Monte Carlo investigation of the magnetic anisotropy in Fe/Dy multilayers

TL;DR

This study uses Monte Carlo simulations to explore how the magnetic anisotropy in Fe/Dy multilayers depends on their structure and composition, revealing the effects of concentration profiles and anisotropy constants on magnetic behavior.

Contribution

It introduces a detailed Monte Carlo model linking magnetic anisotropy to concentration profiles and local structures in Fe/Dy multilayers, aligning with experimental observations.

Findings

A compensation point occurs with an abrupt concentration profile.

Increased Dy anisotropy constant enhances atomic moment noncollinearity.

Magnetisation profiles are inhomogeneous and depend on concentration.

Abstract

By Monte Carlo simulations in the canonical ensemble, we have studied the magnetic anisotropy in Fe/Dy amorphous multilayers. This work has been motivated by experimental results which show a clear correlation between the magnetic perpendicular anisotropy and the substrate temperature during elaboration of the samples. Our aim is to relate macroscopic magnetic properties of the multilayers to their structure, more precisely their concentration profile. Our model is based on concentration dependent exchange interactions and spin values, on random magnetic anisotropy and on the existence of locally ordered clusters that leads to a perpendicular magnetisation. Our results evidence that a compensation point occurs in the case of an abrupt concentration profile. Moreover, an increase of the noncollinearity of the atomic moments has been evidenced when the Dy anisotropy constant value grows. We have also shown the existence of inhomogeneous magnetisation profiles along the samples which are related to the concentration profiles.