Dynamic magnetization-reversal transition in the Ising model

Abstract

We report the results of mean field and the Monte Carlo study of the dynamic magnetization-reversal transition in the Ising model, brought about by the application of an external field pulse applied in opposition to the existing order before the application of the pulse. The parameters controlling the transition are the strength h_p and the duration Δt of the pulse. In the mean field case, an approximate analytical expression is obtained for the phase boundary which agrees well with that obtained numerically in the small Δt and large T limit. The order parameter of the transition has been identified, and is observed to vary continuously near the transition. The order parameter exponent β was estimated both for the mean field (β=1) and the Monte Carlo (β=0.90±0.02 in two dimensions) cases. The transition shows a "critical slowing down" type behavior near the phase boundary with diverging relaxation time. The divergence was found to be logarithmic in the mean field case and exponential in the Monte Carlo case. The finite size scaling technique was employed to estimate the correlation length exponent ν (=1.5±0.3 in two dimensions) in the Monte Carlo case.