Temperature and concentration gradients in superfluid 3He-4He mixtures under steady-state conditions

The temperature and concentration gradients delT and delx are measured in a superfluid He-3-He-4 mixture with a concentration 9.8% of He-3 in the temperature range 70-500 mK. The gradients are produced by a steady thermal flow Q and registered by two thermometers and two capacitive concentration gauges. It is shown that the relationship between the steady values of delT and delx in the superfluid solutions is in agreement with a theoretical model derived from the temperature and concentration dependencies of the osmotic pressure. From the results obtained in the experiment we found the thermal diffusion ratio of the solution responsible for the thermal diffusion coefficient. (C) 2003 Elsevier Science B.V. All rights reserved.