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 1 ¯ 10 ], and [ 5 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.