Regensburg 2007 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 15: Poster:ThinFilms(1-33),Transp.(34-49),ExchBias(50-56),
Spindynamics(57-70),Micro-nanostr.Mat.(71-82),
Particles/Clust.(83-88), Mag.Imag./Surface(89-96),
Spinelectronics(97-109), Theory/Micromag.(110-116),
Spinstruct/Phasetr.(117-128),Magn.Mat.(129-139),
Aniso.+Measuring(140-145), MolMag.(146-152),
MSMA(153-156)

MA 15.22: Poster

Dienstag, 27. März 2007, 15:00–19:00, Poster A

Magnetic anisotropy in Fe_1−xCo_x films on Pd(001), Pd/Cu(001) and Pd/GaAs(001) — •Xiuli Fu, Feng Luo, Jochen Barthel, Marek Przybylski, and Jurgen Kirschner — Max-Planck-Institut fur Mikrostrukturphysik, Halle, Germany

Tetragonally distorted Fe_1−xCo_x alloy films were grown on Pd(001) at room temperature (RT) by molecular beam epitaxy using thermal evaporation from two effusion cells. First-principles calculations for such films predict a high uniaxial magnetic anisotropy energy for specific values of the lattice distortion and the alloy composition x. Magneto-optical Kerr effect measurements have shown that the magnetic anisotropy depends strongly on temperature. For example, the out-of-plane easy axis of magnetization is observed for Fe_0.5Co_0.5 films up to the thickness of 14 ML at 60 K, whereas at RT the films are magnetized in-plane. A thermal expansion and related changes of the tetragonal distortion are supposed to be responsible for this effect. The explanation is verified by a comparison to the Fe_1−xCo_x alloy films grown on a Pd buffer layer on Cu(001) and GaAs(001). Such systems are characterized by different thermal expansion coefficients. Additionally, the tetragonal distortion can be controlled by the thickness of the Pd buffer layer. It decreases for the growth on Cu(001) and increases for the growth on GaAs(001) with decreasing Pd thickness.