The role of stationarity in magnetic crackling noise

TL;DR

This paper investigates how stationarity affects the statistical properties of Barkhausen noise signals in ferromagnetic materials, revealing that non-stationary conditions lead to different avalanche exponents and providing a model-based explanation.

Contribution

It demonstrates the impact of stationarity on avalanche statistics in Barkhausen noise and offers a quantitative model to explain experimental observations.

Findings

Stationary signals yield typical avalanche exponents ($ au=1.3$, $eta=1.5$).

Non-stationary signals show significantly larger exponents ($ au=1.7$, $eta=2.2$).

A depinning model explains the experimental differences.

Abstract

We discuss the effect of the stationarity on the avalanche statistics of Barkhuasen noise signals. We perform experimental measurements on a Fe$_{85}$B$_{15}$ amorphous ribbon and compare the avalanche distributions measured around the coercive field, where the signal is stationary, with those sampled through the entire hysteresis loop. In the first case, we recover the scaling exponents commonly observed in other amorphous materials ($\tau=1.3$, $\alpha=1.5$). while in the second the exponents are significantly larger ($\tau=1.7$, $\alpha=2.2$). We provide a quantitative explanation of the experimental results through a model for the depinning of a ferromagnetic domain wall. The present analysis shed light on the unusually high values for the Barkhausen noise exponents measured by Spasojevic et al. [Phys. Rev. E 54 2531 (1996)].