THE UNIVERSALITY TEST OF α AND α' FOR 3He/4He MIXING SYSTEM NEAR THE LAMBDA TRANSITION

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THE UNIVERSALITY TEST OF α AND α’ FOR 3He/4He MIXING SYSTEM NEAR THE LAMBDA

TRANSITION

T. Takada, T. Watanabe

To cite this version:

T. Takada, T. Watanabe. THE UNIVERSALITY TEST OF α AND α’ FOR 3He/4He MIXING

SYSTEM NEAR THE LAMBDA TRANSITION. Journal de Physique Colloques, 1978, 39 (C6),

pp.C6-190-C6-191. �10.1051/jphyscol:1978684�. �jpa-00218364�

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JOURNAL DE PHYSIQUE Colloque C6, supplkment au no 8, Tome 39, aolit 1978, page C6-190

THE U N I V E R S A L I T Y T E S T OF a AND a' FOR 3 ~ e / 4 ~ e M I X I N G SYSTEM NEAR THE LAMBDA T R A N S I T I O N

T. Takada and T. Watanabe

Hokkaido University, Department o f Phgsics, Japan

RLsum6.- Nous avons mesure la chaleur splcifique-des mllanges '~e/'He, x = 0,070 _;0,129 _;0,245 _; 0,328 dans 1' intervalle 3 x 10 "K 5

IT - ~~1

^<I0'K. NOS valeurs expdrimentales de l'exposant cri- tique a le long de la courbe 5 difference de potentiel chimique constant sont independantes de x.

cp

Abstract.- The specific heat under saturated vapour pressure of 3 ~ e / 4 ~ e mixtures with 3 ~ e mole fraction x = 0.070, 0.129, 0.245L 0.328 has been measured near the h transition in the temperature range, 3 x 10 6~ 5

IT -

^T

I

< 10 2 ~ . The critical exponent 'a along the path of constant chemical potential difference was hound to be independent of x.

The universality of a and a' of pressure ef- in table I.

fect for 'He was reported by H. Okaji and one of au-

thors. In that report, the values of a and a' do not The specific heat measurements of x = 0.440, deviate from the constant in the temperature range 0.500, 0.550 and 0.600 3 ~ e content are carrying out between IO-'K <_

IT -

^T

1

<IO-'K, up to about 27.66

X and these analytical results are reported at the

bar /I/. present conference.

In the present report, the experimental re- sult of specific heat of 3 ~ e / 4 ~ e mixing system under the saturated vapour pressure is reported. The experimental temperature range is in

3x10-'~ 5

IT -

<10-*K and the 3 ~ e mole fractions are x = 0.070, 0.129, 0.245 and 0.328. Cryostat and a.c. bridge circuit for specific heat measurement is similar in the previous report /I/. The temperature resolution of this cryostal and bridge circuit as-

sembly is in

-

I O - ~ K to power of 5 ~ 1 0 - ~ e r ~ / s and the Fig. 1 : Critical exponent a as a function of 3 ~ e .mole fraction. Small symbolsXindicate the results stability of this circuit is in 5xl0-'~/hour. of Gasparini et al. 121.

When the next expression is assumed along the path of x = constant, the results of critical exponent a and a' are shown in figure 1. a and a' vary

X X X X

linearly with x.

A;

- 4 -

C PX ECLt(t 1) + B; t

-171

In the second step, the next expression is applied along the path of I$ = ~ 3 - ~= 4constant.

A '

C*(I$~) = z(t-a'

-

¹) + Bi

In above expression a;, A; and B' is derived from

. . 6

the thermodynamical relation 121; The results of a cp and a' is given in figure 2. The values of a and

cp cp

a' are constant in the range of x

2

0.328. The pre- cp

sent results agree well with the results of Gaspari- ni 121. The results of A;

,

Bi, A' and B' are given

cp cp

Fig. 2 : Critical exponent a as a function of 3 ~ e mole fraction. Small symbols'indicate the results of Gasparini et al. 121.

Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphyscol:1978684

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Table I

Power-law parameters. Parenthesis indicate the parameter below T

X'

The unit of A and B is Sfmole K.

References

/ I / Okaji, H., and Watanabe, T., S . Low Temp. Phys.

32 (1978) in press

-

/2/ Gasparini, M.F., and Moldover, R.M.. Phys. Rev.

B12 (1975) 93