Critical dynamics of randomly layered magnets

We report the results of large-scale Monte-Carlo simulations of the critical dynamics in the randomly layered Heisenberg model. This system has recently been reported to display an exotic phase transition controlled by an infinite-randomness critical point [Phys. Rev. B 81, 144407 (2010)]. In agreement with this, we found the critical dynamics to be ultraslow. At criticality, the time autocorrelation function decays only logarithmically with time while it follows a nonuniversal power-law in the Griffiths phase. We also study the case of XY spin symmetry where the interplay between the randomness and the Kosterlitz-Thouless physics leads to even stronger disorder effects.