Regensburg 2016 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 28: Surface Magnetism I (jointly with O)

MA 28.5: Vortrag

Mittwoch, 9. März 2016, 10:45–11:00, H31

Evidence for non-collinear surface magnetic order of Gd(0001) by spin-polarized scanning tunneling microscopy — •Matthias Vogt, Martin Schmitt, Jeannette Kemmer, and Matthias Bode — Physikalisches Institut, Experimentelle Physik II, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany

We present spin-polarized scanning tunneling microscopy measurements of Gd(0001) films grown on W(110). In agreement with previous publications [1] we observed an exchange-split surface state with an occupied majority and an empty minority part. For film thicknesses between 6 and 240 atomic layers maps of the differential conductivity dI/dU measured with magnetically coated probe tips show a magnetic structure which is dominated by six contrast levels. They represent magnetic domains which are most likely the consequence of the hexagonal Gd surface structure, which results in six equivalent easy axis, similar to earlier reports on Dy(0001) films [2]. Additionally, close inspection reveals weak intensity modulations within the domains with a periodicity of about 2 nm. Their amplitude is strongly bias dependent and varies for different domains. The fact that these modulations are absent if measured with non-magnetic tips indicates their magnetic origin. We will present different potential non-collinear spin configurations and discuss to what extend they agree with our experimental observations.

[1] M.  Bode et al., Phys. Rev. Lett. 81, 4256 (1998).
L.  Berbil-Bautista et al., Phys. Rev. B 76, 064411 (2007).