Comparative study of magnetism and interface composition in Fe/GaAs(100) and Fe/InAs(100)

Thin layers of Fe are deposited at 100 degrees C on GaAs(1 0 0) and InAs(1 0 0) substrates by molecular beam epitaxy. These structures are characterized by photoelectron spectroscopy (PES), in order to derive their chemical composition and interface reactivity, and by X-ray magnetic circular dichroism (XMCD) recorded at room temperature in remanence mode, in order to derive the atomic magnetic moment of Fe. As previously reported, Fe/GaAs(1 0 0) exhibits a strong and complicated interface reactivity, with considerable intermixing of Fe with Ga and As. Unlike the above structure, Fe/InAs(1 0 0) exhibits a much lower interface reactivity, whereas the Fe magnetic moment increase is much more pronounced as function of Fe thickness. The total atomic ferromagnetic moment reaches at room temperature 2.0 Bohr magnetons by about I nm Fe effective thickness, which is almost the Fe bcc bulk value (2.2 Bohr magnetons). The novelty of the present study is a direct comparison of the two interfaces prepared and measured in the same experimental arrangements. (c) 2006 Elsevier B.V. All rights reserved.