Dresden 2014 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 28: Magnetic Materials I
MA 28.9: Vortrag
Mittwoch, 2. April 2014, 17:15–17:30, HSZ 04
X-ray absorption magnetic circular dichroism study on ferromagnetic SrRuO3 — •Stefano Agrestini1, Zhiwei Hu1, Nils Hollmann1, Chang-Yang Kuo1, Qiang Liu1, Eric Pellegrin2, Pierluigi Gargiani2, Philipp Gegenwart3, Melanie Schneider3, Sebastian Esser3, Alexander Komarek1, and Liu Hao Tjeng1 — 1Max Planck Institut CPfS, Dresden, Germany — 2CELLS-ALBA, Barcelona, Spain — 3I. Physikalisches Institut, Georg-August-Universität, Göttingen, Germany
SrRuO3 have received intensive research interest because it is one of the very few ferromagnetic metallic 4d transition metal oxides, with a high Curie temperature of Tc=160 K, as well as unusual negative spin polarization and magnetoresistive properties. Ru4+ has S=1 spin state, however, very recently it has been suggested that a high spin state (S=2) of Ru4+ could be stabilized on compressively in-plane strained SrRuO3 films.
Here we report a study of x-ray magnetic circular dichroism (XMCD) in x-ray absorption (XAS) on the Ru-L2,3 edge on SrRuO3 thin films with different substrate orientations, the (111) and (001) surfaces of SrTiO3. Only a very small directional dependence was found. The XMCD spectra of a SrRuO3 single crystal has been recorded and shows good agreement with the spectral line shape of the thin films. We could not find evidence of the stabilization of a high spin S=2 state. Applying the XMCD sum rules, it can be seen that the orbital momentum of the Ru ions is almost quenched. This surprising finding could be explained by an itinerant character of the Ru electrons.