Investigation of local chemical and electronic properties of small particles with EELS point analysis and image energy filtering in a STEM

The finely focused electron beam of a STEM microscope provides a very powerful probe for the investigation of the local chemical and electronic properties of small particles. After a general description of different techniques which have been developed to take benefit of the Electron Energy Loss Signal (EELS) in this configuration, we describe two experiments under progress. The first one concerns clusters of iron oxide particles in a magnetic superlattice, the second one deals with silicon spheres. These examples involve quite different excitations which are respectively more characteristic of the properties of the bulk (core loss edges) or of the surface (plasmon modes). (orig.)