Influence of Roughening Transition on Magnetic Ordering

Abstract: In the literature of magnetic phase transitions, in addition to a critical point, existence of another special point has been discussed. This is related to the broadening of interface between two different ordering phases and is referred to as the point of roughening transition. While there exists good understanding on equilibrium properties associated with this transition, influence of this on nonequilibrium dynamics has not been investigated. In this paper we present comprehensive results, from Monte Carlo simulations, on coarsening dynamics in a system, over a wide range of temperature, in space dimension d = 3, for which there exists roughening transition at a nonzero temperature. State-of-the-art analysis of the simulation data, on structure, growth and aging, shows that the onset of unexpected glass-like slow dynamics in this system, that has received much attention in recent times, for quenches to zero temperature, actually occurs at this transition point. This demonstrates an important structure-dynamics connection in phase-ordering dynamics. We compare the key results with those from d = 2, for which there exists no non-zero roughening transition temperature. Absence of the above mentioned anomalous features in the latter dimension places our conjecture on the role of roughening transition on a firmer footing.