Study of bulk longitudinal spin relaxation in He-3-He-4 liquid mixtures
Résumé
Longitudinal spin relaxation has been investigated in spin polarised liquid He-3-He-4 mixtures in cesium-coated glass cells. The contribution of wall relaxation is found to be either negligible or easy to separate, and bulk relaxation times can be derived front systematic studies. We report on relaxation measurements at saturated vapour pressure, for temperatures ranging from 1.1 to 3K. He-3 densities vary from 0.07 to 11 mmol.cm(-3) (He-3 concentrations between x(3) similar or equal to 0.3 and 34%), so that both normal and superfluid He-3-He-4 solutions are studied. At fixed temperature, the longitudinal relaxation time is inversely proportional to the He-3 number density over the whole range of investigated concentrations. In contrast, it is almost independent of temperature (changes do not exceed 10%). Comparison with published data and expected behaviours is discussed.