In-plane fourfold and uniaxial magnetic anisotropies were studied in Fe films epitaxially grown on vicinal Ag(001) and Au(001) surfaces, which were prepared by molecular beam epitaxy on miscut GaAs(001) substrates. The effective fourfold and uniaxial anisotropy constants, K1eff and Kueff, which are determined from magnetisation curves measured with the magneto-optic Kerr effect, are linear functions of the inverse Fe layer thickness. The fourfold anisotropy shows a rotation of the easy and hard axes by 45° below a critical thickness of 6–7 ML. The uniaxial term is mainly an interface contribution. We find that the orientation of the uniaxial easy axis depends on the Fe thickness. In thinner films (tFe⩽20 ML) it is oriented perpendicular to the step edges, i.e., parallel to Fe[100]. This excludes shape anisotropy as the main mechanism. Above a critical thickness the uniaxial easy axis is aligned parallel to the step edges, i.e., along Fe[010]. This step-induced uniaxial anisotropy may be due to modified electronic states and to strain from the large vertical misfit at the steps.

An experiment to probe spin-polarized currents in the quantum Hall regime is suggested that takes advantage of the large Zeeman-splitting in the paramagnetic diluted magnetic semiconductor zinc manganese selenide ͑Zn 1−x Mn x Se͒. In the proposed experiment spin-polarized electrons are injected by ZnMnSe-contacts into a gallium arsenide (GaAs) two-dimensional electron gas (2DEG) arranged in a Hall bar geometry. We calculated the resulting Hall resistance for this experimental setup within the framework of the Landauer-Büttiker formalism. These calculations predict for 100% spin injection through the ZnMnSe-contacts a Hall resistance twice as high as in the case of no spin-polarized injection of charge carriers into a 2DEG for filling factor = 2.We also investigated the influence of the equilibration of the spin-polarized electrons within the 2DEG on the Hall resistance. In addition, in our model we expect no coupling between the contact and the 2DEG for odd filling factors of the 2DEG for 100% spin injection, because of the opposite sign of the g-factors of ZnMnSe and GaAs.