Spin dynamics from a constrained magnetic Tight-Binding model

A dynamics of the precession of coupled atomic moments in the tight-binding (TB) approximation is presented. By implementing an angular penalty functional in the energy that captures the magnetic effective fields self-consistently, the motion of the orientation of the local magnetic moments is observed faster than the variation of their magnitudes. This allows the computation of the effective atomic magnetic fields that are found consistent with the Heisenbergs exchange interaction, by comparison with classical atomistic spin dynamics on Fe, Co and Ni magnetic clusters.