Slippage of Nonsuperfluid 4He Films on Ag

We measured the mechanical response of nonsuperfluid 4 He films adsorbed on a Ag substrate using the quartz-crystal microbalance technique. In 4 He coverages from 0.06 to 0.1 atoms/? 2 , we observed that the resonance frequency increases at low temperatures accompanied by a decease in Q-value. This behavior suggests that nonsuperfluid 4 He films undergo partial slipping relative to the Ag substrate.