Regensburg 2016 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 28: Surface Magnetism I (jointly with O)

MA 28.4: Vortrag

Mittwoch, 9. März 2016, 10:15–10:30, H31

Non-collinear magnetic order at room temperature — •Aurore Finco, Pin-Jui Hsu, Thomas Eelbo, Niklas Romming, André Kubetzka, Kirsten von Bergmann, and Roland Wiesendanger — Department of Physics, University of Hamburg, Jungiusstrasse 11, 20355 Hamburg, Germany

Non-collinear magnetic structures like skyrmions are very promising for spintronics applications. They can be stabilized in ultrathin films by the Dzyaloshinskii-Moriya interaction induced by the interface between a heavy element substrate and the magnetic layer. Spin-polarized scanning tunneling microscopy is a very powerful tool to investigate these complex spin structures down to the atomic scale. Using this technique, it was shown that the magnetic structure of the 1st layer Fe on Ir(111) is a nanoskyrmion lattice below 30 K [1]. Going to higher Fe coverage, an increased thermal stability can be expected.

At low temperature, spin spirals guided by reconstruction lines (due to lattice mismatch between Fe and Ir) are visible on both the 2nd [2] and the 3rd layer Fe on Ir(111) with periodicities of about 1.5-2 nm and 4-9 nm respectively. While the 2nd layer does not respond to a magnetic field, the 3rd layer spirals transform into single distorted skyrmions under an out-of-plane field of about 2 T. In the absence of a field, the measurement temperature was raised up to room temperature. On the 2nd layer, the cycloidal spin spirals disappear above 150 K whereas the 3rd and 4th layers exhibit a non-collinear magnetic structure at room temperature with a periodicity of 30 to 60 nm.

[1] Sonntag et al, PRL, 113 077202 ; [2] Hsu et al, PRL, in press