Observation of Circular Dichroism in EELS

The similarities between XANES (X-ray Absorption Near Edge Structure) and ELNES allow to measure Linear Dichroism in the TEM. A similar task for Circular Dichroism which is routinely studied in synchrotrons was considered impossible with present technology. The possibility to detect chiral electronic transitions in the TEM was recently demonstrated [1, 2]. This makes ELNES in the TEM a strong competitor of the synchrotron for X-ray Magnetic Circular Dichroism (XMCD) studies (Fig. 1). In analogy to XMCD we introduced the term EMCD: Energy loss Magnetic Chiral Dichroism. in order to stress that no spin polarization of the beam is needed; rather, the chirality of transitions is detected in a particular scattering geometry.