Regensburg 2013 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 28: Magnetic Materials
MA 28.9: Vortrag
Mittwoch, 13. März 2013, 17:15–17:30, H22
Spectroscopic study of the Kondo semiconductors CeM2Al10 (M = Ru, Os and Fe) — •Fabio Strigari1, Thomas Willers1, Zhiwei Hu2, Chang-Yang Kuo2, Stefano Agrestini2, Andrea Severing1, and Liu Hao Tjeng2 — 1Institute of Physics II, University of Cologne — 2MPI for Chemical Physics of Solids, Dresden
The orthorhombic CeM2Al10 compounds with M = Ru, Os, and Fe belong to a fairly new family of Ce Kondo semiconductors, which exhibit a novel magnetic phase transition at T0 = 27 K (M = Ru) and 29 K (M = Os). The ordering mechanism is still a matter of debate since the ordering temperature is unexpectedly high and the ordered moment strongly reduced. The isostructural CeFe2Al10 lacks any phase transition and shows the highest degree of hybridization between 4f and conduction electrons within the family. For CeRu2Al10 and CeOs2Al10 the static magnetic susceptibility shows a strong anisotropy and Curie-Weiss behavior down to T0 and 40 K, respectively, whereas for CeFe2Al10 it suggests more intermediate valent behavior. Due to the presence of the crystalline electric field, the 4f ground state wave functions are expected to be highly anisotropic and their knowledge is essential to understand the magnetic properties in this compounds.
We performed extensive experimental studies by means of x-ray based spectroscopic techniques – namely soft x-ray absorption, resonant inelastic x-ray scattering and hard x-ray photoemission spectroscopy – in order to determine the crystal-field ground state and quantitatively analyze the 4f valence for the members of the 1-2-10 family.