Study of electron beam evaporated compositionally modulated Fe/Al multilayers

This article presents temperature dependent magnetic and electronic properties of compositionally modulated electron beam evaporated Fe/Al multilayer samples (MLSs) with an average composition of Fe0.70Al0.30 (MLS-A) and Fe0.50Al0.50 (MLS-B). Structural studies show a large amount of intermixing, leading to alloying at the interfaces as a result of annealing. Both multilayer samples show soft ferromagnetic behavior at room temperature with an in-plane easy axis of magnetization. In both cases, coercivity as well as saturation field continuously increase and magnetization decreases with an increase in temperature. The Curie temperature (T-c) is found to decrease from similar to 561 degrees C for MLS-A to similar to 288 degrees C for MLS-B. These modifications can be attributed to the continuous change in electronic structure brought about by the strong hybridization of Fe 3d and Al 3sp states near Fermi level leading to the formation of different Fe-Al phases (Fe3Al in MLS-A) and (FeAl in MLS-B), as seen from valence band photoemission measurements. The formation of these phases is also supported by resistivity measurement. (C) 2008 American Vacuum Society.