Finite-geometry effects, superfluid density, and universality in $sup 3$He-- $sup 4$He mixtures near the superfluid transition

Journal Article · Sun Jun 01 04:00:00 EDT 1975 · Phys. Rev., B, v. 11, no. 11, pp. 4292-4303

OSTI ID:4169783

Thomlinson, W C; Ihas, G G; Pobell, F

The amplitude and velocity of second sound near T/sub lambda/ were measured in $sup 3$He--$sup 4$He mixtures with molar $sup 3$He concentrations X = 0.0000, 0.096, 0.204, 0.396, and 0.555. The sound was generated and detected in resonators equipped with superleak transducers with channel sizes d = 0.2 $mu$m and d = 0.6 $mu$m. The onset temperatures T$sub 0$(X) for superfluidity were determined by observing the vanishing of the second-sound amplitude at temperatures below T/sub lambda/(X). The reduced shift, epsilon$sub 0$ = 1 -- T$sub 0$(X)/T/sub lambda/(X), of the onset temperature T$sub 0$ increases by about a factor of 6 for X = 0 to X = 0.4. The critical exponents in the equations epsilon$sub 0$ = (d/d*)$sup -$/sup lambda/' and l = l*epsilon$sup -$/ sup nu/' are independent of X to within 3 percent (l is the onset length for superfluidity). In addition, the quantity l rho/sub s//T is found to be independent of concentration in agreement with theoretical predictions. For the superfluid fraction, rho/sub s//rho = k epsilon/sup zeta/, it is found that the exponent zeta is nearly concentration independent for X = 0.0 to 0.4, whereas the amplitude k decreases by almost an order of magnitude. (12 figures) (auth)

• Research Organization: Inst. fuer Festkoerperforschung, Kernforschungsanlage, Juelich, Ger.
• NSA Number: NSA-33-006319
• OSTI ID: 4169783
• Journal Information: Phys. Rev., B, v. 11, no. 11, pp. 4292-4303, Journal Name: Phys. Rev., B, v. 11, no. 11, pp. 4292-4303; ISSN PLRBA
• Country of Publication: United States
• Language: English

Related Subjects

*HELIUM II
640700*
BINARY MIXTURES
CHEMICAL COMPOSITION
HELIUM 3
HELIUM 4
N62100* --Physics (Fluid)--Electrofluid Mechanics
QUANTITY RATIO
SECOND SOUND
SUPERFLUIDITY
TRANSITION TEMPERATURE