Berlin 2012 – wissenschaftliches Programm
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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.