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MA: Magnetismus
MA 19: Mikro- und nanostrukturierte Materialien I
MA 19.6: Vortrag
Mittwoch, 26. März 2003, 16:30–16:45, HSZ/405
Preparation of self assembled magnetic Fe nanostructure by organic prepatterning of Ag(976) — •H. L. Meyerheim1, X. Ma1, J. Barthel1, F. Porrati1, J. Kirschner1, S. Schmitt2, and E. Umbach2 — 1MPI f. Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany — 2II. Inst. f. Experimentalphysik, Univ. Würzburg, Am Hubland, D-97074 Würzburg
We report on the preparation of nano-structured Fe, which was deposited on PTCDA (perylene-tetracarboxylic-dianhydride) precovered Ag(976). Using STM it is shown that deposition of PTCDA on Ag(976) leads to step bunching resulting in a surface morphology characterized by (111) terraces separated by up to 1µ m long stripes of high index molecules covered facets [mostly with (753) surface orientation). Subsequently deposited Fe is found to adsorb preferentially up to a coverage of about 1 monolayer (1 ML=1.53×1015atoms/cm2) on the facets. MOKE- data indicate that the Fe-clusters (∅=3 nm, d=0.5 nm) are superparamagnetic (TB<70K), with a perpendicular easy axis. At higher Fe-coverage Fe islands are also observed on the (111)-terraces. At a coverage of 3.5 ML the easy axis is in-plane and shows a complicated azimuthal dependence, which on the basis of micromagnetic calculations can be interpreted by the superposition of different contributions (e.g. Fe on terraces and facets).