Regensburg 2007 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 18: Electronic properties I

MM 18.1: Talk

Tuesday, March 27, 2007, 11:45–12:00, H6

Energy Loss Magnetic Chiral Dichroism: theory and experiments — •Stefano Rubino¹, Michael Stöger-Pollach¹, Cécile Hébert¹, Peter Schattschneider¹, Jan Rusz², and Pavel Novak² — ¹Institute for Solid State Physics, Vienna University of Technology, Wiedner Hauptstrasse 8-10/138, A-1040 Vienna, Austria — ²Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnickà 10, 162 53 Prague 6, Czech Republic

The Transmission Electron Microscope (TEM) has been able to detect Linear Dichroism since many years, yet the possibility to use it to measure circular dichroism as well was only predicted in 2003 and experimentally verified recently with TEM and synchrotron measurements on the same specimen. Angle resolved Electron Energy Loss Spectrometry (EELS) offers several experimental setups able to detect the dichroic signal in the TEM. The choice of the experimental setup influences the achievable spatial resolution as well as the signal to noise ratio. In the experiment, a coherent superposition of two momentum transfer vectors perpendicular to each other is set up, tuning the phase difference between the two interactions to 90°. The inelastic interference term carries the dichroic signature. Experimental details and recent experimental results on Ni, Fe and Co will be presented, as well as simulations. Calculations were done with a full-potential, fully-relativistic Augmented Plane Wave code based on Density Functional Theory. The EMCD technique provides a new analytical tool for the element specific study of local magnetic moments.