Structure and growth of ultrathin iron films on [formula omitted

Abstract

The structure and growth of ultrathin iron films on pseudomorphic Ni Cu(100) was investigated by low and medium energy electron diffraction (LEED and MEED), respectively. A similar sequence of superstructures as previously found for Fe Cu(100) was observed. With growing film thickness a (4 × 1)-, a (2 × 1)- and a pseudo “(3 × 1)”- phase are found. Our full-dynamical LEED analysis of the (2 × 1) phase reveals a structure that very closely resembles the unusual (2 × 1)-phase on Fe Cu(100) . We find a considerable expansion to 1.880 Å for the first interlayer spacing, while deeper layers have an interlayer spacing of 1.78 Å, characteristic for cubic fcc iron. This implies that magnetic live surface layers should also exist for fcc iron on Ni Cu(100) . Small deviations in the structure and growth of Fe on Ni Cu(100) as compared with Fe on Cu(100) can be attributed to the roughness of the underlying nickel films.