Self organized criticality of magnetic avalanches in disordered ferrimagnetic material

TL;DR

This study investigates magnetic avalanches in a disordered ferrimagnetic alloy, revealing scale-invariant jumps in magnetization that are modeled by a spin system exhibiting self-organized criticality.

Contribution

It demonstrates the occurrence of self-organized criticality in magnetic avalanches of a ferrimagnetic alloy through experimental observation and computational modeling.

Findings

Magnetic jumps follow a power-law distribution.

Jumps are stochastic with no temporal correlation.

Model reproduces scale-invariant avalanche behavior.

Abstract

We observe multiple step-like jumps in a Dy-Fe-Ga-based ferrimagnetic alloy in its magnetic hysteresis curve at 2 K. The observed jumps have a stochastic character with respect to their magnitude and the critical field of occurrence, and the jumps do not show any temporal effect. The jump size distribution follows a power law variation indicating the scale invariance nature of the jumps. We have invoked a simple two-dimensional random bond Ising-type spin system to model the dynamics. Our computational work can qualitatively reproduce the jumps and their scale invariant character. It also elucidates that the flipping of antiferromagnetically coupled Dy and Fe clusters is responsible for the observed discrete avalanche-like features in the hysteresis loop. These characteristics indicate that the present phenomenon can be well described within the realm of self-organized criticality