Observation of Bloch-point domain walls in cylindrical magnetic nanowires.

Topological protection is an efficient way of warranting the integrity of quantum and nanosized systems. In magnetism, one example is the Bloch point, a peculiar three-dimensional object implying the local vanishing of magnetization within a ferromagnet. By combining surface and transmission x-ray magnetic circular dichroism photoemission electron microscopy, we experimentally confirm the existence of the simplest magnetization texture holding a Bloch point at rest: the Bloch-point domain wall in cylindrical magnetic nanowires. This opens the way to the experimental search for peculiar phenomena predicted during the motion of these protected Bloch-point-based domain walls. [ABSTRACT FROM AUTHOR]