Controlled Synthesis of 3D and 1D Nickel Nanostructures Using an External Magnetic Field Assisted Solution-Phase Approach

Nickel three-dimensional (3D) urchin-like particles and one-dimensional (1D) chainlike nanowires are selectively synthesized by an in situ magnetic-field-directed solution-phase method at ambient conditions. The results indicate that the morphology of the products strongly depends on the external magnetic-field distribution. The urchin-like particle is composed of a spheric core connected by spear-shaped branches under the nonuniform magnetic field, while the chainlike nanowire is formed through 1D alignment of spheres with the aid of parallel magnetic-field distribution during the reaction. The branch lengths and the whole size of the urchin-like particles can be tailored by adjusting the pH value and reaction temperature, respectively. The magnetic properties of the urchin-like particles are studied in detail as well and the results reveal that the saturated magnetization and coercivity are strongly related to the corresponding microstructure. This work provides a simple and effective strategy to modulate the morphology of the magnetic materials through the external magnetic-field force.