Magnetic properties of cube-shaped Fe3O4 nanoparticles in dilute, 2D, and 3D assemblies

The behavior of cube-shaped Fe3O4 nanoparticles is compared with that of similar spherical particles to reveal the effects of surface and shape anisotropy. Magnetostatic interactions in nanocube and nanosphere assemblies are analyzed in terms of an interaction parameter and an activation volume, and compared with theoretical predictions for the magnetic ground state of point dipole arrays with different lattice symmetries.