Regensburg 2002 – wissenschaftliches Programm

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TT: Tiefe Temperaturen

TT 22: Postersitzung III: Syst. korr. Elektr.: Theorie II (1-15), Metall-Isol.- und Phasenüberg
änge (16-33), SL: Massivmat., Bandl., Pinning, Vortexdyn., Transport, Korngr. (34-43), Niedrigdim. Syst., Magnetotransport (44-63)

TT 22.30: Poster

Donnerstag, 14. März 2002, 14:00–17:30, A

Resonant x-ray scattering study of structural distortions in La_7/8Sr_1/8MnO₃ — •Jochen Geck¹, Sven Kiele², Pascal Reutler¹, Bernd Büchner¹, and Peter Wochner³ — ¹II. Physikalisches Institut der RWTH Aachen — ²HASYLAB am DESY, Hamburg — ³Max-Planck-Institut für Metallforschung, Stuttgart

The study of the strong electronic correlations in doped transition metal oxides is one of the central issues of current condensed matter research. In this respect, lightly doped La_1−xSr_xMnO₃ provides a particular illuminating example, displaying a great variety of intriguing ordering phenomena. Especially, the ferromagnetic insulating ground state of La_1−xSr_xMnO₃ which develops around x=1/8 and its the microscopic structure remain to be fully understood. In order to clarify the microscopic properties of this possibly charge and orbital ordered state, we used resonant x-ray scattering (RXS) as a probe for occurring lattice distortions. The presented data shows that the crystal symmetry of La_7/8Sr_1/8MnO₃ is neither orthorhombic in the collective Jahn-Teller-distorted phase below 280 K, nor in the ferromagnetic insulating phase below 150 K. Furthermore, our measurements point to the presence of substantial distortions of the MnO₆-octahedra due to tilting, i.e. a non rigid rotation of the MnO₆-octahedra. The gained structural information might be relevant for the understanding of the unusual physical properties of lightly doped La_1−xSr_xMnO₃.