Relaxation processes in phonon-impuriton system and effective thermal conductivity of superfluid 3He-4He solutions

By the method of stationary thermal flow, the measurements of effective thermal conductivity in the superfluid solution 3He-4He with initial molar concentration 9.8% 3He in the temperature range 0.1-0.5 K have been carried out. At temperatures below 0.23 K, where the phase separation of the mixture occurs, the measurements were carried out in the lower superfluid phase with changing concentration following the phase diagram with decreasing the temperature. Experimental data were compared with the prediction of the kinetic theory of the phonon-impuriton system of a solution. The analysis allows us to establish the relaxation time hierarchy in such a system and to provide the quantitative estimation of the times of impuriton-impuriton and phonon-impuriton relaxation. It is shown that a rather good agreement between experimental data and theory can be obtained by the use of one fit parameter.