Thermal conductivity of YBa2Cu4O8 dominated by phonon-phonon interactions

• The thermal conductivity κ of dense sintered ceramic YBa2Cu4O8 in the range 30–310 K has been measured. At 100 K, κ is 10 W m-1 K-1, approaching the in-plane κ of single crystals of other high-Tc materials. κ decreases rapidly with increasing T to 7.4 W m-1 K-1 at 300 K. Fitting standard models for κ(T) to the data we find that κ is limited mainly by phonon-phonon interactions. Depending on the model used, the best fit is found for effective values of FTHETADebye between 155 and 185 K, characteristic for the acoustic phonon branches, indicating that such phonons carry most of the heat. Finally, we suggest a possible way to test the electron-phonon model for the electrical and thermal conductivities in high-Tc materials.

Ämnesord

NATURVETENSKAP  -- Fysik -- Den kondenserade materiens fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Condensed Matter Physics (hsv//eng)

Nyckelord

Superconductivity

thermal conductivity

YBa2Cu4O8

1-2-4

High transition temperature superconductors

HiTc

HTS

phonon-phonon interactions

vacancy scattering

Condensed matter physics

Kondenserade materiens fysik

Superconductivity

Supraledning

fysik

Physics

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