Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
MA: Fachverband Magnetismus
MA 54: Spin Hall Effects and Skyrmions II
MA 54.11: Vortrag
Donnerstag, 23. März 2017, 17:45–18:00, HSZ 04
Magnetic skyrmions in Pt/Co/Ir at zero field — •Jochen Wagner1, Robert Frömter1, Kai Bagschik1, André Philippi-Kobs2, Rustam Rysov2, Leonard Müller2, Gerhard Grübel2, and Hans Peter Oepen1 — 1Institut für Nanostruktur- und Festkörperphysik, Uni Hamburg, Germany — 2DESY, Hamburg, Germany
X-ray holographic microscopy (XHM) has become a competitive technique to investigate magnetic domain patterns with sub-20-nm spatial resolution exploiting the x-ray magnetic circular dichroism [1].
We employed XHM to study a wedge-grown (Pt1 nm/Co0− 2 nm/Ir1 nm)6 multilayer. The absence of inversion symmetry yields a strong interfacial Dzyaloshinskii-Moriya interaction (DMI), which causes domain walls to be Néel like – in contrast to Pt/Co/Pt, where Bloch walls are expected. As a further, the consequence stabilization of skyrmionic bubbles and even skyrmion lattices through magnetic fields has been reported recently [2].
In the demagnetized state, we find the maze domain pattern with cobalt-thickness dependent domain sizes ranging from 100 nm to a few microns. In addition, circular domains of about 30 nm diameter are observed, unlike in symmetrical systems like Pt/Co/Pt. With the strong DMI present, these bubble domains can be considered as skyrmions. The skyrmions can be deleted by fully saturating the sample, and reappear after another demagnetization cycle. We assume therefore local defects to be responsible for their creation and zero-field stability.
[1] D. Stickler, et al., Appl. Phys. Lett. 96, 042501 (2010).
[2] C. Moreau-Luchaire et al., Nature Nanotech 11, 444-448 (2016).