Synthesis and magnetic properties of monodisperse magnetite nanocubes

The monodisperse Fe3O4 nanocubes with controllable sizes from 6.5 to 30.0 nm have been synthesized in one pot. The shape-induced texture of the self-assembled nanocube superlattices has been deposited onto substrates by a convective assembly technique. The cubelike shapes affect the crystalline orientation of individual particles within the self-assembled superlattices compared with the nanoparticles with an isotropic spherical shape. The nanocubes with a size less than 25 nm show a typical superparamagnetic behavior at room temperature. Comparison of the hysteresis loop at 5 K of cubes with different sizes reveals a size-dependent behavior of saturation magnetization and coercivity. (C) 2008 American Institute of Physics.