Berlin 2018 – scientific programme
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O: Fachverband Oberflächenphysik
O 26: Organic-inorganic hybrid systems and organic films III
O 26.2: Talk
Tuesday, March 13, 2018, 10:45–11:00, MA 042
Light-Induced Spin Crossover in an Fe(II) Low-Spin Complex Enabled by Surface Adsorption — •Sebastian Rohlf1, Manuel Gruber1, Benedikt Flöser2, Jan Grunwald2, Simon Jarausch1, Florian Diekmann1, Matthias Kalläne1, Torben Jasper-Tönnies1, Richard Berndt1, Felix Tuczek1, and Kai Rossnagel1 — 1Institut für Experimentelle und Angewandte Physik, Universität Kiel, 24098 Kiel, Germany — 2Institut für Anorganische Chemie, Universität Kiel, 24098 Kiel, Germany
The controlled spin-state manipulation of Fe(II) coordination complexes by external stimuli is associated with pronounced changes in the electronic, magnetic, and structural properties and may be implemented in future spintronic devices. To preserve the functionality of spin-crossover (SCO) complexes in device-like environments, where the molecules are typically fragile, such as in direct contact to a metallic surface, their sterical stability needs to be enhanced. However, this generally leads to a decrease of the transition temperature below which bi-directional spin switching is possible. Here, we present a near edge X-ray absorption fine structure (NEXAFS) spectroscopy study of the stabilized SCO derivative Fe(PyPyr(CF3)2)2(phen) adsorbed on metallic surfaces. SQUID measurements showed that the high-spin state appears to be fully suppressed in the bulk complex. In contrast, our NEXAFS results indicate that in thin films the SCO functionality is activated in the vicinity of the surface. At low temperatures and during laser light irradiation, the studied complex exhibits an almost complete low-spin to high-spin state transition, which has not been observed for other bulk low-spin complexes so far.