Damping of second sound near the superfluid transition of /sup 4/He as a function of pressure

Journal Article · Thu Nov 01 04:00:00 EST 1984 · Phys. Rev. B: Condens. Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.30.5116· OSTI ID:6235556

Mehrotra, R; Ahlers, G

Quantitative experimental results of the second-sound damping D/sub 2/ near the superfluid transition temperature T/sub lambda/(P) are presented at several pressures P as a function of the reduced temperature t = 1-T/T/sub lambda/(P). The data cover the entire pressure range of the transition and are for 2 x 10/sup -5/< or approx. =t< or approx. =0.1. Their experimental uncertainty is in the range of 2--4 %. The experimental technique used in this work is described in detail. It is based on a tone-burst method and includes a number of novel features such as discrimination against higher harmonics by spectral analysis of the pulses, rectification before signal averaging to avoid the detrimental effect of temperature noise, a careful study of finite-amplitude effects, and quantitative corrections for nonparallelism of the cavity ends. The results are compared with the predictions based on renormalization-group theory and thermal-conductivity measurements above T/sub lambda/. The intricate pressure dependence of the data, which changes sign near troughly-equal10/sup -3/, is given rather well by the prediction. However, the details of the temperature dependence of the data at a given pressure disagree with the theory in its present form by deviations somewhat greater than the experimental uncertainty.

• Research Organization: Department of Physics, University of California, Santa Barbara, California 93106
• OSTI ID: 6235556
• Journal Information: Phys. Rev. B: Condens. Matter; (United States), Journal Name: Phys. Rev. B: Condens. Matter; (United States) Vol. 30:9; ISSN PRBMD
• Country of Publication: United States
• Language: English

Related Subjects

640450* -- Fluid Physics-- Superfluidity
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
DAMPING
DISCRIMINATORS
ELECTRONIC CIRCUITS
ELECTRONIC EQUIPMENT
EQUIPMENT
EVEN-EVEN NUCLEI
FLUIDS
HARMONICS
HELIUM 4
HELIUM II
HELIUM ISOTOPES
ISOTOPES
LAMBDA POINT
LIGHT NUCLEI
NUCLEI
OSCILLATIONS
PHYSICAL PROPERTIES
PRESSURE DEPENDENCE
PULSE ANALYZERS
QUANTUM FLUIDS
SECOND SOUND
STABLE ISOTOPES
SUPERFLUIDITY
THERMAL CONDUCTIVITY
THERMODYNAMIC PROPERTIES
TRANSITION TEMPERATURE