OPTICAL INTERFEROMETRY IN PHASE-SEPARATED HE-3-HE-4 MIXTURE FILMS

We report on interferometric studies of He-3-He-4 liquid mixtures. Anomalous wetting phenomena were observed in phase separated mixture films: the upper He-3-rich phase did not wet the lower He-4-rich phase under a small continuous feed of 4He atoms to the vapor phase. Instead, under this dynamic situation, floating pools of the 3He-rich phase were stabilized with a contact angle on the order of 10 mrad. In equilibrium, the concentrated 3He-rich phase was found to nucleate uniformly on the free surface, consistent with Antonow's rule.