Force-Force Correlations in Disordered Magnets
Cathelijne ter Burg1, Felipe Bohn2, Gianfranco Durin3, Rubem Luis Sommer4, Kay Jörg Wiese1
1
CNRS-Laboratoire de Physique de
l'Ecole Normale Supérieure, PSL Research University, Sorbonne Universités, UPMC,
24 rue Lhomond, 75005 Paris, France.
2
Departamento de Física Teórica e Experimental, Universidade Federal do Rio Grande do Norte, 59078-900 Natal, RN, Brazil
3
Istituto Nazionale di Ricerca Metrologica, Torino, Italy
4 Centro Brasileiro de Pesquisas Físicas, Rua Dr. Xavier Sigaud 150, Urca, 22290-180 Rio de Janeiro, RJ, Brazil
Abstract
We study experimentally the force-force correlator in Barkhausen experiments. We observe two distinct universality classes, depending on the range of spin interactions. For short-ranged elasticity, we find the universal correlator predicted by the functional renormalization group in $d=2$. For long-ranged elasticity we observe its 1-loop solution.
In all cases force-force correlations grow linearly at small distances, as is assumed in the ABBM model, but in contrast to the latter are bounded at large distances. As a consequence, avalanches are anti-correlated, i.e. reduced in size, at short distances.
arXiv:2109.01197 [pdf]
Phys. Rev. Let. 129 (2022) 107205 [pdf]
Copyright (C)
by Kay Wiese. Last edited Sep. 7, 2022.