Equilibrium and non-equilibrium properties of synthetic metamagnetic films: A Monte Carlo study

TL;DR

This study uses Monte Carlo simulations to analyze the equilibrium and non-equilibrium behaviors of synthetic layered antiferromagnetic films, revealing consistent phase diagram features and dynamics across various stack configurations.

Contribution

It introduces a layered Ising model for multilayer synthetic antiferromagnets and systematically explores their phase diagrams and ordering dynamics.

Findings

Identified three stable phases with critical and tricritical points in phase diagrams.

Observed long-lived metastable states in thin films.

Calculated surface autocorrelation exponents for thick films.

Abstract

Synthetic antiferromagnets with strong perpendicular anisotropy can be modeled by layered Ising antiferromagnets. Accounting for the fact that in the experimental systems the ferromagnetic layers, coupled antiferromagnetically via spacers, are multilayers, we propose a description through Ising films where ferromagnetic stacks composed of multiple layers are coupled antiferromagnetically. We study the equilibrium and non-equilibrium properties of these systems where we vary the number of layers in each stack. Using numerical simulations, we construct equilibrium temperature$-$magnetic field phase diagrams for a variety of cases. We find the same dominant features (three stable phases, where one phase boundary ends in a critical end point, whereas the other phase boundary shows a tricritical point at which the transition changes from first to second order) for all studied cases. Using time-dependent quantities, we also study the ordering processes that take place after a temperature quench. The nature of long-lived metastable states are discussed for thin films, whereas for thick films we compute the surface autocorrelation exponent.