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TT: Fachverband Tiefe Temperaturen
TT 24: SC: Properties, Electronic Structure, Mechanisms
TT 24.13: Vortrag
Mittwoch, 24. März 2010, 17:45–18:00, H19
Low temperature disorder of the stripe phase in layered nickelates — Christoph Trabant1, Marcel Buchholz1, Chun-Fu Chang1, Ralf Feyerherm2, Enrico Schierle2, Esther Dudzik2, Alexander Komarek1, Agung Nugroho3, Mohammed Benomar1, Liu Hao Tjeng1,4, Markus Braden1, and •Christian Schüßler-Langeheine1 — 1II. Physikalisches Institut, Universität zu Köln — 2Helmholtz-Zentrum Berlin — 3Institut Teknologi Bandung — 4Max-Planck-Institut für Chemische Physik fester Stoffe, Dresden
In hole-doped layered nickelates and cuprates a collective order of charge and spin degrees of freedom is found, the so-called stripe phase. The holes arrange in lines, which act as domain walls for the antiferromagnetic order on the hole-poor sites. This order is formed upon cooling with a gradual increase of the correlation length. Remarkably the correlation length goes through a maximum and decreases again upon further cooling: The stripe order breaks apart at low temperatures. Generally not observed in neutron experiments, this effect has been predicted by theory as a consequence of competition between Coulomb repulsion and lattice potential. Also the effect of static disorder has been discussed. We present a systematic study of low-temperature disorder in doped nickelates using resonant diffraction in the conventional and soft x-ray range. We find that this effect depends mainly on the total doping level and affects spin order and charge order in a similar way. The influence of static disorder is found to be small. Funded by the DFG through SFB 608 and by the BMBF project 05KS7PK1.