Formation of Ni microflowers constructed by solid-particle-core and petal-shell with increased coercivity

Abstract Hierarchical nickel microflowers were synthesized by a facile hydrothermal method using sodium hypophosphite as a mild reducing reagent and sodium tartrate as a complexing reagent. The flowers having a size ranging from 1.2 to 1.5 µm were constructed by a novel solid-particle-core and petal-shell. The assembled rose-like petals possessed a thin thickness and seemed to be flexible like silk. Room temperature magnetic characterization of the nickel flowers demonstrated ferromagnetic property with an increased coercivity of 488.3 Oe, which was ascribed to the highly anisotropic shape of hierarchically flower-like microstructures. This work provides a simple strategy to fabricate stable nickel 3D flowers composed of numerous petals, and can be extended to the synthesis of other magnetic nanomaterials.