Berlin 2018 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 41: Surface magnetism I

MA 41.9: Vortrag

Donnerstag, 15. März 2018, 11:45–12:00, EB 202

X-ray spectroscopy of simple transition-metal–oxygen model systems — •Vicente Zamudio-Bayer^1,2, Rebecka Lindblad^1,3, Christine Bülow², Martin Timm², Konstantin Hirsch², Arkadiusz Ławicki², Akira Terasaki⁴, Bernd von Issendorff¹, and Tobias Lau² — ¹Physikalisches Institut, Universität Freiburg, 79104 Freiburg, Germany — ²Institut für Methoden und Instrumentierung der Forschung mit Synchrotronstrahlung, Helmholtz-Zentrum Berlin für Materialien und Energie, 12489 Berlin, Germany — ³Department of Physics, Lund University, 22100 Lund, Sweden — ⁴Department of Chemistry, Kyushu University, Fukuoka 812-8581, Japan

In the recent literature (Rau et al., Science 344, 988) it was demonstrated that a cobalt adatom on an MgO layer shows a record high magnetic anisotropy energy with an out-of-plane easy axis. The symmetry of the system is dominated by the uniaxial configuration of the cobalt atom on top of the oxygen site. With the dominating uniaxial configuration in mind, we have performed x-ray absorption and x-ray magnetic circular dichroism spectroscopy on free, diatomic ions consisting of a 3d metal and an oxygen atom (TM-O⁺ with TM = Mn, Fe, Co, Ni, Cu). We are thus able to study, at a fixed symmetry, trends and correlations between electronic configuration, orbital magnetic moment, and spin polarization in this model oxide systems. Moreover, we gain an improved understanding of how the interplay between symmetry, orbital occupation, and charge-transfer excitations influence the shape of the x-ray absorption spectra. Possible consequences of large MAE for the magnetization of free particles will also be discussed.