Berlin 2018 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 58: Surface magnetism II
MA 58.1: Vortrag
Freitag, 16. März 2018, 09:30–09:45, EB 202
Magnetic structure of MnO2 and FeO2 chains on Ir(100) investigated by spin-polarized STM — •Martin Schmitt, Matthias Vogt, Ryan Cotsakis, Jeannette Kemmer, and Matthias Bode — Physikalisches Institut, Experimentelle Physik II, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
Low-dimensional systems are known to behave different from bulk properties.
In particular, for monatomic 3d transition metal chains
unconventional magnetic ground states have been theoretically predicted [1].
Recently, a new self-organized growth method of transition metal oxide (TMO) chains
with a structural (3×1) unit cell on Ir(100) has been reported [2].
DFT calculations predict a rather strong antiferromagnetic (AFM) coupling
along MnO2 and FeO2 chains, but only a weak AFM interaction across the chains.
We performed low-temperature spin-polarized scanning tunneling microscopy (SP-STM)
to unravel the spin structure of various TMO chains on Ir(100) at 5 K.
Our results confirm an AFM coupling for MnO2 and FeO2 along the stripes.
Surprisingly, we also find pronounced magnetic order in between adjacent chains.
Whereas a ferromagnetic (FM) inter-stripe coupling leading to a (3×2) magnetic unit cell is found for FeO2,
MnO2 chains show a complicated non-collinear ground state with a (9×2) magnetic unit cell.
Potential ordering mechanisms which may lead to this spin structure will be discussed.
M. Tanveer et al., Phys. Rev. B 94, 094403 (2016);
further references therein.
P. Ferstl et al., Phys. Rev. Lett. 117, 046101 (2016).