The influence of silica nano-inclusions on the structure of methane crystal observed in thermal conductivity experiment

Nikonkov, R. V.; Stachowiak, P.; Jeżowski, A.; Кривчиков, А. И.

doi:10.1016/j.ijheatmasstransfer.2017.05.014

Cited by 4 publications

(1 citation statement)

References 22 publications

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“…In recent years, considerable attention of researchers has been attracted to new complex systems which, though not being amorphous materials, exhibit glass-like thermal properties (the so-called glassy crystals). [1] Such materials include solid alcohols, [2,3] clathrates, [4,5] ferroelectric relaxors (single crystals and ceramics), [6,7] cryocrystal nanocomposite, [8,9] and thermoelectrcs. [10][11][12] Manifestation of glass-like thermal properties in systems of different nature calls for new theoretical models able to explain both their similarities and differences in a unified approach.…”

Section: Introductionmentioning

confidence: 99%

Thermal conductivity of systems with a gap in the phonon spectrum

Salamatov

2018

Chinese Phys. B

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An original theoretical model for describing the low-temperature thermal conductivity in systems with a region of forbidden values (a gap) in the phonon spectrum is proposed. The model is based on new experimental results on the temperature dependence of the phonon diffusion coefficient in nanoceramics and dielectric glasses which showed a similar anomalous behavior of the diffusion coefficient in these systems that may be described under the assumption of a gap in the phonon spectrum. In this paper, the role of the gap in low-temperature behavior of the thermal conductivity, κ(T ), is analyzed. The plateau in the temperature dependence of the thermal conductivity is shown to correlate with the position and the width of the gap. The temperature dependence of thermal conductivity of such systems when changing the scattering parameters related to various mechanisms is studied. It is found that the umklapp process (U-processes) involving low-frequency short-wavelength phonons below the gap forms the behavior of the temperature dependence of thermal conductivity in the plateau region. A comparison of the calculated and experimental results shows considerable possibilities of the model in describing the low-temperature thermal conductivity in glass-like systems.

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Section: Introductionmentioning

confidence: 99%

Thermal conductivity of systems with a gap in the phonon spectrum

Salamatov

2018

Chinese Phys. B

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Experimental setup for thermal conductivity investigation of amorphous materials

2022

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Heat transport in methane-palladium nanocomposites

Nikonkov

Stachowiak

Jeżowski

2020

Low Temperature Physics

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The thermal conductivity of crystalline methane samples with spherical palladium nanoparticles of diameter 6, 8, 10, 12, 18 and 24 nm embedded in the CH4 structure was determined in the temperature range 2–35 K. The spherical nanoparticles featured a low dispersion of the sphere diameter and the volume fraction of the nanoparticles in the nanocomposites amounted to 0.15. Time relaxation approximation analysis shows that the matrix resistive phonon scattering processes are dominated by diffuse scattering of phonons by matrix-nanoparticle boundaries. Other considered intensities of resistive scattering mechanisms of phonons, i.e., scattering by point defects, by dislocation strain fields and by phonons in U-processes remain almost the same in nanocomposites and pure methane crystal. In transfer of the heat through the investigated nanocomposites non-resistive scattering of phonons by the nanoparticles, such as phonon specular scattering and multiple scattering of phonons show very high intensity. The nanocomposites formed of 18 and 24 nm nanospheres show anomalous power increase of the thermal conductivity coefficient dependence on temperature, exceeding the values known for a typical dielectric crystal.

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The influence of silica nano-inclusions on the structure of methane crystal observed in thermal conductivity experiment

Cited by 4 publications

References 22 publications

Thermal conductivity of systems with a gap in the phonon spectrum

Thermal conductivity of systems with a gap in the phonon spectrum

Experimental setup for thermal conductivity investigation of amorphous materials

Heat transport in methane-palladium nanocomposites

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