History-Induced Critical Behavior in Disordered Systems

TL;DR

This paper investigates how history and long-range fields influence critical behavior in disordered magnetic systems, revealing distinct subloop behaviors and noise characteristics through large-scale simulations.

Contribution

It demonstrates the emergence of self-organized criticality and history-induced critical scaling in the random-field Ising model with and without long-range fields.

Findings

Power law noise distributions in subloops with LR fields

Critical scaling in avalanche sizes without LR fields

Large-scale simulations of over 10^8 spins

Abstract

Barkhausen noise as found in magnets is studied both with and without the presence of long-range (LR) demagnetizing fields using the non-equilibrium, zero-temperature random-field Ising model. Two distinct subloop behaviors arise and are shown to be in qualitative agreement with experiments on thin film magnets and soft ferromagnets. With LR fields present subloops resemble a self-organized critical system, while their absence results in subloops that reflect the critical point seen in the saturation loop as the system disorder is changed. In the former case, power law distributions of noise are found in subloops, while in the latter case history-induced critical scaling is studied in avalanche size distributions, spin-flip correlation functions, and finite-size scaling of the second moments of the size distributions. Results are presented for simulations of over 10^8 spins.