Impact of focused ion beam-induced damage on micromechanical properties in Hematite

Focused ion beam (FIB) milling is a common technique for microscale fabrication, however, this method is also known to alter the surface defect properties, affecting mechanical deformation response. This study investigates the effects of Ga⁺ and Xe⁺ sources on the mechanical response of ‘near dislocation free’ Hematite α-Fe₂O₃ single crystals using micropillar compression with samples oriented along [0001], [$0\overline{1}10$], and [$5\overline{5}02$] compression axes. Although the extent of difference in mechanical properties between Ga⁺ and Xe⁺FIB varied across crystallographic compression directions, the critical resolved shear stress (CRSS) measured in Xe⁺ FIB was consistently higher. This marked difference in CRSS was attributed to microstructural differences and higher interaction volume in Ga⁺ compared to Xe⁺ FIB. The anisotropic response of the ion beam damage on CRSS has also been reported.