HE-3-HE-4 MIXTURES IN AEROGEL

Superfluid density and heat capacity experiments on He-3-He-4 mixtures in 98% porous aerogel show that in this system the coexistence boundary is detached from the superfluid transition line. The tricritical point is removed, and there is a superfluid phase on the He-3 rich side of the phase diagram. The presence of heat capacity peaks along the transition line down to a 4He concentration of only 8% indicates the 3-dimensional nature of this transition.