Sound Attenuation and 3He–3He Interaction in 3He–4He Liquid Mixtures under Pressure

Abstract

From sound attenuation measurements, 3He–3He interaction potentials in 3He–4He mixture under 10 and 20 bar have been determined. The measurements were carried out in mixtures of 3He mole fraction ranging from 0.0289 to 0.0803. Superfluid transition temperatures of 3He and other properties in the mixtures were then estimated from the deduced interaction potentials. The superfluid transition temperature for s-pairing was found to lower with increasing pressure, whereas a rather high transition temperature, as high as 100 µK, can be expected under 10 bar at the highest soluble 3He concentration.