Regensburg 2010 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 9: SC: Poster Session

TT 9.8: Poster

Montag, 22. März 2010, 14:00–18:00, Poster A

Charge order in La_2−xBa_xCuO₄ studied by resonant soft x-ray diffraction — •Eugen Weschke¹, Victor Soltwisch¹, Enrico Schierle¹, Stuart P. Wilkins², Jochen Geck³, John P. Hill², John M. Tranquada², and Jörg Fink^1,3 — ¹Helmholtz-Zentrum Berlin für Materialien und Energie, Berlin, Germany — ²Brookhaven National Laboratory, Upton, New York, USA — ³Leibniz-Institut für Festkörper- und Werkstoffforschung, Dresden, Germany

La_2−xBa_xCuO₄ (x = 0.125 and x = 0.115) was studied by x-ray diffraction at the O-K and the Cu-L₃ resonances, in this way focussing on the O-2p and Cu-3d electronic structure. In both cases, pronounced charge-order superstructure peaks are observed directly below the temperature of the structural transition from the LTO into the LTT phase. This is in contrast to the case of La_1.8−xEu_0.2Sr_xCuO₄, where charge order occurs at a lower temperature than the structural phase transition. Further differences between the materials are observed in the coherence lengths of the charge order, which is significantly larger in case of La_2−xBa_xCuO₄. For the two resonances indications for a different evolution with temperature of the superstructure peaks in La_2−xBa_xCuO₄ are found.