Modeling the Magnetic Properties of 1D Arrays of FePc Molecules

We investigate the magnetic properties of Fe Phthalocyanines (FePc) that are experimentally arranged in quasi one-dimensional chains when they are grown in thin films or powders. By means of DFT calculations we reproduce the structural parameters found in experiments, and then we build a generalized Heisenberg magnetic model with single ion anisotropy, and calculate its parameters. The results show a anisotropic exchange interaction J between FePc molecules, and an easy plane single ion anisotropy D. By means of Monte Carlo simulations, with this model, we found an explanation to the non-saturation of the magnetization found at high fields, which we interpret is due to the anisotropic exchange interaction J. Finally, we also investigate the presence of magnetic solitons versus temperature and magnetic field. This results provide additional evidence that FePc is a soliton bearing molecular compound, with solitons easily excited mainly in the molecular xy plane.