The structures of ultrathin Fe films on Cu͑100͒ prepared by pulsed laser deposition ͑PLD͒ and conventional thermal deposition ͑TD͒ are compared by means of low-energy electron diffraction ͑LEED͒. Below 5 ML coverage, PLD films exhibit up to four times higher integer-order LEED spot intensities, i.e., improved film quality, and show small but significant structural changes as compared to TD films. A quantitative tensor LEED analysis of the 4-ML PLD film reveals a similar 5ϫ1 superstructure to that found previously for TD films, but with an enhanced surface buckling and a flat Cu bulklike iron interface layer. The latter is attributed to the incorporation of Cu atoms in the Fe interface caused by sputter effects in PLD. Above 6-ML coverage, both deposition methods yield comparable LEED I(E) spectra, revealing similar surface structures. The proposed structural models allow a consistent interpretation of the strongly altered magnetic properties observed for PLD-grown iron films.
The relaxation of the first seven atomic layers of Cu͑117͒ was determined by quantitative low-energy electron diffraction ͑LEED͒. Intensity versus energy spectra, I(E), were measured for the primary beam at near-normal incidence to the ͑001͒ terraces. The data collected cover a cumulative energy range of 3200 eV. Computation of I(E) spectra was performed in the angular momentum representation by considering the surface as a single atomic slab. For the variation of parameters, tensor LEED was applied. The experimental spectra are well reproduced over the entire energy range even for regions of low intensity. The first four layer spacings relax in a way to smooth the surface corrugation, whereby the relative changes ⌬d/d 0 amount ͑from top͒ to Ϫ13%, Ϫ2.0%, Ϫ10%, and ϩ7%. This leads to a reduction of the vertical distance between step and corner atoms by 0.13 Å. Comparison with experimental results for Cu͑115͒ shows that this modification of the step shape is rather independent of the terrace width. Comparison to theoretical results exhibits, however, some discrepancies with respect to both the expansion/contraction sequence and the amplitudes of the layer relaxations.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.