Quantitative scaling of magnetic avalanches
Gianfranco Durin1,2, Felipe Bohn3, Marcio A. Correa3, Rubem Luis Sommer4, Pierre Le Doussal5, Kay Jörg Wiese5
1
Istituto Nazionale di Ricerca Metrologica, Strada delle Cacce 91, 10135 Torino, Italy
2
ISI Foundation, Via Alassio 11/c, 10126 Torino, Italy
3 Departamento de Física Teórica e Experimental, Universidade Federal do Rio Grande do Norte, 59078-900 Natal, RN, Brazil
4 Centro Brasileiro de Pesquisas Físicas, Rua Dr. Xavier Sigaud 150, Urca, 22290-180 Rio de Janeiro, RJ, Brazil
5
CNRS-Laboratoire de Physique Théorique de
l'Ecole Normale Supérieure,
24 rue Lhomond, 75005 Paris, France.
Abstract
We provide the first quantitative comparison between Barkhausen noise experiments and recent predictions from the theory of avalanches for pinned interfaces, both in and beyond mean-field. We study different classes of soft magnetic materials: polycrystals and amorphous samples, characterized by long-range and short-range elasticity, respectively; both for thick and thin samples, i.e. with and without eddy currents. The temporal avalanche shape at fixed size, and observables related to the joint distribution of sizes and durations, are analyzed in detail. Both long-range and short-range samples with no eddy currents are fitted extremely well by the theoretical predictions. In particular, the short-range samples provide the first reliable test of the theory beyond mean-field. The thick samples show systematic deviations from the scaling theory, providing unambiguous signatures for the presence of eddy currents.
arXiv:1601.01331v3 [pdf]
Phys. Rev. Lett. 117 (2016) 087201 [pdf]
Copyright (C)
by Kay Wiese. Last edited Aug 17, 2016.