Berlin 2008 – wissenschaftliches Programm

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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 32.79: Poster

Freitag, 29. Februar 2008, 11:15–14:00, Poster E

Strong perpendicular anisotropy in Fe_1−xCo_x alloy films grown on Pd(001), Ir(001) and Rh(001) — •Fikret Yildiz, Feng Luo, Xiaodong Ma, Aimo Winkelmann, Marek Przybylski, and Jürgen Kirschner — Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, 06120 Halle, Germany

The orbital magnetic moment and magnetic anisotropy can be increased due to a tetragonal distortion in a system with bulk-like coordination. A model system is provided by Fe_1−xCo_x alloy films which are distorted due to their pseudomorphic growth on substrates of mismatching lattice constant like Pd, Ir or Rh. We have shown that the Fe_1−xCo_x alloy films of the composition around x=0.5 show a maximum perpendicular anisotropy when their cubic lattice is tetragonally distorted. With increasing film thickness the well ordered tetragonally distorted film fraction contributes less to the film volume causing the easy magnetization axis to be oriented in the film plane. Moreover, anisotropy depends strongly on the temperature. In the case of the Fe_1−xCo_x films grown on Pd(001) it results in the easy magnetization axis oriented out-of-plane only at low temperatures even for the 15 ML thick films. Only the films grown on Rh(001) show out-of-plane easy magnetization axis at room temperature in a broad thickness and composition range. This allows studying how the orbital moment and the magnetic anisotropy develop with increasing film thickness and with varying temperature of the sample.