Self-organised stripe domains and elliptical skyrmion bubbles in ultra-thin epitaxial Au_0.67Pt_0.33/Co/W(110) films

Abstract

We studied the symmetry of magnetic properties and the resulting magnetic textures in ultra-thin epitaxial Au0.67Pt0.33/Co/W(110), a model system exhibiting perpendicular magnetic anisotropy and interface Dzyaloshinskii–Moriya interaction (DMI). As a peculiar feature, the C2v crystal symmetry induced by the Co/W interface results in an additional uniaxial in-plane magnetic anisotropy in the cobalt layer. Photo-emission electron microscopy with magnetic sensitivity reveals the formation of self-organised magnetic stripe domains oriented parallel to the hard in-plane magnetisation axis. We attribute this behavior to the lower domain wall energy when oriented along this axis, where both the DMI and the in-plane magnetic anisotropy favor a Néel domain wall configuration. The anisotropic domain wall energy also leads to the formation of elliptical skyrmion bubbles under a weak out-of-plane magnetic field.

Tailoring Magnetic Anisotropy in Ultrathin Cobalt by Surface Carbon Chemistry

“…In fact, almost all relevant studies point to an enhancement of Co PMA in the presence of carbon and to the existence of exotic magnetic domain structures in ultrathin Co films with PMA. [3,4] Notable examples of PMA enhancement were obtained by covering the Co surface with graphene, [5,6] C 60 , [7] and CO. [8] The adsorption site of CO was reported to have an important role in PMA. [9] Moreover, the dissociation of CO and the subsequent accumulation of carbidic and graphitic carbon on Co were shown to result in the strengthening of PMA.…”

Stabilization and racetrack application of asymmetric Néel skyrmions in hybrid nanostructures

“…Here, the axis-symmetry breaking has been achieved by an in-plane bias magnetic field 25 or by introducing a certain in-plane anisotropy 26 , for instance, by applying strain 26,27 . Recent studies show that also an anisotropic PMA and DMI can stabilize elliptical Néel-skyrmions in thin films 28,29 , that exhibit a considerable reduction of SHE 30 .…”

Towards hexagonal C2v systems with anisotropic Dzyaloshinkii-Moriya interaction: Characterization of epitaxial Co(101¯0)/Liu1, Kitcher2, Graef3 et al. 2021Phys. Rev. Materials1000View full textAdd to dashboardCite

“…Specifically, antiskyrmions are preferred over Néel skyrmions when the DMI has opposing signs along orthogonal crystallographic directions. To date, research on anisotropic DMI in FM/HM systems has focused on films based on a body-centered cubic (BCC) heavy metal [13,[15][16][17][18][19]. Moreover, across the limited experimental studies carried out thus far, a suitable antiskyrmion host has not been found.…”