Regensburg 2010 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 41: Poster Session I (Semiconductor Substrates: Epitaxy and growth; Semiconductor Substrates: Adsorbtion; Semiconductor Substrates: Solid-liquid interfaces; Semiconductor Substrates: Clean surfaces; Oxides and insulators: Epitaxy and growth; Oxides and insulators: Adsorption; Oxides and insulators: Clean surfaces; Organic, polymeric and biomolecular films - also with adsorbates; Organic electronics and photovoltaics, Surface chemical reactions; Heterogeneous catalysis; Phase transitions; Particles and clusters; Surface dynamics; Surface or interface magnetism; Electron and spin dynamics; Spin-Orbit Interaction at Surfaces; Electronic structure; Nanotribology; Solid/liquid interfaces; Graphene; Others)

O 41.92: Poster

Dienstag, 23. März 2010, 18:30–21:00, Poster B1

Comparison of topography and electronic structure of Gd/W(110) and Gd/Y(0001) — •Karen Zumbrägel, Henry Wortelen, Anke B. Schmidt, and Markus Donath — Physikalisches Insitut, Westfälische Wilhelms-Universität Münster, Germany

In Gd the 4f electrons are the main carriers of the magnetic moment. In contrast to the 3d ferromagnets Fe, Co and Ni, whose ferromagnetic coupling occurs via direct exchange, in Gd the polarisation of the 5d and 6s valence electrons mediates the ferromagnetic coupling (RKKY interaction). Hence the investigation of Gd is of fundamental relevance for understanding the nature of ferromagnetism.
The electronic structure of thin Gd films is studied as a function of film thickness, topography and substrate. We compare Gd films grown on W(110), the substrate prevalent in literature, with films grown on Y(0001). The high lattice mismatch between W and Gd of up to 15% leads to layer-island growth, while Gd grows layer-by-layer on the well fitting Y (mismatch 0.4%). Combined with varying annealing temperatures, films with different degrees of roughness and impurity could be investigated. For characterising the film quality we employ low energy electron diffraction, Auger electron spectroscopy and scanning tunnelling microscopy. Spin- and angle-resolved direct and inverse photoemission provide information about the spin-dependent electronic structure below and above the Fermi level. The surface state close to the Fermi energy is used as criterion for the quality of the preparation.