Monte Carlo Simulations of ABC Stacked Kagome Lattice Thin Films

TL;DR

This study uses Monte Carlo simulations to analyze how anisotropies affect the magnetic properties of ABC stacked kagome lattice thin films, revealing surface and bulk spin behaviors relevant to exchange bias phenomena.

Contribution

It introduces a detailed Monte Carlo simulation approach to study anisotropy effects in ABC stacked kagome thin films, highlighting surface-bulk spin interactions.

Findings

Surface spins align along the surface normal axis due to axial anisotropy.

Surface anisotropy influences interior layers weakly through exchange coupling.

Results relate to exchange bias in IrMn₃ thin films.

Abstract

Properties of thin films of geometrically frustrated ABC stacked antiferromagnetic kagome layers are examined using Metropolis Monte Carlo simulations. The impact of having an easy-axis anisotropy on the surface layers and cubic anisotropy in the interior layers is explored. The spin structure at the surface is shown to be different from that of the bulk 3D fcc system, where surface axial anisotropy tends to align spins along the surface [111] normal axis. This alignment tendency then propagates only weakly to the interior layers through exchange coupling. Results are shown for the specific heat, magnetization and sub-lattice order parameters for both surface and interior spins in three and six layer films as a function of increasing axial surface anisotropy. Relevance to the exchange bias phenomenon in IrMn$_3$ thin films is discussed.