Morphology-controlled synthesis of magnetites with nanoporous structures and excellent magnetic properties

Different morphological single-crystal magnetites (Fe3O4) with a nanoporous structure, which exhibit excellent magnetic properties, have been synthesized by a polyol process. Both the type of polyol and the concentration of KOH play important roles in the formation of various morphologies. Cubic, truncated-octahedral, and octahedral shapes can be prepared by changing the concentration of the KOH solution in ethylene glycol. Sequentially, a series of submicro magnetites have been successfully obtained in the shape of spheres, truncated cubes, and equilateral octahedra by incrementally adjusting the concentration of KOH in glycerol. All the samples are ferromagnetic at 2 K but nearly paramagnetic at 300 K except the cubic sample. These Fe3O4 crystals may have a potential application as magnetic carriers for drug targeting because of their excellent soft-magnetic properties.