Regensburg 2004 – wissenschaftliches Programm

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O: Oberflächenphysik

O 14: Postersitzung (Adsorption an Oberflächen, Epitaxie und Wachstum, Organische Dünnschichten, Oxide und Isolatoren, Phasenübergänge, Rastersondentechniken, Struktur und Dynamik reiner Oberflächen)

O 14.43: Poster

Montag, 8. März 2004, 18:00–21:00, Bereich C

Growth and morphology of Co films on Pd(111) — •M. Przybylski, M. Wasniowska, W. Wulfhekel, and J. Kirschner — Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, 06120 Halle

Ultrathin Co films were grown on an atomically clean and flat surfaces of Pd(111). Scanning Tunneling Microscopy (STM) shows that at 300K the growth starts by a formation of double-layer patches of a hexagonal shape. The Moiré pattern due to the 8.7% lattice mismatch of Co and Pd was clearly seen. At 170K, mobility of Co atoms is strongly reduced resulting in a more dense packing of the double-layer patches. At the coverage of ≈2ML of Co grown at 170K almost the whole surface (95%) is covered with the double-layer patches, in comparison to only 70% if the growth proceeds at 300K. In the latter case higher layers nucleate when the patches approach the size of 50nm. After annealing at 420K, the STM image shows drastically changed morphology of the film. A monolayer of Co appears which is continuous and covers 98% of the sample area. This is associated with changes of the LEED pattern: after annealing only single spots of hexagonal symmetry, typical for Pd(111), are seen with no superstructure spots, which were clearly visible before annealing.