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 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.

LOW TEMPERATURE RESISTIVITY OF TRANSITION ELEMENTS: VANADIUM, NIOBIUM, AND HAFNIUM

1957 ◽  
Vol 35 (8) ◽  
pp. 892-900 ◽  
Author(s):  
G. K. White ◽  
S. B. Woods
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Electrical Resistivity ◽  
Electrical Resistance ◽  
Thermal Resistivity ◽  
Superconducting Transition ◽  
Transition Elements ◽  
Pure Niobium ◽  
Temperature Resistivity ◽  
The Ideal

Measurements of the thermal conductivity from 2° to 90 ° K. and electrical conductivity from 2° to 300 ° K. are reported for vanadium, niobium, and hafnium. Although the vanadium and hafnium are not as pure as we might wish, measurements on these metals and on niobium allow a tabulation of the "ideal" electrical resistivity clue to thermal scattering for these elements from 300 ° K. down to about 20 ° K. Ice-point values of the "ideal" electrical resistivity are 18.3 μΩ-cm. for vanadium, 13.5 μΩ-cm. for niobium, and 29.4 μΩ-cm. for hafnium. Values for the "ideal" thermal resistivity of vanadium and niobium are deduced from the experimental results although for vanadium and more particularly for hafnium, higher purity specimens are required before a very reliable study of "ideal" thermal resistivity can be made. For the highly ductile pure niobium, the superconducting transition temperature, as determined from electrical resistance, appears to be close to 9.2 ° K.

Electrical Conductivity and Thermogravimetric Studies of the High-7c Superconductor YBa2Cu3Ox

1987 ◽  
Vol 99 ◽  
Author(s):  
Y. H. Han ◽  
D. W. Monroe
Keyword(s):  
Electrical Conductivity ◽  
Electrical Resistivity ◽  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Oxygen Stoichiometry ◽  
Linear Temperature Dependence ◽  
Linear Temperature ◽  
Electrical Conductivities ◽  
Electrical Resistivities ◽  
Electron Holes

ABSTRACTNonstoichiometry in YBa2Cu3Ox has been studied by means of equilibrium electrical conductivity and thermogravimetric method. We have observed a strong correlation between electrical resistivity and oxygen stoichiometry (x) at high temperature. Electrical resistivities increase linearly from the superconducting onset tcmperature(100 K) to 450 C where oxygen starts to evolve from this material, and then begin to deviate from linear temperature dependence. The experimental results indicate that electrical resistivity in this material is associated with the defect species (charge carrier) population due to oxygen stoichiometry. Electrical conductivities were also measured as a function of oxygen partial pressure (1 to 10−4 atm) at various temperatures. At P(OI) > 101 atm the conductivity shows a l/4th slope dependence on oxygen partial pressure while at P(0;) < 10 f atm the conductivity is proportional to P(O2)1/2- The conductivity behavior with oxygen stoichiometry suggests that the electron holes associated with Cu+ play an important role as charge carriers in this material, and even at x < 6.5 p-typc conduction is predominant.

Electrical and thermal resistivity of the transition elements at low temperatures

1959 ◽  
Vol 251 (995) ◽  
pp. 273-302 ◽  
Keyword(s):  
Electrical Resistivity ◽  
Transport Equation ◽  
Low Temperatures ◽  
Group Iv ◽  
Standard Theory ◽  
Thermal Resistivity ◽  
Transition Elements ◽  
Thermal Vibrations ◽  
The Ideal

The results of measurements on 20 transition elements are reported giving values for the thermal resistivity, W , from 2 to about 140 °K and for electrical resistivity, p , from 2 to about 300 °K. Values of the ‘ideal’ resistivities, W i and p i { (due to scattering of the electrons by thermal vibrations), are deduced from these and tabulated for various temperatures. Comparisons are made with values for Cu, Ag, Au and Na and with the predictions of the ‘standard’ theory, i.e. solutions of the transport equation developed by Bloch, Grüneisen, Wilson, etc. Excepting Mn, p i follows a Bloch—Grüneisen function tolerably down to op5, although slight anomalies are shown by V, Cr, Fe, Co and Ni; at low temperatures behaviour is varied but below 10 °K in Mn, Fe, Co, Ni, Pd, Pt and perhaps in W and Nb, p i appears to vary nearly as T<super>2</super>. The parameter, piM 6 & (at 273 °K) has rather similar values for different members of each group, e.g. for Ti, Zr and Hf of group IV A. The ideal thermal resistivity, Wif can generally be approximated by the relation, WiIW ao = 2(Tld)2J 5(dlT), although for many elements, W i falls more rapidly than T 2 below010. Measurements on the relatively poor conductors, e.g. Ti, Zr and Hf, suggest the presence of an appreciable lattice conductivity, which affects the confidence with which values can be deduced for W i in these elements.

Electrical resistivity of gallium single crystals at low temperatures

1951 ◽  
Vol 209 (1099) ◽  
pp. 542-550 ◽  
Keyword(s):  
Electrical Resistivity ◽  
Specific Heat ◽  
Single Crystals ◽  
Low Temperatures ◽  
Room Temperature ◽  
Resistivity Measurements ◽  
Characteristic Temperatures ◽  
The Ideal

Electrical resistivity measurements on single crystals of gallium grown to conform approximately to the three axial directions have been extended to low temperatures, detailed investigation being made over the range 20.4 to 4.2° K. The anisotropy of this property increases in this region where the resistivity ratios for the three specimens are approximately 1: 2.1: 8 compared with 1: 2.1 6 : 6.5 5 at room temperature. The ‘ideal’ resistivity is proportional to T n , where n ≃ 4.45 for the range 5 to 12° K and decreases to about 3.9 for the range 12 to 20.4° K. The characteristic temperatures as derived from Grüneisen’s expression show relatively small differences for the three axial directions but decrease with decrease in temperature. Comparable variations with temperature are observed in the characteristic temperatures derived previously from specific heat measurements on gallium.

ELECTRICAL RESISTIVITY, HALL COEFFICIENT, AND THERMOELECTRIC POWER OF AuSb2 AND Cu2Sb

1964 ◽  
Vol 42 (3) ◽  
pp. 519-525 ◽  
Author(s):  
W. B. Pearson
Keyword(s):  
Electrical Conductivity ◽  
Electrical Resistivity ◽  
Thermoelectric Power ◽  
Hall Coefficient ◽  
Low Temperatures ◽  
Room Temperature ◽  
Iron Impurity

The electrical conductivity and absolute thermoelectric power of AuSb2 and Cu2Sb have been measured between 2.5° and 300 °K. Room-temperature Hall coefficients were also determined. Iron impurity causes a giant diffusion thermoelectric power at low temperatures in the compound Cu2Sb, as it has previously been found to do in Cu, Ag, and Au.

Temperature and Pressure Dependence of the Electrical Conductivity of Two Tetraalkylammonium Tetraalkylborate Salts

1999 ◽  
Vol 52 (5) ◽  
pp. 373 ◽  
Author(s):  
Nashiour Rohman ◽  
Sekh Mahiuddin ◽  
Raymond Aich ◽  
Klaus Tödheide
Keyword(s):  
Electrical Conductivity ◽  
Glass Transition ◽  
Transition Temperature ◽  
Pressure Dependence ◽  
Empirical Equation ◽  
Electrical Conductivities ◽  
Temperature And Pressure ◽  
Isothermal Equation ◽  
Key Parameter ◽  
The Ideal

Electrical conductivities of molten trimethylpentylammonium triethyloctylborate (N1115B2228) and triethylpentylammonium triethylpentylborate (N2225B2225) were measured as functions of temperature (c. 293 · 15–383 · 15 K) and pressure (from 1 bar to 5 kbar). Analysis of the temperature dependence of the electrical conductivity was made by using the Vogel–Tammann–Fulcher equation, κ = Aexp[ – B/(T – T0)]. The empirical nature of the pressure dependence of the B and T0 parameters has revealed the possibility of obtaining an isothermal equation to explain the pressure dependence of the electrical conductivity. Accordingly, an empirical equation of the form κ = a′exp(b′ P+c′ P2) has been found to describe the pressure dependence of the electrical conductivity. The ideal glass transition temperature, T0, is the key parameter in controlling the pressure dependence of the electrical conductivity for both systems under study.

Preparation and Electrical-Conductive Property of SnO2-Based Ceramics

2010 ◽  
Vol 105-106 ◽  
pp. 367-370 ◽  
Author(s):  
Guo Qiang Luo ◽  
Qiang Shen ◽  
Q.Z. Li ◽  
J. Li ◽  
Dong Ming Zhang ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Electrical Resistivity ◽  
Liquid Phase ◽  
Sintering Temperature ◽  
Processing Conditions ◽  
Sintering Aid ◽  
Densification Temperature ◽  
Wide Range ◽  
Electrical Resistivities ◽  
Conductive Property

In this study, SnO2-based ceramics, with CuO as sintering aid and Sb2O3 as activator of the electrical conductivity, was obtained by pressure-less sintering at 1100°C ~ 1470°C. Addition of antimony leads to a higher densification temperature. Densification behavior and microstructure development are strongly dependant on CuO and Sb2O3. CuO gives rise to a liquid phase; Sb2O3 retards the formation of liquid phase and hinders the growth of grain. The electrical resistivities of SnO2-based ceramics vary in a wide range from 10-2 to 107 Ω•cm, depending on starting compositions and processing conditions. The electrical resistivities of samples with different amounts of CuO and Sb2O3 show different trends with the increasing of sintering temperature. The addition of antimony rapidly promotes electrical conductivity of SnO2-based ceramics containing CuO as the solid solution reaction of Sb2O3-SnO2. As the additions of CuO and Sb2O3 are the same, the electrical resistivity arrives the minimal value of 4.72×10-2 Ω•cm for 99%SnO2+0.5%CuO +0.5%Sb2O3 at 1470°C. More content of Sb2O3 than CuO causes the degression of density and the rising of electrical resistivity of ceramics.

Temperature Dependence of the Electrical Conductivity of Poly(Benzo[1,2-b:4,5-b'] Dithiophene-4,8-Diyl Vinylene) and Poly(Dodecylthiophene)

1997 ◽  
Vol 488 ◽  
Author(s):  
R. C Hyer ◽  
R. G. Pethe ◽  
T. Yogi ◽  
S. C. Sharma ◽  
J. Wang ◽  
...  
Keyword(s):  
Thin Films ◽  
Electrical Conductivity ◽  
Temperature Dependence ◽  
Low Temperatures ◽  
Room Temperature ◽  
Thermal Fluctuation ◽  
Variable Range Hopping ◽  
Tunneling Model ◽  
Three Samples ◽  
Electrical Conductivities

AbstractWe present results for the electrical conductivity (σ) of thin films of poly(benzo[1,2-b:4,5- b']dithiophene-4,8-diyl vinylene) (PBDV) and poly (dodecylthiophene) (PDDT) as a function of temperature in the range 15-295K. The polymers were doped with FeC13 and PF6 which resulted in electrical conductivities differing by two orders of magnitude at room temperature. We examine three sets of σ(T)-data by using the variable-range hopping (VRH) model that predicts a linear relationship between ln(T1/2σ) and T1/4. We observe a change in the slope of the ln(T1/2σ) vs T14 relationship in all three samples at low temperatures. We also analyze the temperature dependence of the resistivity of PBDV by using the thermal fluctuation-induced tunneling model.

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