Regensburg 2010 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 27: CE: Poster Session

TT 27.30: Poster

Mittwoch, 24. März 2010, 14:00–18:00, Poster D1

Metal-insulator transitions in layered ruthenates — Johanna Brand¹, •Anna Silex¹, Olaf J. Schumann¹, Michael Gottschlich¹, Steven Price¹, Navid Qureshi¹, Paul Steffens^1,2, Daniel Löwen¹, Yvan Sidis³, Arsène Goukassov³, Beatrice Gillon³, Satoru Nakatsuji⁴, Jason Farrell⁵, Naoki Kikugawa⁵, Andrew Mackenzie⁵, Karin Schmalzl², and Markus Braden¹ — ¹II. Physik, Uni Köln — ²ILL, Grenoble — ³LLB, Saclay — ⁴ISSP, Tokio, Japan — ⁵Univ. of St. Andrews, Scotland

Ca- and Sr-Ruthenates are far more interesting than the structural similarity with the cuprates initially suggested. By doping the single or double layer materials, many interesting phenomena are observed. Substituting Ti into Sr₂RuO₄ stabilizes a spin-density wave (SDW) phase that still is metallic, in which the static ordering corresponds to the dominating magnetic instability in pure Sr₂RuO₄. On the other hand, the doping of Ti into the double layer material Sr₃Ru₂O₇ seems to induce a SDW type magnetic order with larger impact on the electronic properties. The SDW phase in Ti-doped Sr₃Ru₂O₇ does not seem to be related with the magnetic instabilities of the parent phase. In both Sr-ruthenates the impact of the Ti-doping on the crystal structure is small and changes slightly across the magnetic transition. However, we find a strong influence of the Ti-substitution in Ti-doped Ca₃Ru₂O₇ which significantly stabilizes a weakly non-metallic phase. This can be seen in the transition temperature and in the resistivity jump. A pronounced flattening of the lattice is discussed as a general feature accompanying the metal-insulator transition in layered ruthenates.