Fluctuation Cumulant Behavior for the Field-Pulse Induced Magnetisation-Reversal Transition in Ising Models

TL;DR

This study investigates the universality class of the dynamic magnetisation-reversal transition in a 2D Ising model induced by a field pulse, revealing a shift from non-mean-field to mean-field behavior depending on temperature and pulse width.

Contribution

It provides the first detailed analysis of the fluctuation cumulant behavior across the transition, identifying different universality classes in the dynamic phase transition.

Findings

Cumulant crossing point indicates the transition and universality class.

Transition exhibits non-mean-field behavior at low temperature and pulse width.

Transition appears mean-field like at higher temperature and pulse width.

Abstract

The universality class of the dynamic magnetisation-reversal transition, induced by a competing field pulse, in an Ising model on a square lattice, below its static ordering temperature, is studied here using Monte Carlo simulations. Fourth order cumulant of the order parameter distribution is studied for different system sizes around the phase boundary region. The crossing point of the cumulant (for different system sizes) gives the transition point and the value of the cumulant at the transition point indicates the universality class of the transition. The cumulant value at the crossing point for low temperature and pulse width range is observed to be significantly less than that for the static transition in the same two-dimensional Ising model. The finite size scaling behaviour in this range also indicates a higher correlation length exponent value. For higher temperature and pulse width range, the transition seems to fall in a mean-field like universality class.