Berlin 2018 – scientific programme

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MA: Fachverband Magnetismus

MA 41: Surface magnetism I

MA 41.6: Talk

Thursday, March 15, 2018, 10:45–11:00, EB 202

Step Edge Induced Anisotropic Chiral Spin Coupling Observed in Ultrathin Magnetic Films — •Stefan Krause, Anika Schlenhoff, and Roland Wiesendanger — Department of Physics, University of Hamburg, Germany

Breaking the symmetry at planar interfaces and surfaces results in a chiral spin coupling due to Dzyaloshinskii-Moriya interactions (DMI), driven by spin-orbit coupling. DMI stabilize an inhomogeneous right-rotating cycloidal spin spiral ground state in the Fe double layer (DL) on W(110), as has been demonstrated by means of spin-polarized scanning tunneling microscopy (SP-STM) [1]. In contrast, the Fe monolayer (ML) on W(110) is found to be ferromagnetic [2].

An atomic step edge separating DL and ML areas of coverage results in a breaking of the lateral symmetry of the film, potentially giving rise to localized additional DMI. In our SP-STM experiments we investigate the spin configurations around Fe/W(110) ML/DL step edges. The data give clear indications for a chiral spin coupling of the DL to the ML. Depending on the step edge orientation, the DL spin texture is locally affected by a deformation of the spin spiral and selection rules for the formation of 90^∘ domain walls. Interestingly, an inversion of the spin coupling chirality is found for step edges oriented along the [001] and close-packed crystallographic directions, respectively. The SP-STM data will be presented and discussed in terms of anisotropic chiral spin coupling of the DL to the ML.

[1] S. Meckler et al., Phys. Rev. Lett. 103, 157201 (2001).

[2] M. Pratzer et al., Phys. Rev. Lett. 87, 127201 (2001).