Nova nanolab 600i dualbeam

The cross-section and lamella for TEM investigations were prepared by focused ion beam (FIB). FIB milling was carried out with a FEI Nova Nanolab 600i Dualbeam with a Ga ion beam following the standard procedure37 (link). We used electron induced Co and Pt deposition for protecting the region of interest and a final milling step at 5 kV to limit damage to the lamella. High-resolution TEM (HRTEM) and scanning TEM analyses were conducted using a JEM ARM200F aberration-corrected TEM operated at 200 kV. For the chemical analysis, energy-dispersive X-ray measurements were carried out using the same microscope equipped with a 100 mm² energy-dispersive X-ray silicon drift detector (SSD).

The samples after indentation were then used to make TEM samples along the TD and RD with a focused ion beam (FIB, FEI Nova NanoLab 600i DualBeam, Hillboro, OR, USA). The TEM samples were sliced along the major axis of the indentation along RD and TD (shown with a dashed line in Figure 3). For the Berkovich indentation, a thin layer of protective Pt was first applied to the sliced TEM samples. Then, a long rectangular shape (~10 × ~5 µm) was cut from the sliced TEM samples, extending from one corner to the end of the indentation along the major axis. Two trenches were cut on both sides of this rectangular pattern. The material formed between the trenches was then thinned to 1 μm. The sample was then transferred to Cu lift-out grids. It was then thinned to a final thickness of 100 nm (at 30 kV with 48 pA), which was then examined using a TEM (JEOL 2100F, Tokyo, Japan with integrated Oxford EDX, Abingdon, UK) at 200 kV in STEM mode.