Vortex core size in superfluid³He-⁴He Mixture films

Abstract

Torsion oscillator measurements of the superfluid transition of³He-⁴He mixture films adsorbed on alumina powder have been carried out for superfluid coverages of less than one monolayer. The addition of³He substantially broadens the phase transition, indicating an increase in the vortex core size, by nearly a factor of two with the addition of about 0.13 layers of³He. The scaling of the core size with the superfluid coverage is similar to that found for pure⁴He films, in agreement with a simple Gross-Pitaevskii model for the core.