CRITICAL PROPERTIES OF HE-4 IN AEROGEL NEAR THE LAMBDA-LINE

被引:6
作者
LARSON, M [1 ]
MULDERS, N [1 ]
MEHROTRA, R [1 ]
GOLDNER, LS [1 ]
AHLERS, G [1 ]
机构
[1] UNIV CALIF SANTA BARBARA,CTR NONLINEAR SCI,SANTA BARBARA,CA 93106
关键词
D O I
10.1007/BF00692580
中图分类号
O59 [应用物理学];
学科分类号
摘要
We measured the superfluid fraction rho(S)/rho and the isobaric thermal expansion coefficient beta(P) of He-4 confined in an aerogel. Data were obtained near the lambda-line along several isobars. Powerlaw fits to the results for rho(S)/rho as a function of t = T/T(c) - 1 (T(c) is the transition temperature) give a pressure--independent exponent zeta = 0.755 when a confluent singular term is included. Fits to the beta(P) data of power laws yield the specific-heat exponents alpha = -0.6 and alpha' congruent-to -1.0 not-equal alpha above and below T(c) respectively. When an analytic background term a x t is included in the fit, the pressure-independent value alpha = alpha'= -0.59 is permitted, but the amplitude ratio A'/A is found to be near zero and the coefficient of the analytic term is large. The measured values for zeta and alpha' or alpha are inconsistent with hyperscaling in three dimensions.
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页码:79 / 89
页数:11
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