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TT: Tiefe Temperaturen

TT 7: Niedrigdimensionale Systeme

TT 7.2: Vortrag

Dienstag, 25. März 2003, 10:00–10:15, HSZ03

Structural Properties of the Spin Ladder and Chain Compound Sr₁₄Cu₂₄O₄₁ — •M. v. Zimmermann¹, J. Geck², S. Kiele^1,2, R. Klingeler², and B. Büchner² — ¹Hamburger Synchrotronstrahlungslabor HASYLAB at Deutsches Elektronen Synchrotron DESY, Notkestr. 85, 22603 Hamburg, Germany — ²II. Physikalisches Institut / Lehrstuhl A, RWTH Aachen, Huyskensweg, 52056 Aachen, Germany

Spin chain and ladder materials are an exciting class of compounds since the basic structural unit is similar to high-T_c superconductors. While in the superconductors CuO₄ plaquttes form a 2-dimensional network, in ladders and chains materials they compose 1-dimensional arrays. Sr₁₄Cu₂₄O₄₁ is one such material that exhibits both chains and ladders in subsequent layers and is particular exciting since it also shows superconductivity under pressure at a certain doping level. The average valence state of Cu in Sr₁₄Cu₂₄O₄₁ is 2.25 and the insulating ground state indicates that the holes are localized. A charge valence ordering at a temperature around 200 K is claimed by many different experimental techniques. However, the correlation of the holes is still uncertain. We have characterized a single crystal of Sr₁₄Cu₂₄O₄₁ with high energy (100 keV) x-ray diffraction, and find a strong incommensurate modulation. We will show how this modulation is related to charge ordering and discuss its consequences to the inter-chain correlation.