Concentration susceptibility in He/sup 3/-He/sup 4/ mixtures near the tricritical point

Thesis/Dissertation · Sun Jan 01 04:00:00 EST 1978

OSTI ID:6165806

Ryschkewitsch, M G

Measurements of the concentration susceptibility chi = deltax/delta..delta../sub T,P/ were made at saturated vapor for six mixtures of He/sup 3/ mole fraction, X, in the range 0.600 < X < 0.677. Particular emphasis was placed on the region near the superfluid transition for three mixtures of X = 0.604, 0.630, 0.664. The method employed measured the vertical concentration gradient induced in a sample by gravity using a high resolution capacitance technique. The predicted peak in chi at the lambda transition was observed but as the tricritical concentration is approached the measurements are severely affected by gravitational rounding. The measurements are compared to other measurements of chi in the same region and to estimates based on extrapolations of calorimetric measurements at smaller mole fractions. In addition, the susceptibilities along paths of constant chemical potential, ..delta.., are calculated. The data are also analyzed in terms of the tricritical scaling scheme of Riedel et al. and are in good agreement with the results of Goellner et al. except very close to the superfluid transition where the older measurements did not resolve the peak in chi. Differences are also noted on the region closest to the tricritical point where our data agree more closely with the measurements of Leiderer et al.

• Research Organization: Duke Univ., Durham, NC (USA)
• OSTI ID: 6165806
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360603* -- Materials-- Properties
CRITICAL PRESSURE
CRITICAL TEMPERATURE
DATA
DISPERSIONS
EVEN-EVEN NUCLEI
EVEN-ODD NUCLEI
EXPERIMENTAL DATA
HELIUM 3
HELIUM 4
HELIUM ISOTOPES
INFORMATION
ISOTOPES
LIGHT NUCLEI
MIXTURES
NUCLEI
NUMERICAL DATA
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
QUANTITY RATIO
STABLE ISOTOPES
THERMODYNAMIC PROPERTIES
TRANSITION TEMPERATURE