Aging in a two-dimensional Ising model with dipolar interactions

Aging in a two-dimensional Ising spin model with both ferromagnetic exchange and antiferromagnetic dipolar interactions is established and investigated via Monte Carlo simulations. The behavior of the autocorrelation function ${C(t,t}_w)$ is analyzed for different values of the temperature, the waiting time $t_w$ and the quotient $\delta {=J}_0{/J}_d,$ $J_0$ and $J_d$ being the strength of exchange and dipolar interactions, respectively. Our results show that this nondisordered model presents a slow nonequilibrium dynamics which, depending on the values of δ, is consistent either with a linear scaling ${t/t}_w$ of the correlation function or with a logaritmic scaling $\ln \mathrm{}\left(t\right)/\ln {(t}_w)$ which is usually associated with activated dynamics scenarios in disordered systems.