Berlin 2015 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 14: Surface Magnetism – Skyrmions (jointly with MA, O)

TT 14.7: Talk

Monday, March 16, 2015, 11:15–11:30, EB 301

Field-dependent Size and Shape of Single Magnetic Skyrmions — •Niklas Romming, André Kubetzka, Christian Hanneken, Kirsten von Bergmann, and Roland Wiesendanger — Department of Physics, University of Hamburg, 20355 Hamburg, Germany

Skyrmions are spatially localised solitonic magnetic whirls with axial symmetry and fixed rotational sense. They have recently been observed in both non-centrosymmetric bulk crystals and in ultrathin transition metal films on heavy-element substrates as a result of sizable Dzyaloshinskii-Moriya interactions. In addition to their protected topology and nano-scale size, skyrmions can easily be moved by lateral spin currents and written as well as deleted by vertical spin-current injection. Here we use spin-polarised scanning tunnelling microscopy to directly reveal the field-dependent internal spin structure of individual skyrmions in a biatomic PdFe layer on Ir(111) [1] with atomic-scale precision. An analytical expression for the description of skyrmions is proposed, which can establish a connection between the original work - predicting magnetic skyrmions - and their experimentally determined magnetic-field dependent size and shape. Thus, the relevant material parameters responsible for skyrmion formation can be determined. [1] N. Romming et al., Science 341, 636 (2013).