The Dzyaloshinskii–Moriya interaction (DMI) in magnetic systems stabilizes spin textures with preferred chirality, applicable to next‐generation memory and computing architectures. In perpendicularly magnetized heavy‐metal/ferromagnet films, the interfacial DMI originating from structural inversion asymmetry and strong spin‐orbit coupling favors chiral Néel‐type domain walls (DWs) whose energetics and mobility remain at issue. Here, a new effect is characterized in which domains expand unidirectionally in response to a combination of out‐of‐plane and in‐plane magnetic fields, with the growth direction controlled by the in‐plane field strength. These growth directionalities and symmetries with applied fields cannot be understood from static treatments alone. The authors theoretically demonstrate that perpendicular field torques stabilize steady‐state magnetization profiles highly asymmetric in elastic energy, resulting in a dynamic symmetry breaking consistent with the experimental findings. This phenomenon sheds light on the mechanisms governing the dynamics of Néel‐type DWs and expands the utility of field‐driven DW motion to probe and control chiral DWs.

Ferromagnet/heavy metal multilayer thin films with C2v symmetry have the potential to host antiskyrmions and other chiral spin textures via an anisotropic Dzyaloshinkii-Moriya interaction (DMI). Here, we present a candidate material system that also has a strong uniaxial magnetocrystalline anisotropy aligned in the plane of the film. This system is based on a new Co/Pt epitaxial relationship, which is the central focus of this work: hexagonal closed-packed Co(1 0 . 0)[0 0 . 1] facecentered cubic Pt(1 1 0)[0 0 1]. We characterized the crystal structure and magnetic properties of our films using X-ray diffraction techniques and magnetometry respectively, including q-scans to determine stacking fault densities and their correlation with the measured magnetocrystalline anisotropy constant and thickness of Co. In future ultrathin multilayer films, we expect this epitaxial relationship to further enable an anisotropic DMI and interfacial perpendicular magnetic anisotropy. The anticipated confluence of these properties, along with the tunability of multilayer films, make this material system a promising testbed for unveiling new spin configurations in FM/HM films.

We present a mechanism for deterministic control of the Bloch chirality in magnetic skyrmions originating from the interplay between an interfacial Dzyaloshinskii-Moriya interaction (DMI) and a perpendicular magnetic field. Although conventional interfacial DMI favors chiral Néel skyrmions, it does not break the energetic symmetry of the two Bloch chiralities in mixed Bloch-Néel skyrmions. However, the energy barrier to switching between Bloch chiralities does depend on the sense of rotation, which is dictated by the direction of the driving field. Our analysis of steady-state Dzyaloshinskii domain wall dynamics culminates in a switching diagram akin to the Stoner-Wohlfarth astroid, revealing the existence of both monochiral and multichiral Bloch regimes. Furthermore, we discuss recent theory of vertical Bloch line-mediated Bloch chirality selection in the precessional regime and extend these arguments to lower driving fields. This work establishes that applied magnetic fields can be used to dynamically switch between the chiral Bloch states of domain walls and skyrmions as indicated by this new Dzyaloshinskii astroid.