Barkhausen instabilities from labyrinthine magnetic domains

TL;DR

This paper investigates the scaling behavior of Barkhausen avalanches in labyrinthine magnetic domains, revealing how competing forces influence avalanche sizes and proposing testable predictions related to film thickness and disorder.

Contribution

It introduces a phase field model that explains the bounded avalanche scaling due to dipolar and exchange interactions, reconciling experimental discrepancies.

Findings

Avalanche scaling is limited by characteristic lengthscales.

Good agreement between model predictions and experimental data.

Predictions on how film thickness and disorder affect avalanche behavior.

Abstract

Experimental investigations of the scaling behavior of Barkhausen avalanches in out-of-plane ferromagnetic films yield widely different results for the values of the critical exponents despite similar labyrinthine domain structures, suggesting that universality may not hold for this class of materials. Analyzing a phase field model for magnetic reversal, we show that avalanche scaling is bounded by characteristic lengthscales arising from the competition between dipolar forces and exchange interactions. We compare our results with the experiments and find a good qualitative and quantitative agreement, reconciling apparent contradictions. Finally, we make some prediction, amenable to experimental verification, on the dependence of the avalanches behavior from the film thickness and disorder.