Berlin 2008 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 32: Correlated Electrons: Poster Session

TT 32.16: Poster

Donnerstag, 28. Februar 2008, 14:00–18:00, Poster B

Magnetic linear dichroism as new tool to determinecrystal fields in cubic Ce, Yb and Pr compounds — •Peter Koerner, Maurits Haverkort, Thomas Willers, Zhiwei Hu, Andrea Severing, and Liu Hao Tjeng — Institute of Physics II, University of Cologne

We have recently shown that polarization dependent soft-x-ray absorption spectroscopy (using linearly polarized light) is a powerful tool to probe the charge distribution of the crystal-field ground state of Ce Heavy-Fermion and Kondo intermetallics with tetragonal site symmetry [1]. The so-called linear dichroic signal at the Ce M_4,5 edges can be very large and is easily measured, thereby providing accurate quantitative information. For cubic systems, however, this dichroic effect vanishes. We now explore theoretically the feasibility to generate a dichroic signal by applying a strong magnetic field to the cubic system, thereby still using linearly polarized light. In this poster we will present under which conditions the lifting of the degeneracy by the Zeeman splitting will give rise to a detectable linear dichroic effect which can provide information about the charge distribution of the crystal-field ground state in cubic Ce, Yb compounds and the Pr skuterudites.. We note that this type of magnetic linear dichroism is different from that observed in e.g. Fe₂O₃ [2].

[1] P. Hansmann, A. Severing, Z. Hu, M.W. Haverkort, C.F. Chang, S. Klein, A. Tanaka, H.H. Hsieh, H.J. Lin, C.T. Chen, B. Fak, P. Lejay, L.H. Tjeng , Cond-Mat 0710.2778v1

[2] e.g. P. Kuiper et al., Phys. Rev. Lett. 70, 1549 (1993).