous, nanotube, multichannel, core-shell and aligned. In the paper, using metal nitrate and polyethylene pyrrole (PVP) as precursors, Nio.5Zn0.5Fe204nanoparticles (NPs) has been successfully prepared via a traditional sol-gel process; smooth, well-aligned uniform and smooth surface Ni0.5Zn0.5Fe2O4nanofibres (NFs) and Ni0.5Zno.5Fe204/ZnO namofibers have been successfully prepared by electrospinning technique and coaxial electrospinning. Crystal structure and chemical component of those NPs and NFs were characterization by energy dispersive spectrometer (EDS) and X-ray diffraction (XRD), respectively. In order to optimize the parameters during the process, the morphology and structure of Ni0.5Zno.5Fe2O4and Nio.5Zno.5Fe2O4/ZnO NFs were observed using scanning electronic microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM). Room temperature magnetization of NPs and NFs were examined by vibrating sample magnetometer (VSM). We also discussed calcination temperature and chemical on the microstructure and magnetic properties of Ni0.5Zno.5Fe2O4(NPs) and Ni0.5Zno.5Fe2O4and Ni0.5Zno.5Fe2O4/ZnO NFs.Researches show that well-developed structures of Ni0.5Zno.5Fe2O4NPs and Nio.5Zno.5Fe2O4and Nio.5Zno.5Fe2O4/ZnO NFs were successfully obtained after annealing the as-spun nanofibres at650℃-850℃in air for3h. The diameter of the as-spun NFs were shrink sharply after calcination, and the morphology of NFs were change from rough, porous and finally necklace like structure during the calcination process. The lattice constant has increased due to thermal expansion and small grain boundary during the process. Corresponding to the grain size, the specific saturation magnetization (Ms) was increased due to the purity and crystallinity, and the reduction proportion of the pinned surface magnetic moments as a result of nanocrystal growth process. By doping Zn2+with different concentrations, the Ms of Ni0.5Zn0.5Fe2O4/ZnO NFs was higher during the grain growth and surface effect weakened. Compared with Ni0.5Zno.5Fe2O4nanoparticles, Nio.5Zn0.5Fe2O4/ZnO coaxial nanofiber has high coercive force, coercive force change trend with the increase of grain growth is first after the change is smooth, this may be due to grain growth will be in the process of grain from the effect due to the shift towards more domain.