Dresden 2009 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 33: Postersession Correlated Electrons: Metal Insulator Transition, Spin Systems and Itinerant Magnets

TT 33.9: Poster

Wednesday, March 25, 2009, 14:00–18:00, P1A

Doping dependence of stripe order in La_2−xSr_xNiO_4+δ — •Christoph Trabant¹, Hsueh-Hung Wu^1,2, Marcel Buchholz¹, Enrico Schierle³, Mohammed Benomar¹, Agung Nugroho⁴, Alexander Komarek¹, Ralf Feyerherm³, Markus Braden¹, Liu Hao Tjeng¹, and Christian Schüßler-Langeheine¹ — ¹II. Physikalisches Institut, Universität zu Köln — ²NSRRC, Hsinchu, Taiwan — ³Helmholtz-Zentrum Berlin — ⁴Bandun University, Indonesia

Stripe order in La_2−xSr_xNiO_4+δ with a doping level n_h=x+2δ between 0.2 and 0.33 exhibits an unusual temperature dependence of the correlation length, which goes through a maximum at intermediate temperatures and decreases not only upon heating but also upon cooling. While the integrated intensity of the charge and spin order peak is conserved, the system breaks into smaller and smaller domains when cooled.

We studied this behavior as a function of Sr and oxygen content using resonant diffraction at the Ni 2p → 3d (L_2,3) and 1s → 4p (K) thresholds. The goal is to understand the mechanism for the low-temperature broadening. Differences between commensurate and incommensurate order as well as the effect of the oxygen content will be discussed.

Supported by the DFG through SFB 608 and by the BMBF through 05 ES3XBA/5.