Synthesis and hierarchical assembly of CoNi flowery particles

Novel chain-like CoNi hierarchical structures assembled from flowery particles were successfully synthesized via a hydrothermal synthetic route without surfactants or external magnetic fields. The effect of synthetic parameters, including citrate content, NaOH concentration, reaction temperature and time, on the formation and morphologies of the CoNi assemblies were investigated. The experimental results showed that the morphologies of the assemblies could be adjusted by the NaOH concentration and temperature. Compared with the isolated particles, the saturation magnetization of the chain-like assemblies decreased from 132.6 to 114.5 emu g−1, while the coercivity increased from 84.4 to 260.7 Oe.