3He film flow on a round rim beaker

The superfluid properties of thin (100–150 nm) of³He were investigated by measuring the rate at which a beaker of liquid³He emptied itself through the adsorbed film, with the film thickness decreasing as the level dropped. A beaker rim with a semicircular cross-section was used to provide a well defined geometry and to avoid the effects of small scratches that may have affected earlier experiments. The film thicknesses were determined by Atkins' oscillaton measurements of⁴He films on the same surface. The superfluid transition temperature in the filmT_c^F was suppressed below the bulk valueT_c^B, and was close to being described by 2/(T_c^F) = , as expected for A-phase. The critical current density was more than an order of magnitude smaller than expected for pair-breaking. When a⁴He monolayer was adsorbed on the substrate, there was no suppresson ofT_c^F.