High resolution electron microscopy and nano-probe study of CoSm/Cr films

The crystal structure of the crystallites in CoSm thin films deposited on Cr underlayer was studied by nanodiffraction and high resolution electron microscopy (HREM). It was found that the crystallites have a closed-packed structure. Some nanodiffraction patterns taken from different crystallites using a two nanometer probe can be indexed by two layer stacking AB (HCP structure), three layer stacking ABC (FCC structure), and four layer stacking ABAC (double hexagonal structure), suggesting that a particular local stacking mode could exist. [112~0] HREM images confirmed that stacking sequence changes within one crystallite. In local regions, random stacking, and unit cells of two layer stacking ABAC were found.