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O: Fachverband Oberflächenphysik
O 61: Nanostructures at Surfaces III
O 61.10: Vortrag
Mittwoch, 2. April 2014, 18:15–18:30, WIL B321
Magnetic anisotropy of monolayer Co/Ir(111) and graphene/Co/Ir(111) — •Alexander B. Shick1, Frantisek Maca1, and Alexander I. Lichtenstein2 — 1Institute of Physics, Academy of Sciences of the Czech Republic, Prague, Czech Republic — 2Institute of Theoretical Physics, University of Hamburg, Hamburg, Germany
The positive magnetic anisotropy in cobalt-intercalated graphene on Ir(111) attracts interest due to spintronics applications [1]. The magnetism, and the magnetic anisotropy energy (MAE) of monolayer Co/Ir(111) and graphene/Co/Ir(111) are studied making use of the first-principles FP-LAPW, and the magnetic torque methods, including the element-specific contributions to the MAE. We found reasonable agreement for the MAE with previous KKR-ASA calculations of monolayer Co on Ir(111) for unrelaxed structure [2]. The structure relaxation provides a substantial positive MAE enhancement, and the MAE of 0.45 meV per Co is consistent with experiment [3]. The magnetic moments and the MAE are strongly affected by presence of graphene. For the placement with one of the C atoms on the top of Co ("top" position) the MAE becomes negative. For different arrangement, with graphene in the hexagonal hollow positions over the monolayer Co ("hex"), the effect of graphene is weaker, and the MAE stays positive. The role of Coulomb correlations beyond DFT will be discussed. [1] N. Rougemaille et al., Appl. Phys. Lett., 101, 142403 (2012); [2] S. Bornemann et al., Phys. Rev B86, 104436 (2012); [3] J.E. Bickel et al., Phys. Rev B84, 054454 (2011).