Thermodynamic properties of thin films of superfluid 3He-A

The pairing correlations in superfluid He-3 are strongly modified by quasiparticle scattering off a surface or an interface. We present theoretical results and predictions for the order parameter, the quasiparticle excitation spectrum and the free energy for thin films of superfluid He-3. Both specular and diffuse scattering by a substrate are considered, while the free surface is assumed to be a perfectly reflecting specular boundary. The results are based on self-consistent calculations of the order parameter and quasiparticle excitation spectrum at zero pressure. We obtain new results for the phase diagram, free energy, entropy and specific heat of thin films of superfluid He-3.Comment: Replaced with an updated versio

Critical temperature and critical current of thin-film superfluid 3He

Superfluid3He film flow over the rim of a copper beaker has been measured. The flow rate was measured as a function of temperature and as a function of depth of3He below the rim or film thickness at the rim. The critical current, calculated from the flow rate, varied as (1 -T/Tc p)3/2 as expected for pair-breaking;Tc p is a film-thickness-dependent critical temperature. However, the magnitude of the current was an order of magnitude smaller than expected for pair-breaking, in agreement with other experiments that have demonstrated a lower dissipation mechanism in superfluid3He. The suppression of the critical temperature Tc p/Tc b, where Tc b=0.93 mK is the bulk3He transition temperature, varied from 0.93 to 0.7 as the film thickness at the rim varied from 120 to 90 nm. These ratios are larger than expected from Ginzburg-Landau or microscopic theory of superfluid3He-B. \ua9 1988 Plenum Publishing Corporation.Peer reviewed: YesNRC publication: Ye