Transition temperature for 4He liquid adsorbed in disordered media

For pure He-4 liquid the superfluid fraction starts having a finite value at and below the lambda-transition temperature 2.176K, whereas for He-4 in a disordered media the superfluid fraction starts having a finite value Lit 2.168K, a temperature that is lower compared to the temperature at which superfluidity appears in pure He-4. Relations for transition temperatures for both cases that are in agreement with experimental values have been obtained. Adsorption, which normally leads to a decrease in the degrees of freedom, consequently results in a release of heat, which destroys superfluidity. Hence for the liquid He-4 flowing into a disordered medium, the transition temperature is expected to be lower.