  A numerical technique combining Monte Carlo and molecular dynamics
simulations is used for the first time to examine the complex critical dynamics
of models of ferromagnetic gadolinium in which both strong exchange
interactions and relativistic effects of several different types are taken into
account. A finitesize scaling technique is used to calculate the corresponding
dynamic critical exponents. The role played by isotropic dipole-dipole
interaction in the critical behavior of gadolinium is evaluated. The results
obtained provide an explanation for the anomalous dynamic critical behavior of
gadolinium.
