Frey, Erwin; Schwabl, F.
Critical dynamics of ferromagnets.
In: Journal de physique, Vol. 49, Nr. 8: S. 1531-1536
The crossover in the dynamics from isotropic to dipolar critical behaviour has been a matter of debate over many years. We review a mode coupling theory for dipolar ferromagnets which gives a unified explanation of the seemingly contradictory experimental situation. The shape functions, the scaling functions for the damping coefficients and the precise position of the crossover are computed. Below Tc only the exchange interaction is taken into account.