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O: Fachverband Oberflächenphysik

O 63: [MA] Surface magnetism III

O 63.2: Vortrag

Donnerstag, 17. März 2011, 11:15–11:30, HSZ 103

Uniaxial anisotropy in Fe/GaAs(001): oriented bonds versus magneto-elastic interaction. — •Günther Bayreuther^1,2, Jörg Premper¹, Matthias Sperl², Dirk Sander¹, and Jürgen Kirschner¹ — ¹Max-Planck-Institut für Mikrostrukturphysik, Halle, Germany — ²Inst. für Experimentelle und Angewandte Physik, Universität Regensburg, Regensburg, Germany

Ultrathin Fe films epitaxially grown on GaAs(001), in addition to their thickness-dependent cubic anisotropy, show a pronounced in-plane uniaxial magnetic anisotropy with the easy axis along [110], controversially attributed either to oriented interface bonds or to a magneto-elastic interaction. In order to check the relevance of magneto-elastic contributions we performed MOKE and magneto-elastic stress measurements on MBE-grown Fe(001) and Fe₃₂Co₆₈(001) films on GaAs(001). The uniaxial anisotropy constant K_U has the same sign for Fe and Fe₃₂Co₆₈. The magneto-elastic coupling coefficients B₂ of the films were measured using a cantilever method [1] and resulted to be of opposite sign for Fe and Fe₃₂Co₆₈ films, respectively. As all the films are under compressive strain with a lattice misfit of -1.16 % for Fe and -0.41 % for Fe₃₂Co₆₈ the magneto-elastic anisotropy contribution to K_U is expected to be of opposite sign for both materials, based on the respective values of B₂. The observed identical sign of K_U in both cases means that a magneto-elastic interaction is not the main origin of the uniaxial magnetic anisotropy in ultrathin Fe(001) films on GaAs(001).

[1] D. Sander, Rep. Prog. Phys. 62, 809 (1999)