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TT: Fachverband Tiefe Temperaturen
TT 44: Poster Session Correlated Electrons
TT 44.74: Poster
Thursday, March 17, 2011, 10:00–13:00, P1
Thermal relaxation and heat transport in spin ice Dy2Ti2O7 — •Bastian Klemke1,2, M. Meissner1,2, P. Strehlow2,3, K. Kiefer1, S. A. Grigera4,5, and D. A. Tennant1,2 — 1Helmholtz-Zentrum Berlin — 2Technische Universität Berlin — 3Physikalisch Technische Bundesanstalt, Institut Berlin — 4School of Physics and Astronomy, St. Andrews, UK — 5Instituto de Física de Líquidos y Sistemas Biológicos, CONICET, UNLP, La Plata, Argentina
The thermal properties of single crystalline Dy2Ti2O7 have been studied at temperature below 30 K and magnetic fields applied along [110] direction up to 1.5 T. Based on a thermodynamic field theory (TFT) various heat relaxation and thermal transport measurements were analysed. So we were able to present not only the heat capacity of Dy2Ti2O7, but also for the first time the different contributions of the magnetic excitations and their corresponding relaxation times in the spin ice phase. In addition, the thermal conductivity and the shortest relaxation time were determined by thermodynamic analysis of steady state heat transport measurements. Finally, we were able to reproduce the temperature profiles recorded in heat pulse experiments on the basis of TFT using the previously determined heat capacity and thermal conductivity data without additional parameters. Thus, TFT has been proved to be thermodynamically consistent in describing three thermal transport experiments on different time scales. The observed temperature and field dependencies of heat capacity contributions and relaxation times indicate the magnetic excitations in the spin ice Dy2Ti2O7 as thermally activated monopole-antimonopole defects.