Title: Critical slowing down in random anisotropy magnets
Author(s):

	M.Dudka (Institute for Condensed Matter Physics of the National Academy of Sciences of Ukraine, 79011 Lviv, Ukraine; Institut für Theoretische Physik, Johannes Kepler Universität Linz, A-4040, Linz, Austria) ,
	R.Folk (Institut für Theoretische Physik, Johannes Kepler Universität Linz, A-4040, Linz, Austria) ,
	Yu.Holovatch (Institute for Condensed Matter Physics of the National Academy of Sciences of Ukraine, 79011 Lviv, Ukraine; Institut für Theoretische Physik, Johannes Kepler Universität Linz, A-4040, Linz, Austria; Ivan Franko National University of Lviv, 79005 Lviv, Ukraine) ,
	G.Moser (Institut für Physik und Biophysik, Universität Salzburg, A-5020 Salzburg, Austria) ,

We study the purely relaxational critical dynamics with non-conserved order parameter (model A critical dynamics) for three-dimensional magnets with disorder in a form of the random anisotropy axis. For the random axis anisotropic distribution, the static asymptotic critical behaviour coincides with that of random site Ising systems. Therefore the asymptotic critical dynamics is governed by the dynamical exponent of the random Ising model. However, the disorder effects considerably the dynamical behaviour in the non-asymptotic regime. We perform a field-theoretical renormalization group analysis within the minimal subtraction scheme in two-loop approximation to investigate asymptotic and effective critical dynamics of random anisotropy systems. The results demonstrate the non-monotonic behaviour of the dynamical effective critical exponent z_eff.

Key words: critical dynamics, disordered systems, random anisotropy, renormalization group
PACS: 05.50.+q, 05.70.Jk, 61.43.-j, 64.60.Ak, 64.60.Ht