Dynamical fractal and anomalous noise in a clean magnetic crystal

Authors: Jonathan N. Hallén, Santiago A. Grigera, D. Alan Tennant, Claudio Castelnovo, Roderich Moessner

Published: 2022-12-15

DOI: 10.1126/science.add1644

Source: Full article


Abstract

Fractals—objects with noninteger dimensions—occur in manifold settings and length scales in nature. In this work, we identify an emergent dynamical fractal in a disorder-free, stoichiometric, and three-dimensional magnetic crystal in thermodynamic equilibrium. The phenomenon is born from constraints on the dynamics of the magnetic monopole excitations in spin ice, which restrict them to move on the fractal. This observation explains the anomalous exponent found in magnetic noise experiments in the spin ice compound Dy