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TT: Fachverband Tiefe Temperaturen

TT 40: Correlated Electrons: Low-dimensional Systems - Materials 3

TT 40.5: Vortrag

Donnerstag, 29. März 2012, 16:00–16:15, H 0104

High temperature magnetic heat transport of low-dimensional quantum antiferromagnets — •Oleg Mityashkin¹, Ashwin Mohan¹, Nikolai Hlubek¹, Mahmoud Abdel-Hafiez¹, Christian Hess¹, Bernd Büchner¹, Surjeet Singh², Romuald Saint-Martin³, and Alexandre Revcolevschi³ — ¹Leibniz-Institut für Festkörper- und Werkstoffforschung, Dresden, Germany — ²Indian Institute of Science Education and Research (IISER), NCL Innovation Park, Pune, India — ³Laboratoire de Physico-Chimie de L’Etat Solide, Universite Paris-Sud, 91405 Orsay, France

We have investigated the magnetic heat transport of several cuprate materials realizing low dimensional S=1/2 quantum antiferromagnets, in the temperature range [7, 650] K. The results at low temperatures have been obtained using a four-point steady state method, whereas for high temperatures a dynamical laser flash analysis has been employed. In particular, we have studied the spin chain material SrCuO₂ and the 2D AFM square lattice La₂CuO₄. We observe a strong suppression of the magnetic heat conductivity with increasing temperature. We analyze and discuss the behavior of the heat conductivity by considering several scattering processes, in particular defect scattering and phonon scattering. Surprisingly, the results for these compounds obtained with the dynamical laser flash method vary with sample thickness. We associate this with a fundamental problem of this measurement technique.