Polarized neutron reflectometry study of ultrathin Fe layers on V(110) and V(100)

The absolute magnetization of ultrathin Fe layers on V(1 1 0) and V(1 0 0) was determined by polarized neutron reflectivity. The investigations were performed with Fe layer thicknesses between 6 and 12 Angstrom. All Fe films were covered with a Cr layer of about 300 Angstrom thickness. The films were prepared in ultrahigh vacuum by molecular beam epitaxy. The film structure was investigated by low energy electron diffraction (LEED) and Auger electron spectroscopy (AES). The LEED patterns reveal that the Fe and Cr films grow epitaxially on both substrate orientations and the AES data are in accordance with a layer by layer growth model. The measuring temperature was varied between 2 and 300 K. We find a nearly temperature-independent reduction of the magnetization compared to the Fe bulk value. The reduction increases with decreasing Fe film thickness. (C) 1998 Elsevier Science B.V. All rights reserved.