Study of magnetic clusters using a tight binding molecular dynamics approach

The tight-binding molecular-dynamics (TBMD) method has been proved to be a useful tool in the study of semiconductors. Recently, we extended this method to the study of transition metal systems. Our applications to non-magnetic clusters of transition metal atoms gave results for the binding energies, bond lengths and vibration frequencies of Ni-n clusters (n upto 55) in very good agreement with both theory and experiment. In the present work we extend the applicability of the formalism to include the study of magnetic properties of the Ni-n, Fe-n, and Co-n clusters (n less than or equal to 55). This is achieved by incorporating an exchange splitting term in the TBMD Hamiltonian. It is shown that the results obtained for the magnetic moment (per atom) for Ni, Fe and Co clusters are in very good agreement with recent experimental data, thus establishing the validity of our scheme in the treatment of magnetic systems and/or their alloys.