Abstract
Using fourth-sound techniques, we have measured the depression of the superfluid fraction of confined in small pores of packed powder over wide temperature () and pressure ( bars) ranges. From the analysis of the data we determine the magnitude and the pressure dependence of the healing length. The healing length decreases from 520 Å at 0.5 bar to 200 Å at 20 bars. The values are in fair agreement with those expected from the BCS expression.
- Received 29 December 1986
DOI:https://doi.org/10.1103/PhysRevLett.58.1949
©1987 American Physical Society