Controlled synthesis of spherical and cubic magnetite nanocrystal clusters

• Magnetite nanocrystal clusters were prepared via a simple solvothermal method.
• The concentration of sodium acetate leads to the morphology variation from sphere to cube.
• Possible mechanisms are proposed to explain the morphology evolution.

Spherical Fe3O4 nanocrystal clusters were prepared via a simple solvothermal method using FeCl2·4H2O and NaOH as starting materials. When sodium acetate (NaAc) was added into the reaction system, the final products turned from sphere to cube. The as-prepared clusters are uniform in size. The possible mechanism was proposed to elucidate the changes of the clusters shape. The chemical compositions were characterized by X-ray diffraction (XRD). The morphology was determined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The magnetic properties were investigated on a superconducting quantum interference device (SQUID) magnetometer.