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MA: Magnetismus

MA 9: Magnetic Imaging

MA 9.5: Vortrag

Montag, 27. März 2006, 16:00–16:15, HSZ 401

Spin structure of surface atoms of equatomic NiMn films on Cu(001) — •Chunlei Gao, Hagen Wald, Wulf Wulfhekel, Aimo Winkelman, Marek Przybylski, and Jürgen Kirschner — Max Planck Institute of Microstructure Physics, Halle, Germany

Equiatomic MnNi crystallizes in the face centered tetragonal CuAu-I-structure with Mn and Ni atoms occupying alternating planes perpendicular to the tetragonal axis. The magnetic moments of nearest-neighbor manganese atoms (in planes normal to the tetragonal axis) are antiparallel to each other and the moments of nickel almost vanish[1]. In this contribution, Mn₅₀Ni₅₀ thin films with the thickness between 8 to 20 monolayers were epitaxially grown on Cu(001) by co-evaporation. A (√2× √2)R45^∘ superstructure was observed with low energy electron diffraction (LEED) which was attributed to the chemical order of Mn₅₀Ni₅₀ thin films. The surface was investigated by scanning tunneling microscopy (STM) and spin polarized STM with in-plane sensitivity[2]. Mn and Ni planes were found perpendicular to the surface resulting in two structural domains. An additional p(2×2) superstructure was observed in both topography and spin. A possible noncollinear antiferromagnetic arrangement of the surface moments is proposed to explain the experimental results.

[1] J. S. Kasper and J. S. Kouvel, J. Phys. Chem. Solids. 11, 213 (1959)

[2] U. Schlickum, W. Wulfhekel, and J. Kirschner, Appl. Phys. Lett. 83, 2016 (2003)