Dresden 2020 – wissenschaftliches Programm
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SYES 2.1: Hauptvortrag
Donnerstag, 19. März 2020, 15:00–15:30, HSZ 01
Interactions in assemblies of surface-mounted magnetic molecules — •Wolfgang Kuch — Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
Organic magnetic molecules have great potential for defining the spin of electrons, logic operations, or data storage in future miniaturized electronic devices. For that, the molecules need to be immobilized and contacted, which involves adsorption on solid surfaces. Understanding and controlling the interactions of adsorbed metal–organic magnetic molecules with each other and the environment is thus an important step towards a surface-mounted molecular spin electronics.
X-ray absorption spectroscopy (XAS) is particularly well suited for the experimental investigation of such interactions. The elemental specificity of X-ray magnetic circular dichroism allows to explore the magnetic interaction between ferromagnetic substrates and adsorbed molecules. It is found to persist even across a layer of graphene and could be used, for example, to stabilize the molecule’s magnetic moments against thermal fluctuations. Field-dependent measurements yield insight into the magnetic interaction between neighboring molecules in one- or two-dimensional molecular surface assemblies. The decisive role of the substrate on the magnetic properties of adsorbed molecules is emphasized by the change in spin state caused by a relatively subtle modification of the substrate such as a different crystallographic surface orientation. Finally, directly probing the d occupation by XAS, cooperativity in the thermally induced spin-state switching between adsorbed spin-crossover molecules is identified.