Correlative Study of Domain Wall Motion and Pinning at Low Currents in Vortex-like Cylindrical Nanowires.

Cylindrical magnetic nanowires are promising building blocks for next-generation spintronic devices, thanks to their potential for fast and stable domain wall (DW) propagation in three-dimensional architectures. However, energy-efficient propagation remains a major challenge which requires reducing DW drive current and improving control and reproducibility. We demonstrate reproducible Oersted-field-driven DW motion in cylindrical Permalloy (Fe20Ni80) nanowires with chemical modulations (Fe70Ni30) at ultralow current density thresholds (j = 4.5 × 109 A/m2). By tailoring the nanowire geometry to promote azimuthal magnetization, the Oersted field interacts with the magnetic domains, enabling efficient and controlled DW propagation under nanosecond current pulses. Combining transmission X-ray microscopy (TXM) and transmission electron microscopy (TEM), we correlate the magnetic behavior with structural and chemical properties at both designed and unintentional pinning sites. Correlative imaging reveals that unintentional pinning is not associated with compositional changes, but rather with subtle local variations in crystallinity. These results position nanowires in which vortex states can be stabilized as a promising platform for low-power spintronic applications and provide insights into domain wall pinning mechanisms at the nanoscale.