Abstract
The heat capacity of pure in low density aerogel is measured at 22.5 bars. The superfluid response is simultaneously monitored with a torsional oscillator. A slightly rounded heat capacity peak, in width, is observed at the -aerogel superfluid transition, . Subtracting the bulk contribution, the heat capacity shows a Fermi-liquid form above . We can fit the heat capacity attributed to superfluid within the aerogel with a rounded BCS form accounting for 0.30 of the nonbulk fluid in the aerogel, or by assuming a substantial reduction in the superfluid order parameter. Both approaches are consistent with earlier superfluid density measurements.
- Received 2 May 2002
DOI:https://doi.org/10.1103/PhysRevLett.89.115301
©2002 American Physical Society