STUDY OF CLUSTERS IN Pb DOPED KCl SINGLE CRYSTALS BY THERMAL CONDUCTIVITY MEASUREMENTS AT LOW AND VERY LOW TEMPERATURES

Thermal conductivity measurements have been made upon a series of lead specimens between 1 and 4° K, in the superconducting and in the normal states. Both single crystals and polycrystals were studied, and also specimens containing various added impurities. The results in the superconducting state confirm the hypothesis that below about 1·4° K the thermal current is carried entirely by lattice waves, and that these are not scattered by conduction electrons. This conclusion is based upon three pieces of evidence: (1) the thermal conductivity K s is insensitive to the amount and species of impurity; (2) it depends upon the geometry of the specimen for sufficiently thin specimens; (3) it is sensitive to plastic deformation, which can be explained if the lattice waves are scattered by dislocations. A brief discussion is given of the possible significance of these results in the theory of superconductivity.

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Thermal Conductivity of Manganese Ferrite Single Crystals at Low Temperatures

Japanese Journal of Applied Physics ◽

10.1143/jjap.5.455 ◽

1966 ◽

Vol 5 (5) ◽

pp. 455-455 ◽

Cited By ~ 4

Author(s):

Yasutaka Suemune

Keyword(s):

Thermal Conductivity ◽

Single Crystals ◽

Low Temperatures ◽

Manganese Ferrite

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Thermal Conductivity of Single-Crystal and Sintered RBa2Cu3O7 at low Temperatures

MRS Proceedings ◽

10.1557/proc-99-745 ◽

1987 ◽

Vol 99 ◽

Cited By ~ 5

Author(s):

J. E. Graebner ◽

L. F. Schneemeyer ◽

R. J. Cava ◽

J. V. Waszczak ◽

E. A. Rietman

Keyword(s):

Thermal Conductivity ◽

Particle Size ◽

Single Crystals ◽

Free Path ◽

Low Temperatures ◽

Rayleigh Scattering ◽

Resonant Scattering ◽

Sintered Sample ◽

Mean Free Path ◽

Strong Scattering

ABSTRACTThe thermal conductivity k of micro-twinned single crystals of YBa2Cu3O7 and HoBa2Cu3O7 and a sintered sample of YBa2Cu3O7 has been measured for temperatures 0.03<T<5K. For the single crystals, k is small and varies as T1.8-1.9 This behavior resembles k for glassy insulators except for the lack of a plateau above IK. It is concluded that the thermal carriers are phonons with their mean free path limited by resonant scattering from tunneling entities, as in glasses. Suggestions for the location of tunneling systems are given. For the sinter, k is still smaller but does not follow a power law T-dependence. It is similar to other sintered ceramics with the same particle size, where the phonon mean free path is dominated by Rayleigh scattering from the particles. This strong scattering from the microstructure presumably masks the scattering from TS within each particle.

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Lattice Thermal Conductivity of Germanium-Silicon Alloy Single Crystals at Low Temperatures

Physical Review ◽

10.1103/physrev.122.450 ◽

1961 ◽

Vol 122 (2) ◽

pp. 450-458 ◽

Cited By ~ 60

Author(s):

Arnold M. Toxen

Keyword(s):

Thermal Conductivity ◽

Single Crystals ◽

Low Temperatures ◽

Lattice Thermal Conductivity ◽

Silicon Alloy ◽

Germanium Silicon

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The thermal conductivity of solid helium

Proceedings of the Royal Society of London Series A - Mathematical and Physical Sciences ◽

10.1098/rspa.1952.0188 ◽

1952 ◽

Vol 214 (1119) ◽

pp. 546-563 ◽

Cited By ~ 41

Keyword(s):

Thermal Conductivity ◽

Thermal Resistance ◽

Single Crystals ◽

Liquid Helium ◽

Solid Helium ◽

Boundary Scattering ◽

Conductivity Measurements ◽

Helium Ii ◽

Characteristic Temperatures ◽

Thermal Conductivities

The thermal conductivities of crystals of solid helium at densities between 0⋅194 and 0⋅218 g/cm 3 have been measured at liquid-helium temperatures. In order to interpret the results, the specific heat of solid helium at these densities has been measured from 0⋅6 to 1⋅4° K. The range of densities employed is sufficient to allow the observation of Debye characteristic temperatures varying by 40 %, and of thermal conductivities varying by factors of over 10. It is shown that the conductivity measurements are in accord with the ‘umklapp’ type of thermal resistance derived by Peierls (1929, 1935). Further work was restricted by the difficulty of obtaining good single crystals in narrow tubes, but measurements of the conductivity at one density were obtained down to 0⋅3° K. In this region the conductivity is limited by boundary scattering and is higher than that observed by other authors for liquid helium II at similar temperatures.

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