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MA: Fachverband Magnetismus

MA 2: Bio- and Molecular Magnetism

MA 2.8: Vortrag

Montag, 22. März 2010, 12:30–12:45, H10

Magnetic coupling between Fe phthalocyanine molecules and ferromagnets — •Claudia Weis, Bernhard Krumme, Frank Stromberg, Anne Warland, Carolin Antoniak, Werner Keune, and Heiko Wende — Fakultät für Physik and CeNIDE, Universiät Duisburg-Essen

On the road towards molecular spintronic devices magnetic organic molecules on ferromagnetic surfaces play an important role. Going beyond earlier investigations on Fe porphyrin (FeOEP) molecules [1-2] the present work aims to study the influence of changes in the ligand field on the magnetic coupling. From Mössbauer spectra of bulk-like samples, it is obvious that a considerable difference occurs between Fe phthalocyanine (FePc) and FeOEP. We investigate sub-monolayer coverages of magnetic FePc molecules on ultrathin ferromagnetic films of Ni and Co on Cu(100) by X-ray absorption spectroscopy (XAS) and X-ray magnetic circular dichroism (XMCD). We find that also the FePc molecules couple to ferromagnets similar to the FeOEP molecules [1-2]. The magnetic coupling between the molecules and the magnetic substrate turns from ferromagnetic to antiferromagnetic if an interlayer of oxygen is introduced by oxygen surfactant-assisted growth of the ferromagnetic film. Similarities and differences in the fine structure of the spectra will be discussed in detail.

[1] H. Wende et al., Nature Materials 6, 516 (2007).

[2] M. Bernien et al., Phys. Rev. Lett. 102, 047202 (2009).

– Supported by DFG (Sfb 491) and BMBF (05 ES3XBA/5).