Dresden 2006 – scientific programme

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MA: Magnetismus

MA 4: Magnetic Materials I

MA 4.10: Talk

Monday, March 27, 2006, 12:30–12:45, HSZ 401

First-principles investigation of Co wires at Pt(111) step-edges — •Gustav Bihlmayer¹, Stéphanie Baud², Christophe Ramseyer², and Stefan Blügel¹ — ¹Forschungszentrum Jülich, Institut für Festkörperforschung, Jülich, Germany — ²Laboratoire de physique moléculaire, UMR CNRS 6624, Besançon, France

We investigate Co wires of different width deposited on step-edges of Pt(111), simulated by a Pt(664) surface. The calculations were preformed within the framework of the density functional theory using the FLAPW method. An adsorbed Co chain showed a magnetic anisotropy energy (MAE) and easy axis in good agreement with experimental data [1]. Inclusion of relaxations turned the easy axis even more in the direction of the upper terrace and quenched the orbital moments and their anisotropy. While this seems unfavorably in comparison to experiment, we argue – based on a decomposition of the contribution to the MAE of the different atoms (Pt or Co) – that relaxations might be an essential part of the calculations including orbital polarizations. We investigated also the evolution of the easy axes and the MAE as function of the number of Co chains deposited on the stepped surface. The results nicely compare to those obtained experimentally [2]. We present a simple model to account for the experimentally observed oscillations of the easy axis.

[1] P.Gambardella et al. Nature 416, p.301 (2002)

[2] P.Gambardella et al. Phys. Rev. Lett. 93 077203 (2004)