X-ray photoelectron spectroscopy study of MBE-grown Gd/EuTe multilayers

Photoelectron spectroscopy has been used to study the Gd/EuTe multilayers structure covered with a thin (100 Å) Al film. The study of the main core level and valence band photoemission spectra has shown no interaction between Gd and EuTe layers. Gadolinium was in pure metallic state and the ions of Eu were found divalent in the Gd/EuTe multilayers structure. The europium ions spectra analysis indicates that Ar+ ion sputtering of the sample surface leads to a deviation from stoichiometry in the near surface region of the EuTe layers and to the appearance of Eu3+ species in uppermost layers of the Gd/EuTe multilayers structure. The long-time exposure to the XPS ambient gases has been characterized from the analysis of europium 3d core level spectra.