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O: Fachverband Oberflächenphysik
O 50: [MA] Joint Session "Surface Magnetism I" (jointly with O)
O 50.4: Vortrag
Mittwoch, 28. März 2012, 16:45–17:00, BH 243
Micromagnetic simulations of the spin spiral state in bi-atomic Fe chains on Ir(001) — •Matthias Menzel1, Yuriy Mokrousov2, Robert Wieser1, Jessica Bickel1, Elena Vedmedenko1, Stefan Blügel2, Stefan Heinze3, Kirsten von Bergmann1, André Kubetzka1, and Roland Wiesendanger1 — 1Institut für Angewandte Physik, Universität Hamburg — 2Institut für Festkörperforschung, Forschungszentrum Jülich — 3Institut für Theoretische Physik und Astrophysik, Universität Kiel
Recent spin-polarized scanning tunneling microscopy (SP-STM) measurements in combination with ab initio calculations reveal a 120∘ spin spiral ground state in bi-atomic Fe chains on (5×1)-Ir(001) [1]. Monte-Carlo simulations have shown that thermally induced switching of this magnetic state leads to a time-averaged signal in the SP-STM measurements.
We performed time-resolved and temperature dependent simulations using the Object Oriented MicroMagnetic Framework (OOMMF) [2] to investigate the thermal fluctuations and the stabilization mechanism. Due to their reduced coordination the chain’s end atoms are more susceptible to an external magnetic field and the magnetocrystalline anisotropy and play a crucial role for the observability of the spin spiral. The three atom periodicity of the spin spiral leads to three symmetry classes for chains of different lengths, and we show how this affects the stability of the spin spiral.
[1] M. Menzel et al., submitted.
[2] http://math.nist.gov/oommf/