Abstract
We have developed a highly sensitive torsional oscillator technique for probing the effect of the substrate character on the Kosterlitz–Thouless [1] transition in thin helium films. We have measured the vortex diffusivity in thin superfluid helium films adsorbed on a hydrogen pre-plated gold substrate. Helium adsorbed on such a surface exhibits the Kosterlitz–Thouless transition at pressure substantially higher than that for helium adsorbed on a gold substrate. We study finite amplitude and frequency effects for substrate velocities up to 32 cm/ s and in the frequency range from 3.3 to 36 MHz for single quartz crystal microbalance.
Published Version
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