Dynamic behavior of a magnetic system driven by an oscillatory external temperature

Abstract

The dynamic effects on a magnetic system exposed to a time-oscillating external temperature are studied using Monte Carlo simulations on the classic 2D Ising Model. The time dependence of temperature is defined as T (t) = T0 + A · sin(2πt/τ ). Magnetization M(t) and period-averaged magnetization hQi are analyzed to characterize out-of-equilibrium phenomena. Hysteresis-like loops in M(t) are observed as a function of T (t). The area of the loops is well-defined outside the critical Ising temperature (Tc) but takes more time to close it when the system crosses the critical curve. Results show a power-law dependence of hQi (the averaged area of loops) on both L and τ , with exponents α = 1.0(1) and β = 0.70(1), respectively. Furthermore, the impact of shifting the initial temperature T0 on hQi is analyzed, suggesting the existence of an effective τ -dependent critical temperature Tc(τ ). A scaling law behavior for hQi is found on the base of this τ -dependent critical temperature.