Solvothermal synthesis of cauliflower-like CoNi microstructures with enhanced magnetic property

•Cauliflower-like CoNi microstructures were synthesized via a solvothermal method.•No template or surfactant was used.•Citric acid served as complex agent.•Such CoNi microstructures showed significantly enhanced coercivity of 178.3 Oe.

Novel cauliflower-like CoNi microstructures assembled by many thick petals were synthesized via a solvothermal process at 120 °C with the assistance of citric acid as complex agent. The obtained samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and vibrating sample magnetometry (VSM) techniques. It was found that the amount of reducing agent and solvothermal reaction time played important roles in the formation of cauliflower-like CoNi alloy assemblies. Magnetic hysteresis measurement at room temperature revealed that CoNi cauliflowers exhibited a ferromagnetic property with a coercivity of 178.3 Oe, which was much higher than those of CoNi micro/nanostructures reported in recent literatures. Our work may shed light on the design and preparation of other nanomaterials with similar complex morphology.

Graphical abstractNovel cauliflower-like CoNi microstructures assembled by many thick petals were synthesized via a solvothermal process at 120 °C with the assistance of citric acid as complex agent. Such CoNi cauliflowers displayed ferromagnetic behaviors at room temperature with an enhanced coercivity of 178.3 Oe.Figure optionsDownload full-size imageDownload as PowerPoint slide