Competition Between the Superfluid Overlayer and the Mobile Solid Layer of 3He-4He Mixture Films on Porous Gold

Abstract

In the previous quartz crystal microbalance measurements for 4He films adsorbed on porous gold, we have observed a competition between superfluidity and slippage: In low areal densities, the resonance frequency increases gradually below T S due to the slippage of solid layer, while at high areal densities the slippage disappears and the superfluid onset of liquid overlayer is observed at T C . In the crossover region, the slippage below T S is suddenly suppressed at T D , which is much lower than T C . In the present work, we introduced a small amount of 3He onto 4He films, and studied the competition as a function of 3He areal density ρ 3. As ρ 3 is increased, T C is monotonically lowered. In contrast, T D increases up to a certain value of ρ 3, and then turns over to decrease in parallel to T C .