Regensburg 2000 – wissenschaftliches Programm

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TT: Tiefe Temperaturen

TT 15: Grundlegende Experimente zur Supraleitung

TT 15.5: Vortrag

Mittwoch, 29. März 2000, 16:45–17:00, H20

Stripe Correlations in Transition Metal Oxides: A Study of the Heat Transport — •C. Hess¹, J. Strohmenger¹, D. Cassel¹, J. Geck¹, R. Keßler¹, O. Friedt¹, U. Ammerahl^1,2, M. Hücker¹, B. Büchner¹, R. Gross¹, M. Braden³, T. Niemöller⁴, A. Revcolevschi², and S-W. Cheong⁵ — ¹Lehrstuhl für Angewandte Physik, II. Physikalisches Institut, Universität zu Köln, Zülpicher Str. 77, D-50937 Köln — ²Université Paris-Sud, 91405 Orsay Cédex, France — ³LLB, CE-Saclay, 91191 Gif-sur-Yvette, France — ⁴HASYLAB at DESY, Notkestr. 85, D-22603 Hamburg — ⁵Bell Laboratories, Lucent Technologies, Murray Hill, NJ 07974

We discuss the thermal transport (κ) of isostructural cuprates, nickelates and manganites. For the cuprates, κ is strongly suppressed in superconducting compounds, as compared to κ of non-superconducting samples. The thermal conductance of the cuprates can be well understood within a stripe scenario. Our interpretation also holds for stripe ordering nickelates and manganites where stripe ordering is long range. In the case of La_2−xSr_xNiO₄, κ depends systematically on the correlation length of stripe order: κ is largest for x=1/3 where stripe order is long range and is strongly suppressed for short range ordering compounds with x≠1/3. In addition we present recent results of neutron- and x-ray- diffraction on La_1.8−xEu_0.2Sr_xCuO₄ (x=0.8, 0.12, 0.15). In the case of x=0.15 a static magnetic superstructure is present below 30K. However, in our experiments we did not find any evidence for a charge superstructure. Supported by the DFG through SFB 341.