کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1811529 1025597 2011 6 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Homogeneous 3He-4He solid solutions in the pre-separation region
موضوعات مرتبط
مهندسی و علوم پایه فیزیک و نجوم فیزیک ماده چگال
پیش نمایش صفحه اول مقاله
Homogeneous 3He-4He solid solutions in the pre-separation region
چکیده انگلیسی
Temperature dependences of the pressure P(T) in homogeneous solid 3He-4He mixtures have been studied experimentally in the wide range of concentrations (35.0%, 62.0%, 68.3%, 74.1%, 75.0%, and 89.3% 3He) above and below the equilibrium phase separation temperature Ts. An anomalous behaviour of the pressure in the vicinity of Ts is found for all investigated samples. With decreasing temperature, as Ts is approached, the pressure increases instead of expected reduction due to decrease in the phonon contribution (Pph∼T4). Such an increase in pressure continues in the metastable region below Ts until the mixture separates. Theoretical interpretation of the observed effects based on a rigorous thermodynamic approach is proposed. The found experimentally pressure behaviour can be described only with the consistent account for fluctuations in the impurity subsystem which near Ts dominates over phonon contribution into the pressure. The obtained theoretical results are in good quantitative agreement with the experimental data. Density fluctuations in the concentrated mixtures give rise to a spontaneous formation of impuriton nano-clusters containing several hundreds of atoms. The fluctuation can be rigorously interpreted as a nucleus of the second phase in the pre-separated homogeneous solid mixture. The estimated size of the fluctuation nano-clusters agrees with the corresponding value for second phase nuclei obtained from the Lifshits-Slesov phenomenological theory of homogeneous nucleation.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Physica B: Condensed Matter - Volume 406, Issue 20, 15 October 2011, Pages 3870-3875
نویسندگان
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