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MA: Magnetismus
MA 9: Magnetic Imaging
MA 9.5: Talk
Monday, March 27, 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)