Template-Free Synthesis of Magnetic Chains Self-Assembled from Urchin-Like Hierarchical Ni Nanostructures

Magnetic chains self-assembled from urchin-like hierarchical Ni nanostructures have been successfully synthesized by a simple hydrothermal method requiring 4 h at 115 degrees C without any template or surfactant. The individual urchin-like hierarchical nanostructures have an average diameter of 2-4 mu m and are composed of well-aligned sword-like nanopetals growing radially from the surfaces of the spherical particles. The products were characterized by means of X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy analysis (EDX), Fourier transform infrared (FTIR) spectroscopy, thermogravimetric and differential scanning calorimetric analysis (TGA-DSC). A rational formation mechanism of magnetic chains was proposed. Magnetic hysteresis measurements revealed that the as-synthesized Ni chain-like architectures display ferromagnetic behavior with saturation magnetization, remanent magnetization, and coercivity values of 52.58 emu/g, 5.82 emu/g, and 211.67 Oe, respectively.