Temperature-Assisted Fabrication and Healing Process of α-Fe Nanopores at Atomic Scales

The ability to understand and control the healing mechanisms of magnetic iron (Fe) nanopores (NP) has important impact on its applications. This study applied in situ transmission electron microscopy (TEM) technology to systematically investigate the preparation and healing processes of Fe NPs. The main findings were as follows: (1) The preparation of Fe NPs. By adjusting the direction of the focused electron beam (e-beam) irradiation, different shapes of Fe NPs were successfully prepared. (2) Healing of Fe NPs. The healing process exhibited isotropic behavior when Fe atoms were uniformly distributed, whereas preferential healing occurred in regions with higher Fe atom concentration under nonuniform distribution conditions. The experiments revealed a healing mechanism characterized by "gradient-driven region-selective healing-interlayer cooperative reconstruction". This research plays a pivotal role in understanding the atom migration pathway during the healing process, shedding light on the healing mechanisms in Fe NPs and paving the way for exploiting their potential applications.