Influence of uncorrelated overlayers on the magnetism in thin itinerant-electron films

TL;DR

This study explores how nonmagnetic overlayers influence the magnetic properties of thin itinerant-electron films, revealing significant effects on Curie temperatures and long-range oscillatory polarization behaviors.

Contribution

It introduces a theoretical analysis of uncorrelated overlayers' impact on ferromagnetic thin films using the Hubbard model and spectral density approach.

Findings

Nonmagnetic layers significantly alter Curie temperatures.

Coupling depends on band occupation, not the number of layers.

Induced polarization exhibits long-range oscillatory behavior.

Abstract

The influence of uncorrelated (nonmagnetic) overlayers on the magnetic properties of thin itinerant-electron films is investigated within the single-band Hubbard model. The Coulomb correlation between the electrons in the ferromagnetic layers is treated by using the spectral density approach (SDA). It is found that the presence of nonmagnetic layers has a strong effect on the magnetic properties of thin films. The Curie temperatures of very thin films are modified by the uncorrelated overlayers. The quasiparticle density of states is used to analyze the results. In addition, the coupling between the ferromagnetic layers and the nonmagnetic layers is discussed in detail. The coupling depends on the band occupation of the nonmagnetic layers, while it is almost independent of the number of the nonmagnetic layers. The induced polarization in the nonmagnetic layers shows a long-range decreasing oscillatory behavior and it depends on the coupling between ferromagnetic and nonmagnetic layers.