Thermal and Electrical Conductivities of Sodium from 40 to 360 K

1972 ◽  
Vol 50 (12) ◽  
pp. 1386-1401 ◽  
Author(s):  
J. G. Cook ◽  
M. P. Van der Meer ◽  
M. J. Laubitz
Keyword(s):  
Thermal Conductivity ◽  
Electrical Resistivity ◽  
Low Temperatures ◽  
Characteristic Temperature ◽  
Published Data ◽  
Inelastic Electron ◽  
Conductivity Data ◽  
Electron Collisions ◽  
Electrical Conductivities ◽  
Flow Apparatus

We present data on the electrical and thermal resistivities and the thermopower of three pure Na specimens from 40 to 360 K. The measurements were made using a guarded longitudinal heat flow apparatus that had previously been calibrated with Au and Al. The specimens were placed in a vacuum environment using no solid inert liner.The electrical resistivity data indicate ΘR = 194 K. The thermal conductivity data show a 4% minimum near 70 K and an ice point value of 1.420 W/cm K. The reduced Lorenz function L/L0 agrees with published data at low temperatures but above 300 K levels off at approximately 0.91. On the basis of published data for liquid Na, L/L0 does not change by more than 3% at the melting point.The minimum in the thermal conductivity and a part of the high temperature deviations of L from L0 are tentatively ascribed to inelastic electron–phonon collisions having a characteristic temperature near that of longitudinal phonons. The possibility that electron–electron collisions further depress L at high temperatures is critically examined.

THERMAL AND ELECTRICAL CONDUCTIVITY OF RHODIUM, IRIDIUM, AND PLATINUM

1957 ◽  
Vol 35 (3) ◽  
pp. 248-257 ◽  
Author(s):  
G. K. White ◽  
S. B. Woods
Keyword(s):  
Electrical Conductivity ◽  
Electrical Resistivity ◽  
High Purity ◽  
Low Temperatures ◽  
Rapid Rate ◽  
Transition Elements ◽  
Electron Collisions ◽  
Electrical Conductivities ◽  
Electrical Resistivities ◽  
The Ideal

Measurements are reported of the thermal and electrical conductivities of the transition elements Rh, Ir, Pt in a state of high purity; the rapid rate of decrease of the "ideal" thermal and electrical resistivities with temperature, particularly in Rh and Ir, suggests that s–d transitions are not a dominant resistive mechanism at low temperatures in these metals, in contrast to palladium, iron, and nickel, which were studied previously. The electrical resistivity of platinum is in general agreement with the earlier results of de Haas and de Boer (1934); the quadratic dependence on temperature observed below about 10° K. suggests that electron–electron collisions may well be an important factor in this metal.

Thermal conductivity and electrical resistivity of NbTi alloys at low temperatures

Cryogenics ◽  
1981 ◽  
Vol 21 (12) ◽  
pp. 741-745 ◽  
Author(s):  
Yu.F. Bychkov ◽  
R. Herzog ◽  
I.S. Khukhareva
Keyword(s):  
Thermal Conductivity ◽  
Electrical Resistivity ◽  
Low Temperatures ◽  
Ti Alloys

THERMAL AND ELECTRICAL CONDUCTIVITIES OF SOLIDS AT LOW TEMPERATURES

1955 ◽  
Vol 33 (2) ◽  
pp. 58-73 ◽  
Author(s):  
Guy K. White ◽  
S. B. Woods
Keyword(s):  
Thermal Conductivity ◽  
Low Temperatures ◽  
Lattice Thermal Conductivity ◽  
Copper Alloys ◽  
Electrical Conductivities

An apparatus for measuring the thermal and electrical conductivities of solids at temperatures between 2° and 300°K. is described. Results are presented of measurements of some dilute copper alloys, beryllium, bismuth, and germanium. Where possible the lattice thermal conductivity has been deduced, directly or indirectly from the measurements, and its magnitude and variation with temperature are discussed with relation to theory.

Thermal and Electrical Conductivities of Carbon Fibers and Carbon Nanotubes Incorporated Polyurethanes Composites

2010 ◽  
Vol 442 ◽  
pp. 349-355 ◽  
Author(s):  
Shahrul A. Abdullah ◽  
Lars Frormann ◽  
Anjum Saleem
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Electrical Resistivity ◽  
Carbon Fibers ◽  
Polymer Matrix ◽  
Filler Concentration ◽  
Melt Mixing ◽  
Electrical Conductivities ◽  
The Matrix ◽  
Polyurethane Composites

Single filler polyurethane composites with carbon fibers (CFs) and multi-walled carbon nanotubes (MWNTs) were prepared by melt mixing methods and its thermal as well as electrical resistivity characteristics were investigated. The influences of fillers and mixing methods on thermal and electrical conductivity of CF/- and MWNT/polyurethane composites were investigated and the result shows that the addition of carbon fillers improved the thermal conductivity of the polyurethane composites. Higher filler concentration results in better thermal conductivity because better formation of thermally conductive networks along polymer matrix to ensure the thermal was conducted through the matrix and the network along the polymer composites. The presence of carbon additives improves the electrical resistivity of the materials as well. The present study revealed the potential of carbon as agent for better thermal and electrical conductivities and their properties depend strongly on the dispersion and distribution of the fillers in the polymer matrix.

Performance of Nanoscale Quantum Well Thermoelectrics

2007 ◽  
Author(s):  
Daniel Krommenhoek ◽  
Norbert Elsner ◽  
Saeid Ghamaty ◽  
Velimir Jovanovic
Keyword(s):  
Thermal Conductivity ◽  
Power Generation ◽  
Electrical Resistivity ◽  
Seebeck Coefficient ◽  
Thermoelectric Materials ◽  
Thermoelectric Module ◽  
Conductivity Data ◽  
Resistivity Data ◽  
P Type ◽  
Bulk Thermal Conductivity

Alternating 10 nm thermoelectric films of N-type Si/SiGe and P-type Si/SiGe and B4C/B9C have been fabricated on various substrates, electrically joined and thermoelectric properties measured from 40°K up to 700°K. These nanoscale thermoelectric films demonstrate excellent thermoelectric power factors significantly higher than current bulk thermoelectric materials. The implications of the measured thermoelectric Seebeck coefficient data and electrical resistivity data for alternating 10 nm films that are grown to thicknesses of one to 10 microns means efficiencies of 15% at 200°C temperature differences and efficiencies of 30% at 400°C temperature differences. Utilizing Seebeck and resistivity data obtained by Hi-Z and UCSD, along with published bulk thermal conductivity data, which is conservative, unique thermoelectric module and generator concept designs for both power generation and cooling are presented over wide temperature and power ranges.

The electrical resistivity of gallium and some other anisotropic properties of this metal

1951 ◽  
Vol 209 (1099) ◽  
pp. 525-541 ◽  
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Electrical Resistivity ◽  
Single Crystals ◽  
Anisotropic Properties ◽  
Electrical Conductivities ◽  
Expansion Coefficients

It is shown that single crystals of gallium can be produced with considerable ease, and that these crystals show greater anisotropism in their conducting properties than those of other metals. At normal temperatures the electrical conductivities for the three axial directions c : a : b are in the ratio 1:3.2:7, and the expansion coefficients are in the ratio 1:0.7:1.9. Results are given showing that these ratios persist down to —180° C with relatively little change. From preliminary observations at normal temperature it seems that the thermal conductivity varies much as does the electrical conductivity and that the mechanical properties will also prove to be markedly anisotropic.

scholarly journals The thermal and electrical resistance of bismuth single crystals. The effects of temperature and magnetic fields

1939 ◽  
Vol 170 (943) ◽  
pp. 561-583 ◽  
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Magnetic Fields ◽  
Single Crystals ◽  
Preliminary Investigation ◽  
National Physical Laboratory ◽  
Transverse Magnetic ◽  
Published Data ◽  
Physical Laboratory ◽  
Electrical Conductivities

The anomalous physical properties of bismuth, particularly as regards the reduction of the thermal and electrical conductivities in magnetic fields, have claimed the attention of a number of workers in the past. Most of the published data refers to the electrical conductivity, owing, no doubt, to the greater ease of measurement; and but little reliable work appears to have been done on the thermal conductivity, at any rate in the case of single crystals. Lounds (1902) carried out thermal-conductivity measurements employing magnetic fields up to about 5000 gauss, but the accuracy of his results was prescribed by the limitations of the method and the smallness of his crystals. Kapitza (1928) undertook an extensive investigation on the electrical conductivity of single crystals using very intense momentary fields. Banta (1932) published thermal-conductivity values using fields up to 8000 gauss, while more recently de Haas and Capel (1934) have made thermal measurements, in the absence of a field, at liquid-air and liquid-hydrogen temperatures. The results of a preliminary investigation (Kaye and Higgins 1929 a ) at the National Physical Laboratory on the change in thermal conductivity of bismuth single crystals in transverse magnetic fields were published in 1929. In this work, specimens, which were cut in the form of disks 25 mm. in diameter and 2 mm. thick from a large crystal grown by Bridgman’s method (1925), were tested in a “plate” type of apparatus, field strengths up to 11,000 gauss being employed in a 38 mm. air gap.

Electrical Resistivity, Thermal Conductivity and Magnetic Susceptibility of Polycrystalline Samarium at Low Temperatures

1966 ◽  
Vol 21 (11) ◽  
pp. 1856-1859 ◽  
Author(s):  
Sigurds Arajs ◽  
G. R. Dunmyre
Keyword(s):  
Thermal Conductivity ◽  
Electrical Resistivity ◽  
Magnetic Susceptibility ◽  
Magnetic Moment ◽  
Low Temperatures ◽  
Fair Agreement ◽  
Magnetic Transformation ◽  
Electronic Thermal Conductivity ◽  
Theoretical Considerations

Electrical resistivity, thermal conductivity, and magnetic susceptibility have been measured, using the same sample of samarium, from 4 to 300 °K, from 5 to 200 °K, and from 4 to 300 °K, respectively. Two anomalies, one at 12 ± 1 °K and another at 106 ± 1 °K, are observed, resulting from an order-order magnetic transformation and an antiferromagnetic-paramagnetic transition, respectively. The Lorenz function is found to be larger at any temperature than that expected for pure electronic thermal conductivity. This implies that there is some phonon and possibly also some magnon thermal conductivity in samarium at low temperatures. The magnetic moment disorder electrical resistivity of samarium is determined to be 39.0 ± 0.5 μΩ cm, in fair agreement with the value to be expected from theoretical considerations.

Sign in / Sign up

Export Citation Format

Share Document