Magnetic domain wall skyrmions

It is well established that the spin-orbit interaction in heavy\nmetal/ferromagnet heterostructures leads to a significant interfacial\nDzyaloshinskii-Moriya Interaction (DMI) that modifies the internal structure of\nmagnetic domain walls (DWs) to favor N\\'{e}el over Bloch type configurations.\nHowever, the impact of such a transition on the structure and stability of\ninternal DW defects (e.g., vertical Bloch lines) has not yet been explored. We\npresent a combination of analytical and micromagnetic calculations to describe\na new type of topological excitation called a DW Skyrmion characterized by a\n$360^\\circ$ rotation of the internal magnetization in a Dzyaloshinskii DW. We\nfurther propose a method to identify DW Skyrmions experimentally using Fresnel\nmode Lorentz TEM; simulated images of DW Skyrmions using this technique are\npresented based on the micromagnetic results.\n