Monte Carlo simulation of the irreversible growth of magnetic thin films

TL;DR

This paper models the irreversible growth of magnetic thin films using Monte Carlo simulations, revealing temperature-dependent domain formation, spontaneous magnetization reversal, and phase transitions akin to the Ising model.

Contribution

It introduces a Monte Carlo simulation framework for magnetic film growth, capturing domain dynamics and phase transitions during irreversible deposition.

Findings

Ordered magnetic domains form at low temperatures.

Spontaneous magnetization reversal occurs with a characteristic length scale.

A transition between ordered and disordered states is observed at higher temperatures.

Abstract

The growth of magnetic films with ferromagnetic interactions between nearest-neighbor spins is studied in $(d+1)-$dimensional rectangular geometries for $d = 1,2$. Magnetic films are grown irreversibly by adding spins at the boundaries of the growing interface. The orientation of the added spins depends on both the energetic interaction with already deposited spins and the temperature, through a Boltzmann factor. At low temperatures thin films, of thickness $L$, are constituted by a sequence of well ordered magnetic domains. Spins belonging to each domain, of average length $l_{D} \gg L$, have mostly the same orientation, but consecutive domains have opposite magnetization. Such kind of ``spontaneous magnetization reversal'' during the growth process has a short characteristic length $l_{R}$, such that $l_{D} \gg l_{R} \sim L$. At higher temperatures, a transition between ordered and disordered states is also observed. The emerging behavior is compared to that of the equilibrium Ising model.