Reversal of magnetisation in Ising ferromagnet by the field having gradient

TL;DR

This study investigates how a magnetic field gradient influences magnetization reversal in an Ising ferromagnet, revealing effects on metastable state lifetime, domain wall dynamics, and interface roughness through Monte Carlo simulations.

Contribution

It introduces a detailed simulation analysis of magnetization reversal under field gradients, highlighting new insights into domain wall behavior and interface properties.

Findings

Metastable state lifetime increases with field gradient.

Domain wall displacement follows a hyperbolic tangent function.

Interface roughness decays exponentially with gradient.

Abstract

We have studied the reversal of magnetisation in Ising ferromagnet by the field having gradient along a particular direction. We employed the Monte Carlo simulation with Metropolis single spin flip algorithm. The average lifetime of the metastable state was observed to increase with the magnitude of the gradient of applied field. In the high gradient regime, the system was observed to show two distinct region of up and down spins. The interface or the domain wall was observed to move as one increases the gradient. The displacement of the mean position of the interface was observed to increase with the gradient as hyperbolic tangent function. The roughness of the interface was observed to decay exponentially as the gradient increases. The number of spin flip per site was observed to show a discontinuity in the vicinity of the domain wall. The amount of the discontinuity was found to diverge with the system size as a power law fashion with an exponent 5/3.