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Thermal conductivit...
Abstract
Ämnesord
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- We have measured the thermal conductivity κ and the thermal diffusivity a of a dense bulk ceramic polycrystalline sample of YBa2Cu4O8 (1:2:4) in the temperature range 30–300 K. We find κ≊10 W m-1 K-1 at 100 K, significantly higher than in ceramic YBa2Cu3O7-δ (1:2:3) and approaching the in-plane value for single-crystal 1:2:3, and decreasing to 7.6 W m-1 K-1 at 300 K. The data for this sample can be described by standard theories for phonon thermal conductivity of crystalline materials with boundary, phonon, and electron scattering. The higher κ in 1:2:4 as compared to 1:2:3 is, in this model, due to the smaller point defect scattering in the former. The fitted parameters for the three scattering mechanisms all agree with independent estimates based on simple models; inserting data for electric resistivity, grain size, carrier density, and lattice properties we can predict κ and its T dependence to within about 20%. We also discuss models for the phonon and electron thermal conductivities in some detail, including some second-order effects such as inelastic electron scattering and a T-dependent carrier density.
Ämnesord
- NATURVETENSKAP -- Fysik -- Den kondenserade materiens fysik (hsv//swe)
- NATURAL SCIENCES -- Physical Sciences -- Condensed Matter Physics (hsv//eng)
- TEKNIK OCH TEKNOLOGIER -- Materialteknik -- Annan materialteknik (hsv//swe)
- ENGINEERING AND TECHNOLOGY -- Materials Engineering -- Other Materials Engineering (hsv//eng)
Nyckelord
- Thermal conductivity
- superconductor
- ceramic
- high transition temperature
- electronic conduction
- lattice conduction
- electron-phonon interaction
- phonon-phonon interaction
- YBa2Cu4O8
- Condensed matter physics
- Kondenserade materiens fysik
- fysik
- Physics
- Materialteknik
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