Facile Synthesis and Growth Mechanism of Flowerlike Ni−Fe Alloy Nanostructures

Flowerlike Ni−Fe alloy nanostructures composed of nanorods have been synthesized via a facile hydrothermal approach at relatively low temperature (100 °C) independent of surfactants or external magnetic field. The concentrations of NaOH and FeCl 3 play a crucial role in determining the morphology of the Ni−Fe alloy via adjusting the reaction rate. The excessive amount of NaOH favors the formation of alloyed phase without segregation. Such flowerlike architectures follow a stepwise growth mechanism with initial formation of nanocores aggregated from nuclei and a subsequent site-specific anisotropic growth of nanorods along their easy magnetic axis under kinetic control. The Ni−Fe flowers showed enhancement of their ferromagnetic properties, which may be attributed to the anisotropic shape and the incorporation of Fe compared to pure Ni. Our work may shed light on the designed fabrication of complex 3D architectures of other alloyed materials.