Dresden 2006 – scientific programme
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DY: Dynamik und Statistische Physik
DY 44: Critical Phenomena and Phase Transitions III
DY 44.3: Talk
Thursday, March 30, 2006, 15:15–15:30, H\"UL 186
Critical Dynamics of Magnets with Random Anisotropy — •Reinhard Folk1, Maxim Dudka2, Yurij Holovatch2, and Günter Moser3 — 1Institute for Theoretical Physics University Linz Austria — 2Institute for Condensed Matter Physics National Academy of Sciences of Ukraine Lviv Ukraine — 3Molecular Biology University of Salzburg Salzburg Austria
We investigate the relaxational critical dynamics with non-conserved order parameter coupled to the energy density (model C critical dynamics) for three-dimensional magnets with disorder in a form of a random anisotropy axis. For a random distribution of cubic symmetry, 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 influences 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 order to investigate the asymptotic and effective critical dynamics of random anisotropy systems. The results demonstrate a rich non-monotonic behaviour of the dynamical effective critical exponent zeff. The limiting case of a purely relaxational dynamics [1] is also considered. (Work supported by the Fonds zur Foerderung der wissenschaftlichen Forschung Project No. P16574)
[1] M. Dudka, R. Folk, Yu. Holovatch, and G. Moser, submitted to Condensed Matter Physics (Ukraine) 2005 (cond-mat/0506325)