Parametrization of the magnetic energy at the atomic level
R. Drautz, M. Fahnle.
Physical Review B, 72, 212405, (2005)
We parametrize the adiabatic magnetic energy of generalized classical spins for the important special case of zero spin-orbit coupling and no applied external field. The expansion classifies the classical Heisenberg model as a first order approximation to the energy; extensions of the Heisenberg model in literature are shown to be of second order in the classical limit of our parametrization. The expressions for a third-order approximation to the magnetic energy are derived.
Keyword(s): MULTICOMPONENT SYSTEMS