SPECIFIC HEAT OF HE3-HE4 MIXTURES VERY NEAR LAMBDA LINE

We have measured the specific heat of liquid He4 and four He3-He4 mixtures under their saturated vapor pressure at temperatures very close to the λ temperature of each mixture. The specific heat of mixtures with large He3 concentration is clearly cusped at the λ line. It approaches a finite maximum with infinite slope. This supports the conjecture that the specific heat of He3-He4 mixtures at constant chemical potential becomes infinite at the λ line at all He3 concentrations. © 1969 The American Physical Society.