Office of the Secretary of Defense: 12_ORNL_Analysis_Metallic_Specimen

4
Finally, based on the postulated hypothetical uses of bismuth, the dielectric properties necessary for bismuth to
function as a waveguide would have been disrupted in this material because the bismuth in the specimen is co-
located and mixed with lead (Figures 3 and 5). Based on these findings ORNL determined that this material is highly
unlikely to have ever functioned as a bismuth-based terahertz waveguide.
5 μm
(a)
5 nm-1
(b)
5 μm 5 nm-1
γ =3.0
Bi2O3
Bi
(c) (d)
Figure 4: (a) TEM micrograph of a single-crystalline region from the bulk of the sample; structural defects are visible at
this level of resolution (this figure is showing an area that represents just 2 to 3 pixels of the area shown in Figure 3). The
vertical lines at the bottom are a focused ion beam preparation artifact. (b) Selected area electron diffraction pattern
(SAEDP) from the region in (a), indexed to the standard Mg structure. (c) A low-magnification montage TEM micrograph
of an area showing a dense bismuth-rich layer (dark central band). (d) A SAEDP from a bismuth-rich band. The electron
diffraction pattern (with image processing γ=3.0) from the bismuth-rich region is shown in the white rings. Both bismuth
(Bi, yellow) and Bi2O3 (red) calculated ring patterns are shown for comparison; Bi is a slightly better match. The diffraction
indicates that the bismuth layer is nanocrystalline and highly defective.012
Page determined to be Unclassified
Reviewed by Chief of Staff, AARO
IAW FY24 NDAA, Section 1841 (a)(1)(C)
Date: 02/06/2025