Transmission electron microscopy (TEM) investigations were carried out in a ThermoFisher Spectra 300 at 300 kV. The TEM is equipped with a high-brightness Schottky Field Emission Gun (X-FEG). The STEM images were recorded with a HAADF detector using a dwell time of 10 µs. The camera length was set to 115 mm and the convergence angle to 22.5 mrad. The chemical composition was measured by energydispersive X-ray analysis (EDX). For this the TEM is equipped with a Thermo Fisher Super-X EDX detector.