XPS Valence Band and Core Level Spectra of Sputter-Deposited Fe–Cu, Fe–Ag and Fe–Cu–Ag Alloy Films

Abstract

Valence band and core-level characteristics of sputter-deposited Fe–Cu, Fe–Ag and Fe–Cu–Ag alloy films have been studied by X-ray photoelectron spectroscopy using monochromatized Al Kα radiation. These films are composed of metastable bcc, fcc and amorphous phases depending on the alloy composition. Their valence band spectra consist of well-resolved peaks representative of Fe-, Cu- and Ag-derived d bands in the respective alloy systems, whose spectral features are similar to those of Ni-Cu and Pd–Ag alloys reported by Hüfner et al. The spectral component of the Fe-derived d band near the Fermi level tends to shrink rapidly in Cu- and Ag-rich fcc alloys. This feature is discussed in relation to the variation of the Curie temperature with the Cu or Ag concentration in these alloys. The core-level spectra of Fe 2 p , Cu 2 p and Ag 3 d states reveal that charge transfer among constituent elements is not appreciable. The effects of thermal annealing and the attendant phase separation upon these XPS spectra are also studied.