Hysteresis in an Ising model with mobile bonds

TL;DR

This paper investigates hysteresis phenomena in a disordered Ising model with mobile bonds, revealing how bond diffusion alters hysteresis loops and relates to domain dynamics and experimental anomalies.

Contribution

It introduces a model allowing bond diffusion in an Ising system, showing how this affects hysteresis behavior and links to experimental figure-eight anomalies.

Findings

Diffusion changes saturation hysteresis to a figure-eight loop.

The figure-eight's features depend on temperature and dynamics.

Main avalanche relates to disappearance of hidden order.

Abstract

Hysteresis is studied in a disordered Ising model in which diffusion of antiferromagnetic bonds is allowed in addition to spin flips. Saturation behavior changes to a figure-eight loop when diffusion is introduced. The upper and lower fields delimiting the figure-eight are determined by the Hamiltonian, while its surface and the crossing point depend on the temperature and details of the dynamics. The main avalanche is associated with the disappearance of hidden order. Some experimental observations of figure-eight anomalies are discussed. It is argued they are a signal of a transient rearrangement of domain couplings, characteristic of amorphous and/or magnetically soft samples, and similar to evolution of kinetic glasses.