Short-time domain-wall dynamics in the random-field Ising model with a driving field

N. J. Zhou, B. Zheng, and Y. Y. He

Phys. Rev. B 80, 134425 – Published 28 October 2009

Abstract

With Monte Carlo methods, we investigate the relaxation dynamics of a domain wall in the two-dimensional random-field Ising model with a driving field. The short-time dynamic behavior at the depinning transition is carefully examined, and the roughening process of the domain wall is observed. Based on the short-time dynamic scaling form, we accurately determine the transition field, static and dynamic exponents, and local and global roughness exponents. In contrast to the usual assumption, the results indicate that the domain interface does not belong to the universality class of the Edwards-Wilkinson equation. In particular, due to the dynamic effect of overhangs, the domain interface exhibits intrinsic anomalous scaling and spatial multiscaling behaviors, compatible with the experiments.