Thermal conductivity of the S 1/2 quasi-one-dimensional ferromagnetic spin system CsCuCl₃

We have measured the thermal conductivity along the c-axis, κ_c, parallel to ferromagnetic spin-chains of single crystals of the S 1/2 quasi-one-dimensional spin system CsCuCl₃ in magnetic fields up to 14 T, in order to investigate the thermal conductivity due to spins, κ_spin, and the change of thermal conductivity corresponding to the change of the spin state. In the temperature dependence of κ_c, no contribution of κ_spin has been observed, while a dip has been observed at the antiferromagnetic phase transition temperature, T_N. Furthermore, it has been found that κ_c at a low temperature of 5.1 K below T_N changes with increasing field perpendicular to the c-axis in good correspondence to the field-induced change of the spin state.