Magnetization of small dot arrays with dipolar interacting nanoparticles

We study the magnetization of a patterned array of cylinders using the Landau-Lifshitz-Gilbert equation. The direction of the external magnetizing field may vary from in-plane orientation to out-of-plane orientation. The magnetization is found to depend on the direction of the external magnetic field and the strength of dipolar interaction. The hysteresis loops show strongly size-dependent effects, as a result of the competition among the dipolar interaction, perpendicular anisotropy and Zeeman energy. The remanence and the switching field are anisotropic with respect to the direction of the applied magnetic field.