Superfluid fraction of 3He-4He mixtures confined at 0.0483 μm between silicon wafers

We report measurements of the superfluid fraction rho (s)/rho of films of He-3-He-4 mixtures confined between silicon wafers at 0.0483 mum separation. The data obtained using adiabatic fountain resonance (AFR) can be used to test for the first time expectations of correlation-length scaling in the case of planar mixtures. For the mixtures, the data for rho (s)/rho collapse well on a universal function. The dissipation associated with AFR can also be scaled, and indicates two-dimensional crossover. These result, are in contrast to pure He-4, where over a wider range of confinements, thr data fur rho (s)/rho are found not to scale.