NMR and superfluidity of 3He in 3He-4He solutions

Two possibilities of determining the superfluid transition temperature for 3He in a 3He-4He solution by the NMR technique are discussed. One of the methods consists in measuring the spin diffusion coefficient in weak magnetic fields at ultralow temperatures, and the other in measuring the ratio of the spin diffusion coefficient to the spin wave absorption coefficient at not very low temperatures. The transition temperature is estimated on the basis of the available experimental data. The effect of the superfluid transition in a system of 3He quasiparticles on the propagation of transverse spin waves and longitudinal spin-sound oscillations in 3He-4He solutions is studied. It is shown that there is a range of weak magnetic field intensities restricted from both sides in which the propagation of weakly damped spin-sound waves is possible