Berlin 2008 – scientific programme

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MA: Fachverband Magnetismus

MA 32: Postersession II: Spinstruct./Phase Trans. (1-10); Spinelectronics (11-15); Thin Films (16 - 36); Particles/Clusters (37-45); Multiferroics (46-54); Spindynamics/Spin Torque (55 - 76); Post Deadlines (77-79)

MA 32.25: Poster

Friday, February 29, 2008, 11:15–14:00, Poster E

Magnetic properties of FeCo(110) on GaAs (110) cleaved edges — •Florian Nitsch, Björn Muermann, and Günther Bayreuther — Institut für Experimentelle und Angewandte Physik, Universität Regensburg, 93040 Regensburg, Germany

By cleaving a (001)-oriented GaAs wafer in UHV atomically flat and chemically clean GaAs(110) surfaces can be produced. To investigate a possible influence of surface roughness on the magnetic anisotropy of bcc Fe_1−xCo_x(110) films, layers grown by molecular beam epitaxy on such cleaved edges and on (110)-oriented GaAs wafers were investigated by alternating gradient magnetometry, magneto-optic Kerr effect and ferromagnetic resonance. Film thickness varied between 10 and 80 ML (monolayers) for compositions of x = 0.30 and x = 0.66. RHEED patterns showed a much lower step density of the cleaved edges compared to the GaAs(110) wafer surfaces prepared by UHV-annealing and Ar⁺ etching. The superposition of the cubic anisotropy (constant K₁) and a uniaxial anisotropy (K_U) is observed. Both anisotropy constants show a systematic thickness dependence resulting from the superposition of volume and interface contributions. A comparison with films grown on GaAs(001) indicates that in (110)-oriented films the uniaxial component is mainly of magneto-elastic origin. Both K₁ and K_U have about the same values for films grown on (110) wafers and on cleaved edges. It is concluded that for a thickness up to 80 ML the lattice relaxation due to the formation of misfit dislocations is not affected by the surface roughness of the substrates used in the present work.