Magnetism of FePt Surface Alloys

J. Honolka1, T.Y. Lee1, K. Kuhnke1, A. Enders2, R. Skomski2, S. Bornemann3, S. Mankovsky3, J. Minar3, J. Staunton4, H. Ebert3, M. Hessler5, K. Fauth6, G. Schütz5, A. Buchsbaum7, M. Schmid7, P. Varga7, K. Kern1

1 Max-Planck-Institut für Festkörperforschung, 70569 Stuttgart, Germany
2 Dept. of Physics and Astronomy and MCMN, University of Nebraska, Lincoln, NE 68588, USA
3 Department Chemie und Biochemie, Ludwig-Maximilians-Universität München, 81377 München, Germany
4 Department of Physics, University of Warwick, Coventry CV47AL, United Kingdom
5 Max-Planck-Institut für Metallforschung, 70569 Stuttgart, Germany
6 Physikalisches Institut, Universität Würzburg, 97074 Würzburg, Germany
7 Institut für Allgemeine Physik, Technische Universität Wien, 1040 Wien, Austria

Phys. Rev. Lett. 102 (2009) 067207

The complex correlation of structure and magnetism in highly coercive monoatomic FePt surface alloys is studied using scanning tunneling microscopy, X-ray magnetic circular dichroism and ab-initio theory. Depending on the specific lateral atomic coordination of Fe either hard magnetic properties comparable to that of bulk FePt or complex non-collinear magnetism due to Dzyaloshinski-Moriya interactions are observed. Our calculations confirm the subtle dependence of the magnetic anisotropy and spin alignment on the local coordination and suggest that 3D stacking of Fe and Pt layers in bulk L10 magnets is not essential to achieve high anisotropy values.

Corresponding author: J. Honolka. Reprints also available from M. Schmid (schmid< encoded email address >).

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