Non-Equilibrium Zero Temperature Random Field Ising Model

Abstract

We present a numerical simulation of a zero temperature random field Ising model with single spin flip dynamics for the ferromagnetic as well as the anti-ferromagnetic system with quenched disorder in the presence of an external varying field. In ferromagnetic system, we study the behavior of the magnetization curve by varying the disorder in the system and the distribution of avalanche size. For large disorder we found that the magnetization curve is smooth continuous curve on a macroscopic scale and for small disorder there is a first order jump in the magnetization curve. Near the critical region where the magnetization curve changes from continuous to a discontinuous the avalanche size distribution follow a power law. In Anti-ferromagnetic system we found that area of the hysteresis loop is much smaller as compare to the ferromagnetic counterpart. The dynamics in ferromagnetic system is Abelian whereas in anti-ferromagnetic system it is non-Abelian.

Keywords: Gaussian distribution, macroscopic scale, magnetization curve, superconductors