Regensburg 2016 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 17: Poster Session I
MA 17.31: Poster
Dienstag, 8. März 2016, 09:30–12:30, Poster B1
Correlation of the orbital moment with the local structure of CoOEP — •Nico Rothenbach1, Katharina Ollefs1, Andrei Rogalev2, Fabrice Wilhelm2, Francois Guillou2, and Heiko Wende1 — 1University of Duisburg-Essen, Faculty of Physics and CENIDE — 2European Synchrotron Radiation Facility (ESRF), ID12
We correlate the orbital magnetic moment of Co-octaethylporphyrin (CoOEP) molecules with its local geometric structure. This is achieved by means of combined XMCD and EXAFS study at the Co K-edge in the hard X-ray regime at the ESRF. The understanding of the magnetic interactions within molecular hybrid systems is essential for possible future applications e.g. for molecular spintronics [1]. Recently investigations of CoOEP on graphene/Ni(111) have shown a magnetic coupling via graphene to the Ni substrate. Sum rule analysis of XMCD spectra taken at the Cobalt L2,3-edge revealed a ratio of orbital to spin moment of ∼55% [2,3]. To study the orbital moment of CoOEP we measured the Co K-edge XMCD which is only sensitive to the orbital moment due to the absence of the SOC in the initial 1s state. We carried out measurements on two different samples: On the one hand we pressed the molecules to a pellet and on the other hand, we droped an mixture of the molecules dissolved in ethanol on a Si-Substrate. To correlate these results for the magnetic properties to the local structure we performed EXAFS measurements at the Co K-edge.
[1] H. Wende, Nature Materials 8, 165 (2009)
[2] C. F. Hermanns et al., Adv. Mater. 25, 3473 (2013)
[3] D. Klar et al., Phys. Rev. B 89, 144411 (2014)