Abstract
The thermal conductivity κ of the spin-(1/2) chain cuprate BaCu2Si2O7 was measured along different crystallographic directions in the temperature region between 0.5 and 300 K. The thermal conductivity along the chain direction considerably exceeds that along perpendicular directions. Near the antiferromagnetic transition at TN = 9.2 K the data indicates enhanced scattering of phonons by critical fluctuations in the spin system. A comparison of the data above TN with available results on similar materials reveals similarities in the main features of the temperature dependence of the mean free path of itinerant spin excitations. This universal behavior is most likely caused by the spin-lattice interaction.