REMARKS ON THE ANOMALOUS BEHAVIOR OF ALLOYS CONTAINING TRACES OF MANGANESE OR SIMILAR ELEMENTS

1956 ◽  
Vol 34 (12A) ◽  
pp. 1281-1284 ◽  
Author(s):  
C. J. Gorter ◽  
G. J. van den Berg ◽  
J. de Nobel
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Special Reference ◽  
Hall Effect ◽  
Low Temperatures ◽  
Anomalous Behavior ◽  
Rapid Decrease ◽  
Magnetic Resonances ◽  
Resistance Minimum ◽  
Similar Elements

The anomalous behavior of alloys containing traces of manganese and similar elements is rapidly reviewed as to electrical conductivity, magnetoresistance, susceptibility, magnetic resonances, thermoelectricity, specific heat, thermal conductivity, and Hall effect. Special reference is given to recent data obtained in Leyden. It is argued that, while the rapid decrease of the resistance sometimes occurring at very low temperatures apparently must be attributed to some kind of antiferromagnetic alignment, the resistance minimum, as well as the anomalies in thermoelectricity and the Hall effect, might be due to gaps at the crystalline boundaries.

Hall Effect Measurements on New Thermoelectric Materials

2003 ◽  
Vol 793 ◽  
Author(s):  
Jarrod Short ◽  
Sim Loo ◽  
Sangeeta Lal ◽  
Kuei Fang Hsu ◽  
Eric Quarez ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Hall Effect ◽  
Measurement System ◽  
Material Properties ◽  
Figure Of Merit ◽  
New Materials ◽  
Temperature Dependent ◽  
Additional Insight ◽  
Hall Effect Measurements

ABSTRACTIn the field of thermoelectrics, the figure of merit of new materials is based on the electrical conductivity, thermoelectric power, and thermal conductivity of the sample, however additional insight is gained through knowledge of the carrier concentrations and mobility in the materials. The figure of merit is commonly related to the material properties through the B factor which is directly dependent on the mobility of the carriers as well as the effective mass.To gain additional insight on the new materials of interest for thermoelectric applications, a Hall Effect system has been developed for measuring the temperature dependent carrier concentrations and mobilities. In this paper, the measurement system will be described, and recent results for several new materials will be presented.

scholarly journals Термоэлектрические свойства полуметаллических и полупроводниковых фольг и нитей Bi-=SUB=-1-x-=/SUB=-Sb-=SUB=-x-=/SUB=-

2019 ◽  
Vol 53 (5) ◽  
pp. 664
Author(s):  
А. Николаева ◽  
Л. Конопко ◽  
И. Гергишан ◽  
К. Рогацкий ◽  
П. Стачовик ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Low Temperatures ◽  
Phonon Scattering ◽  
Surface States ◽  
Experimental Investigations ◽  
Quantum Size ◽  
Thermoelectric Energy ◽  
Conductive Surface ◽  
Order Of Magnitude

AbstractThe results of experimental investigations into the thermoelectric properties (electrical conductivity, thermoelectric power, and thermal conductivity) of microtextured foils and single-crystal wires based on semimetal and semiconductor Bi_1 –_ x Sb_ x alloys are presented in the temperature range of 4.2–300 K. It is found that the band gap Δ E in Bi–17 at % Sb wires increases with decreasing wire diameter d , which is a manifestation of the quantum-size effect. At low temperatures ( T < 50 K), in the wires with d < 400 nm, the electrical conductivity increases due to the significant contribution of highly conductive surface states characteristic of topological insulators. It is found for the first time that the thermal conductivity of semimetal Bi–3 at % Sb foils at low temperatures is two orders of magnitude lower, and that of semiconductor Bi–16 at % Sb foils one order of magnitude lower, than that in bulk samples of the corresponding composition due to significant phonon scattering at grain boundaries and surfaces. This effect leads to considerable enhancement of the thermoelectric figure-of-merit ZT and can be used in miniature low-temperature thermoelectric energy converters.

The thermal conductivity of metals

1938 ◽  
Vol 34 (3) ◽  
pp. 474-497 ◽  
Author(s):  
R. E. B. Makinson
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Low Temperatures ◽  
Thermal Equilibrium ◽  
Major Part ◽  
Lattice Energy ◽  
Conduction Electrons ◽  
Electronic Heat ◽  
Lattice Waves ◽  
Lattice Heat

The methods used to measure separately the electronic and lattice heat conductivities κeand κgin a metal are reviewed, and it is pointed out that care is necessary in interpreting the results in view of the underlying assumptions. The equations given by Wilson for κeand for the electrical conductivity σ are used to plot the theoretical values of the electronic Lorentz ratioLe= κe/σTas a function ofT, both for the monovalent metals and for a model metal with 1·8 × 10−2conduction electrons per atom, which is taken to represent bismuth sufficiently accurately for this purpose. Curves for κeand κgas functions ofTare given in both cases, and these, together with a comparison of the observed Lorentz ratio andLe, show that in the monovalent metals κgis unimportant at any temperature, but in bismuth it plays a major part at low temperatures, in agreement with experimental conclusions. Quantitatively the agreement is good for copper and, as far as the calculations go, reasonable for bismuth.Scattering of lattice waves at the boundaries of single crystals (including insulators) at temperatures of a few degrees absolute is shown to be consistent with the experiments of de Haas and Biermasz on KCl and to be responsible for the rise in thermal resistance in this region as suggested by Peierls.The assumption in the theory of electronic heat conduction that the lattice energy distribution function has its thermal equilibrium value is examined in an appendix. The conclusion is that it should be satisfactory, though the proof of this given by Bethe is seen to be inadequate.

The thermal and electrical conductivity of sodium at low temperatures

1951 ◽  
Vol 209 (1098) ◽  
pp. 368-375 ◽  
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Low Temperatures ◽  
Lorenz Curve ◽  
Theoretical Work ◽  
Lattice Vibrations ◽  
Lorenz Number ◽  
Recent Theoretical Work ◽  
Metallic Conduction

Modem theories of metallic conduction, based on the quantum interaction of electrons with the lattice vibrations, predict a considerable variation of Lorenz number with temperature. We have carried out measurements of the thermal and electrical conductivity of two rather pure specimens of sodium continuously from 90 to ~ 4° K and derived an experimental Lorenz curve. Considerable deviations from theory are found; these may in part be due to departure of the lattice vibrations from the Debye spectrum. The thermal conductivity, in particular, is compared with the most recent theoretical work, and the predicted minimum at ~ 0.25Θ has not been found.

scholarly journals The thermal and the electrical conductivity of a copper crystal at various temperatures

1928 ◽  
Vol 121 (788) ◽  
pp. 640-653 ◽  
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Low Temperatures ◽  
Thermal Method ◽  
Copper Crystal

The thermal conductivity of a number of regular and non-regular single metallic crystals has been studied by previous workers. There appear to be no marked differences between the conductivity of single and polycrystal specimens of the regular metals, except at low temperatures, but further confirmation of this statement by additional accurate investigations seems necessary, more particularly at low temperatures, where different observers do not agree. The methods which have been used to determine the thermal conductivity of metals are briefly discussed; the thermal method appears to be the simplest, but the electrical or Kohlrausch's method is better adapted for very low temperatures, i.e ., near 20° K.

scholarly journals The Kinetic Effects, Caused by Thickness Fluctuations of Quantum Semiconductor Wire

2016 ◽  
Vol 17 (1) ◽  
pp. 7-10
Author(s):  
M.A. Ruvinskii ◽  
O.B. Kostyuk ◽  
B.M. Ruvinskii
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Size Effects ◽  
Low Temperatures ◽  
Quantum Wire ◽  
Quantum Size Effects ◽  
One Dimensional ◽  
Quantum Size ◽  
Quantum Semiconductor ◽  
Kinetic Effects

It was theoretically determined the electrical conductivity, thermopower and thermal conductivity of semiconductor quantum wire conditioned by a random field of Gaussian fluctuations of wire thickness. We present the results for cases nondegenerate and generate statistics of carriers. The considered mechanism of relaxation of the carriers is essential for sufficiently thin and clean wire from the А3В5 and А4В6 type of semiconductors at low temperatures. The quantum size effects that are typical of quasi-one-dimensional systems were revealed.

scholarly journals The Thermal and Electrical Conductivity of Copper at Low Temperatures

1953 ◽  
Vol 6 (4) ◽  
pp. 397 ◽  
Author(s):  
GK White
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Low Temperatures

Measurements have been made of the thermal conductivity from 2 to 160 �K and the electrical conductivity from 1�4 to 293 �K of copper in strained and annealed states.

The thermal and electrical conductivity of copper at low temperatures

1952 ◽  
Vol 211 (1104) ◽  
pp. 122-128 ◽  
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Temperature Variation ◽  
Electrical Resistance ◽  
Low Temperatures ◽  
Small Deviation ◽  
Thermal Resistivity ◽  
Lorenz Number

Following previous work on sodium, the thermal and electrical conductivity of copper has been measured continuously between 90 and 2° K . The specimen was of spectrographic purity, and had been found to have a pronounced minimum in the electrical resistance at about 10° K . A similar, but smaller, anomaly was observed in the thermal resistivity with a corresponding small deviation from the Wiedemann-Franz law at the lowest temperatures. As in the case of sodium, marked disagreement with theory was found in the temperature variation both of the thermal conductivity and of the Lorenz number.

Effect of Cu doping on the electrical Properties of ZnTe by Vacuum Thermal Evaporation

2018 ◽  
Vol 31 (3) ◽  
pp. 20
Author(s):  
Sarmad M. M. Ali ◽  
Alia A.A. Shehab ◽  
Samir A. Maki
Keyword(s):  
Activation Energy ◽  
Electrical Conductivity ◽  
Hall Effect ◽  
Carrier Concentration ◽  
Hall Mobility ◽  
Cu Doping ◽  
Before And After ◽  
Hall Effect Measurements ◽  
Evaporation Technique ◽  
P Type

In this study, the ZnTe thin films were deposited on a glass substrate at a thickness of 400nm using vacuum evaporation technique (2×10-5mbar) at RT. Electrical conductivity and Hall effect measurements have been investigated as a function of variation of the doping ratios (3,5,7%) of the Cu element on the thin ZnTe films. The temperature range of (25-200°C) is to record the electrical conductivity values. The results of the films have two types of transport mechanisms of free carriers with two values of activation energy (Ea1, Ea2), expect 3% Cu. The activation energy (Ea1) increased from 29meV to 157meV before and after doping (Cu at 5%) respectively. The results of Hall effect measurements of ZnTe , ZnTe:Cu films show that all films were (p-type), the carrier concentration (1.1×1020 m-3) , Hall mobility (0.464m2/V.s) for pure ZnTe film, increases the carrier concentration (6.3×1021m-3) Hall mobility (2m2/V.s) for doping (Cu at 3%) film, but  decreases by increasing Cu concentration.

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