Dynamic effect of overhangs and islands at the depinning transition in two-dimensional magnets

TL;DR

This study uses Monte Carlo simulations to analyze the short-time dynamics of domain-wall motion in 2D random-field Ising models, revealing how overhangs and islands influence the depinning transition and universality class.

Contribution

It provides a detailed investigation of overhangs and islands effects at the depinning transition, identifying their critical role in the universality class of the model.

Findings

Overhangs and islands reach maximum effect at the depinning transition.

The dynamics suggest a different universality class from Edwards-Wilkinson with quenched disorder.

Accurate determination of the depinning field and critical exponents.

Abstract

With the Monte Carlo methods, we systematically investigate the short-time dynamics of domain-wall motion in the two-dimensional random-field Ising model with a driving field ?DRFIM?. We accurately determine the depinning transition field and critical exponents. Through two different definitions of the domain interface, we examine the dynamics of overhangs and islands. At the depinning transition, the dynamic effect of overhangs and islands reaches maximum. We argue that this should be an important mechanism leading the DRFIM model to a different universality class from the Edwards-Wilkinson equation with quenched disorder