Photoemission and EDXRD study of annealed Fe/ Al multilayers using synchrotron radiation

Full text; Multilayer structures based on the intermetallic phases of the Fe-Al systems are found to be interesting candidates for possible applications in magnetic recording due to their soft magnetic properties with high magnetization and good control over Fe magnetic domain. However, all these properties are basically dictated by the interactions between the Al-sp and TM-d bands and any subtle changes in the p-d hybridization brought by a variation in Al concentration affect the chemical bonding and phase stability of intermetallic alloy. Therefore, in order to gain the basic understanding about the electronic properties changes at the interface due to thermal annealing and variation in concentration, compositionally modulated electron beam evaporated Fe/Al multilayer samples (MLS) with an average composition of Fe0.70Al10.30 (MLS-A) and Fe0.50Al0.50 (MLS-B) were studied using photoelectron spectroscopy (PES). The core level study show a gradual change in the nature of the electronic bonding at the interface as a result of annealing. In particular, the MLS annealed at 400 degree Celsius clearly show shifts in the binding energy position of Fe core line towards higher energy and Al core line towards lower energy side as compared to as-deposited sample, suggesting the formation of FeAl alloy phase at the interface. The corresponding valence band spectra show appreciable changes in the Fe-3d as well as Al-3s density of states due to strong hybridization of sp-d states at the Fermi level as a result of charge transfer and also provide strong evidence for FeAl alloy formation. (author)