The nature of ion milling damage in MoSi 2

Circular defects having strain and displacement contrast in transmission electron microscope images have been frequently reported at dislocations in MoSi . The origin of this contrast has been associated with deformation2 induced effects. However, by comparing samples that had been prepared either by electropolishing or by ion-beam milling during the final stage of thinning, it has been shown that these features are an artefact of ion-beam thinning. A detailed analysis of the contrast from the defects, as well as their thermal stability, suggest that they are platelets of argon introduced during the ion milling process.