Preparation and magnetic property of chain-like cobalt microrods

Chain-like cobalt microrods with length of 10–13 μm were solvothermally synthesized in water and ethanol mixed solution at 150 °C for 20 h. Sodium hypophosphite was used as reducing reagent and cetyltrimethylammonium bromide molecules served as cross-linkers. The chain-like cobalt microrods possessed hcp phase structure and were linearly assembled by several beads, and each bead was composed of many nanoparticles. The formation mechanism of such novel cobalt was discussed on the basis of controlled experiments. Compared to the cobalt bulk, the chain-like cobalt microrods obtained in this work possessed a decreased saturation magnetization (Ms, 151.9 emu/g) but an enhanced coercivity (Hc, 139.5 Oe) probably due to their novel morphology.