Berlin 2012 – scientific programme

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MA: Fachverband Magnetismus

MA 37: Joint Session "Surface Magnetism II" (jointly with O)

MA 37.1: Talk

Thursday, March 29, 2012, 09:30–09:45, EB 301

Magnetism of Cobalt Nanoclusters on Graphene on Ir(111) — •Stefan Schumacher¹, Chi Vo-Van², Johann Coraux², Violetta Sessi³, Olivier Fruchart², Nick B. Brookes³, Philippe Ohresser⁴, and Thomas Michely¹ — ¹II. Physikalisches Institut, Universität zu Köln, D-50937 Köln — ²Institut Néel, CNRS et Université Joseph Fourier, F-38042 Grenoble — ³European Synchrotron Radiation Facility, F-38043 Grenoble — ⁴Synchrotron SOLEIL, F-91192 Gif-sur-Yvette

On the moiré pattern of graphene on Ir(111) a variety of highly perfect cluster superlattices with narrow size distribution can be grown. The magnetic properties of Co clusters comprising from 26 to 2700 atoms, densely self-organized on the graphene/Ir(111) moiré as well as in more sparse arrangements, were studied in situ by means of scanning tunneling microscopy (STM) and X-ray magnetic circular dichroism (XMCD). Surprisingly the small clusters show almost no magnetic anisotropy. We find indication for a magnetic coupling between the clusters. Experiments have to be performed carefully as the clusters get readily damaged by soft X-rays.