New EELS Spectrometer at Uppsala University

With the increasing use of the scanning transmission electron microscopy (STEM) technique in our aberration-corrected TEM, atomic resolution spectroscopy techniques have become feasible and contribute essentially to the understanding of modern materials. To build advanced analysis techniques and to analyse novel materials, Uppsala University decided to equip its current Titan Themis aberration-corrected TEM with an energy filter. The base of this energy filter is an electron energy loss spectrometer (EELS) where the elemental edges in the spectra obtain information about the structure and electronic structure of a material. The energy filter is equipped with two excellent cameras, one CMOS camera, mainly for energy-filtered imaging, and one hybrid camera for EELS spectroscopy.

With this energy filter, it is possible to characterise with down to subatomic resolution materials properties such as chemical composition, oxidation states, the structural allotropes that are locally present, interfacial electronic structures and magnetic moments to name a few.

Furthermore, the hybrid camera can acquire up to 13.000 images per second and allows therefore for the acquisition of 4-dimensional STEM maps of diffraction patterns to analyse strain, magnetic and electrical fields, and structure with very high resolution.

This CEFID energy filter is available for the collaboration partners of the ARTEMI infrastructure and will equally be used for building novel spectroscopy techniques for ARTEMI. We believe that the filter equipped with its excellent cameras is a disruptive change as compared to the previous generation of energy filter and will make many exciting applications feasible.