Soft-x-ray fluorescence study of buried silicides in antiferromagnetically coupled Fe/Si multilayers.

Soft x-ray uorescence spectroscopy has been employed to obtain information about the Si-derived valence band states of Fe/Si multilayers. The valence band spectra are quite diierent for lms with and without antiferromagnetic interlayer exchange coupling, demonstrating that these multilayers have different silicide phases in their spacer layers. Comparison with previously published uorescence data on bulk iron silicides shows that the Fe concentration in the silicide spacer layers is substantial. Near-edge x-ray absorption data 1 on antiferromagnetically coupled multilayers in combination with the uores-cence data demonstrate unambiguously that the silicide spacer layer in these lms is metallic. These results on the electronic structure of buried layers in a multilayer lm exemplify the wide range of experiments made possible by new high-brightness synchrotron sources.