Hysteresis mediated by a domain wall motion

TL;DR

This paper investigates the hysteresis phenomena in domain wall motion within random media, analyzing how various factors like temperature and driving frequency influence the behavior and phase transitions of the domain walls.

Contribution

It provides a theoretical framework for understanding hysteresis and phase transitions in domain wall dynamics, including scaling laws and critical behavior near the mobility threshold.

Findings

Hysteresis characteristics obey scaling laws near the mobility threshold.

Finite temperature smears the threshold, introducing thermally activated hysteresis.

Non-adiabatic driving induces hysteresis in both position and velocity of domain walls.

Abstract

The position of an interface (domain wall) in a medium with random pinning defects is not determined unambiguously by a current value of the driving force even in average. Based on general theory of the interface motion in a random medium we study this hysteresis, different possible shapes of domain walls and dynamical phase transitions between them. Several principal characteristics of the hysteresis, including the coercive force and the curves of dynamical phase transitions obey scaling laws and display a critical behavior in a vicinity of the mobility threshold. At finite temperature the threshold is smeared and a new range of thermally activated hysteresis appears. At a finite frequency of the driving force there exists a range of the non-adiabatic regime, in which not only the position, but also the average velocity of the domain wall displays hysteresis.