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MA: Fachverband Magnetismus
MA 50: Surface magnetism III
MA 50.2: Talk
Thursday, March 17, 2011, 11:15–11:30, HSZ 103
Uniaxial anisotropy in Fe/GaAs(001): oriented bonds versus magneto-elastic interaction. — •Günther Bayreuther1,2, 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 KU 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 KU is expected to be of opposite sign for both materials, based on the respective values of B2. The observed identical sign of KU 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)