Regensburg 2007 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 13: Spinstructures and magnetic Phase Transitions
MA 13.5: Vortrag
Dienstag, 27. März 2007, 11:15–11:30, H5
Discovery of a Cycloidal Spin Spiral in a Two-Dimensional Antiferromagnet — •Matthias Bode1, Marcus Heide2, Kirsten von Bergmann1, Paolo Ferriani1, Stefan Heinze1, Gustav Bihlmayer2, Andre Kubetzka1, Oswald Pietzsch1, Stefan Blügel2, and Roland Wiesendanger1 — 1Institut für Angewandte Physik, Universität Hamburg, Jungiusstr. 11, 20355 Hamburg — 2Institut für Festkörperforschung, Forschungszentrum Jülich, 52425 Jülich
Spin structures observed in nanomagnets are commonly explained on the basis of the Heisenberg exchange interaction and the magnetic anisotropy. In a two-dimensional antiferromagnetic metal film with the thickness of a single-atomic Mn layer on W(110) we observe a spin spiral in real space by means of spin-polarized scanning tunneling microscopy at 13 K. First-principles calculations identify the spiral as cycloidal spin order with specific chirality and prove that it is caused by the Dzyaloshinskii-Moriya (DM) interaction arising from the lack of structural inversion symmetry inherent to all surfaces and interfaces. We establish the significance of the DM interaction for magnets in reduced dimensions, whose strength is sufficient to destabilize the so far anticipated collinear magnetic structures. The chirality in nanomagnets can contribute to interesting phenomena in spintronics.