Magnetic nanowires are attracting significant interest as functional elements in spintronics and magnetic sensing due to their tunable geometry-dependent properties. Despite advances in synthesis and compositional control, the nanoscale characterization of local magnetic features remains challenging. In this study, led by Umberto Celano at Arizona State University, scanning nitrogen-vacancy magnetometry with the Qnami ProteusQ was employed to achieve non-perturbative field distribution mapping and minimally invasive magnetic imaging with high sensitivity. This approach enabled the localization of ultra-scaled magnetic defects with lateral dimensions below 50 nm and revealed previously inaccessible magnetic inhomogeneities associated with periodic geometrical modulations in axially magnetized nanowires. Comparisons with magnetic force microscopy confirmed the unique capability of scanning NV magnetometry to detect subtle magnetization fluctuations. Furthermore, the strong confinement of the nanowires’ stray fields was used to study their interaction with NV fluorescence, providing insight into the underlying contrast formation mechanisms. 

Read more: Nanoscale, 2024,16, 16838-16843