Soft X-ray Fluorescence Study of Buried Silicides in Antiferromagnetically Coupled Fe/Si Multilayer

TL;DR

This study uses soft x-ray fluorescence spectroscopy to analyze the electronic structure of buried silicide layers in Fe/Si multilayers, revealing differences based on magnetic coupling and confirming the metallic nature of the spacer layers.

Contribution

It provides new insights into the electronic states and phase composition of buried silicide layers in magnetic multilayers using advanced x-ray techniques.

Findings

Silicide phases differ in multilayers with and without antiferromagnetic coupling.

The silicide spacer layers are rich in iron and are metallic.

X-ray fluorescence and absorption data confirm the metallic nature of the silicide layers.

Abstract

Soft x-ray fluorescence spectroscopy has been employed to obtain information about the Si-derived valence band states of Fe/Si multilayers. The valence band spectra are quite different for films with and without antiferromagnetic interlayer exchange coupling, demonstrating that these multilayers have different silicide phases in their spacer layers. Comparison with previously published fluorescence data on bulk iron silicides shows that the Fe concentration in the silicide spacer layers is substantial. Near-edge x-ray absorption data on antiferromagnetically coupled multilayers in combination with the fluorescence data demonstrate unambiguously that the silicide spacer layer in these films is metallic. These results on the electronic structure of buried layers in a multilayer film exemplify the wide range of experiments made possible by new high-brightness synchrotron sources.