Monte Carlo study of the domain kinetics of the Ising model with random coupling constants.

Abstract

Monte Carlo simulations are used to study the domain kinetics of the two-dimensional ferromagnetic Ising model with random coupling constants which have a Gaussian distribution with a mean value J and a width \ensuremath{\Delta}J. When this system is quenched to low temperature, the evolution of initially circular domains is observed. We find that the relation between the decay time t and size L of the domain is given by L(T)=${\mathrm{Ct}}^{a}$, where a is an exponent less than 1/2 varying with \ensuremath{\Delta}J and the quenching temperature T, or 1/2 for the pure system. The larger the \ensuremath{\Delta}J and the lower the temperature T is, the smaller the exponent becomes.