Dresden 2006 – wissenschaftliches Programm

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TT: Tiefe Temperaturen

TT 19: Correlated Electrons: Low-dimensional Materials

TT 19.2: Vortrag

Dienstag, 28. März 2006, 14:15–14:30, HSZ 301

Revisiting the magnetism of hole-doped CuO₂ spin chains in Sr_14−xCa_xCu₂₄O₄₁ — •Jürgen Schnack¹, Rüdiger Klingeler², Vladik Kataev², and Bernd Büchner² — ¹Universität Osnabrück, Fachbereich Physik — ²Leibniz-Institute for Solid State and Materials Research IFW Dresden, Germany

Magnetization measurements of Sr_14−xCa_xCu₂₄O₄₁ with 0 ≤ x ≤ 12 in magnetic fields up to 16 T show that the low temperature magnetic response of the CuO₂ spin chains changes strongly upon doping [1]. For x=0 quantum statistical simulations [2] yield that the temperature and field dependence of the magnetization can be well described by an effective Heisenberg model in which the ground state configuration is composed of spin dimers, trimers, and monomers [3]. Reduction of the number of holes in the chains through Ca-doping leads to an additional contribution to the magnetization, which depends linearly on the magnetic field. Remarkably, the slope of this linear contribution increases with the Ca content. We discuss this behavior in the context of an effective Heisenberg model for hole-doped spin chains [2].

[1] R. Klingeler et al., cond-mat/0511110

[2] J. Schnack, Eur. Phys. J. B 45 (2005) 311

[3] R. Klingeler et al., cond-mat/0508626