Berlin 2018 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 33: Biomedical and molecular magnetism
MA 33.7: Vortrag
Mittwoch, 14. März 2018, 16:45–17:00, H 1012
Effect of electron doping on Fe4 single molecule magnets at surfaces — •Fabian Paschke, Vivien Enenkel, Philipp Erler, Luca Gragnaniello, and Mikhail Fonin — Fachbereich Physik, Universität Konstanz, 78457 Konstanz, Germany
The controlled deposition, characterization and manipulation of single molecule magnets (SMMs) on surfaces is one of the crucial topics for their use as units in future electronic and spintronic applications. We recently showed that by using the electrospray deposition of Fe4H SMMs self-organized arrays on insulating h-BN/Rh(111)1 and graphene/Ir(111)2 surfaces can be prepared. On graphene/Ir(111) the robustness of the Fe4 complex is demonstrated as the magnetic anisotropy retains its bulk value despite a non-negligible electronic interaction with the substrate2. Here we use scanning tunneling microscopy and spectroscopy as well as x-ray magnetic circular dichroism (XMCD) to investigate the effect of alkali metal (Li) doping on the charge state and magnetic anisotropy of Fe4H on graphene/Ir(111) and Au(111). Doped molecules show emerging electronic states in the conduction gap and shifted energy positions of molecular orbitals. XMCD measurements indicate substantial changes in the multiplet structure at the Fe L-edge, presumably caused by partial reduction of Fe3+ to Fe2+ in the inorganic core. The magnetic anisotropy of the molecules is shown to be suppressed upon doping with alkali atoms.
[1] P. Erler et al., Nano Lett. 15, 4546 (2015). [2] L. Gragnaniello et al., Nano Lett., 2017, in press.