Nucleation of superfluid transitions in liquid helium mixtures

Superfluid transitions in liquid helium mixtures are studied in a continuum model including concentration and pressure gradients induced by the walls. The localization and growth of the new phases are obtained using the bulk phase properties. Relaxation times have been measured and they yield the onset superfluid temperature Tsub(lambdaS) for several mixtures above 0.9 (K). These results and others found in the literature are analysed in the model. A characteristic onset length is found which increases with the temperature