Fig. 2: TEM and STEM analysis of modified framboidal magnetite in a Ryugu grain. | Nature Astronomy

Fig. 2: TEM and STEM analysis of modified framboidal magnetite in a Ryugu grain.

From: Influx of nitrogen-rich material from the outer Solar System indicated by iron nitride in Ryugu samples

Fig. 2: TEM and STEM analysis of modified framboidal magnetite in a Ryugu grain.The alternative text for this image may have been generated using AI.

a, HAADF-STEM image of modified magnetite (Mgt). Pt-C is the protective platinum coat. b,c, STEM-EDX elemental maps of the modified magnetite. An RGB composite image of oxygen (red), iron (green) and silicon (blue) is shown in b and that of sulfur (red), nitrogen (green) and magnesium (blue) is in c. d,e, BF-TEM image (d) and DF-STEM image (e) of modified magnetite constructed from a STEM-NBD dataset. The DF-STEM image in e was produced by selecting a diffraction spot of roaldite, indicated in f. Dashed lines denote the boundaries of the iron-rich layer (I). The white areas in e correspond to high-intensity regions for the diffraction spot of roaldite. f, Position-averaged NBD pattern for the rectangular region covering the iron-rich layer and the substrate magnetite in e. Red circles indicate diffraction spots from roaldite (superscript R), which has a crystallographic relationship with magnetite (superscript M). The arrow shows the diffraction spot of roaldite chosen for producing the DF-STEM image in e. g, NBD pattern from the iron-rich layer in e. Diffraction spots of roaldite (arrowed) are dominant, and those of magnetite are weak in the layer. Sample ID is A0104-028098.

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