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MA: Magnetismus

MA 4: Oberfl
ächenmagnetismus

MA 4.1: Vortrag

Montag, 8. März 2004, 10:15–10:30, H22

Structure and magnetism in the MnCu/Cu(001)-c(2x2) and p2gg-(4x2) surface alloys — •Popescu R.1, Meyerheim H.L.1, Sander D.1, Ernst A.1, Robach O.2, Ferrer S.2, Kirschner J.1, and Bruno P.11MPI für Mikrostrukturphysik, Weinberg 2, 06120 Halle, Germany — 2ESRF, BP 220, F-38043 Grenoble, France

The two-dimensional magnetic alloy phases formed by deposition of Mn on Cu(001) in the coverage range between about 0.5 and 1 monolayer (ML, 1ML=1.53×1015 atoms/cm2) were investigated by surface x-ray diffraction (SXRD) and calculations based on the full potential layered Korringa-Kohn-Rostoker-method implemented within the DFT. While for the c(2x2) phase formed at 0.5 ML the basic two dimensional alloy structure model with Mn-atoms replacing every other Cu surface atom is confirmed (Mn at 0.20± 0.05 Åabove the Cu-layer), in detail an accurate fit to the 228 reflections (unweighted R≈ 0.07) is only obtained by taking into account 0.5 ML of Cu atoms above the alloy layer and a fraction of 20 percent anti-phase domains. The calculations show, that the magnetic moment of the Mn-atoms is in the 3.8 µB-range independent of the presence or absence of the Cu-adlayer. The p2gg-(4x2) superstructure is also characterized by a single MnxCu1−x alloy layer, where the Mn-concentration (x) is in the range of about 0.8 and the corrugation in the 0.4Årange. The implications of the increased Mn-concentration (x) on the magnetic moment is discussed.

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DPG-Physik > DPG-Verhandlungen > 2004 > Regensburg