  Topologically protected magnetic structures such as skyrmions and domain
walls (DWs) have drawn a great deal of attention recently due to their thermal
stability and potential for manipulation by spin current, which is the result
of chiral magnetic configurations induced by the interfacial
Dzyaloshinskii-Moriya Interaction (DMI). Designing devices that incorporate DMI
necessitates a thorough understanding of how the interaction presents and can
be measured. One approach is to measure growth asymmetry of chiral bubble
domains in perpendicularly magnetized thin films, which has been described
elsewhere by thermally activated DW motion. Here, we demonstrate that the
anisotropic angular dependence of DW energy originating from the DMI is
critical to understanding this behavior. Domains in Co/Ni multi-layers are
observed to preferentially grow into non-elliptical teardrop shapes, which vary
with the magnitude of an applied in-plane field. We model the domain profile
using energetic calculations of equilibrium shape via the Wulff construction,
which explains both the teardrop shape and the reversal of growth symmetry at
large fields.

Materials Science