The superfluid transition of 4He films adsorbed on Pt packed powders 500, 100, and 60 A in diameter has been studied using torsional oscillators. The behavior of the superfluid density near the transition differs considerably from earlier observations in films adsorbed on porous glass. For all the powder diameters, a narrow dissipation peak accompanies the transition unlike in the porous-glass case. The results are also In disagreement with the theories of the Kosterlitz-Thouless transition on a sphere.
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