TEM images showing the np-Fe⁰ particles within the vapor deposition layer. Image (a) Fa100-P25mJ experiment, (b) Fa₂₉-P5mJ experiment, (c) Fa₂₉-P25mJ experiment, (d) Fa₂₉-P75mJ experiment, and (e) Fa₂₉-M75mJ experiment. The np-Fe⁰ particles formed via vapor deposition were distinct in distribution and grain size compared to those in the middle and bottom of the amorphous layer. The former were evenly small and present close to the upper boundary of the vapor deposition layer, indicating different formation pathways from those in the amorphous and subsolidus layers.