The electrical resistivity of lithium-6

The electrical resistivities of lithium -6 and lithium of natural isotopic composition have been studied between 4°K and room temperature. In addition, their absolute resistivities have been carefully compared at room temperature. These measurements show that the effect of ionic mass on electrical resistivity agrees with simple theoretical predictions, namely, that the properties of the conduction electrons in lithium do not depend on the mass of the ions, and that the characteristic lattice frequencies for the two pure isotopes are in the inverse ratio of the square roots of their ionic masses. A comparison with the specific heat results of Martin (1959, 1960), where the simple theory is found not to hold, indicates the possibility that anharmonic effects are present which affect the specific heat but not the electrical resistivity.

1963 ◽  
Vol 41 (12) ◽  
pp. 2252-2266 ◽  
Author(s):  
J.-P. Jan ◽  
W. B. Pearson ◽  
A. Kjekshus ◽  
S. B. Woods

The Au1−xSn phase has a homogeneity range within the limits 50.0 and 50.5 at.% Sn. The lattice constants and observed densities vary between the limits:[Formula: see text]The thermal conductivity, electrical resistivity, and absolute thermoelectric power of oriented single crystals of Au1−xSn have been measured between 2.5° K and room temperature. The results exhibit pronounced anisotropies. Measurements of the magnetic susceptibility between liquid air temperature and 650–750° K are also reported for three different Au1−xSn alloys.The various results are discussed, and some speculations are presented regarding the number of conduction electrons in AuSn.


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.


1997 ◽  
Vol 11 (09n10) ◽  
pp. 407-414 ◽  
Author(s):  
L.-S. Hsu ◽  
Y. D. Yao ◽  
Y. Y. Chen

The electrical resistivity and specific heat of NiGa were measured between 5 and 296 K and between 1.07 and 300 K, respectively, at zero magnetic field. This compound is metallic as shown from the room-temperature resistivity value (37.4 μΩ cm). The residual resistivity ratio is 1.32, which indicates the defect scattering dominates at low temperatures. The density of states at the Fermi energy and the Debye temperature obtained from the low-temperature specific-heat measurement are 1.48 states/eV formula unit and 202 K, respectively. The former is much higher than the value for NiAl. This observation suggests that the Ni d-band in NiGa is not completely filled.


Author(s):  
A.C. Daykin ◽  
C.J. Kiely ◽  
R.C. Pond ◽  
J.L. Batstone

When CoSi2 is grown onto a Si(111) surface it can form in two distinct orientations. A-type CoSi2 has the same orientation as the Si substrate and B-type is rotated by 180° degrees about the [111] surface normal.One method of producing epitaxial CoSi2 is to deposit Co at room temperature and anneal to 650°C.If greater than 10Å of Co is deposited then both A and B-type CoSi2 form via a number of intermediate silicides .The literature suggests that the co-existence of A and B-type CoSi2 is in some way linked to these intermediate silicides analogous to the NiSi2/Si(111) system. The phase which forms prior to complete CoSi2 formation is CoSi. This paper is a crystallographic analysis of the CoSi2/Si(l11) bicrystal using a theoretical method developed by Pond. Transmission electron microscopy (TEM) has been used to verify the theoretical predictions and to characterise the defect structure at the interface.


2019 ◽  
Author(s):  
Kazunori Miyamoto ◽  
Shodai Narita ◽  
Yui Masumoto ◽  
Takahiro Hashishin ◽  
Mutsumi Kimura ◽  
...  

Diatomic carbon (C<sub>2</sub>) is historically an elusive chemical species. It has long been believed that the generation of C<sub>2 </sub>requires extremely high “physical” energy, such as an electric carbon arc or multiple photon excitation, and so it has been the general consensus that the inherent nature of C<sub>2 </sub><i>in the ground state </i>is experimentally inaccessible. Here, we present the first “chemical” synthesis of C<sub>2 </sub>in a flask at <i>room temperature or below</i>, providing the first experimental evidence to support theoretical predictions that (1) C<sub>2 </sub>has a singlet biradical character with a quadruple bond, thus settling a long-standing controversy between experimental and theoretical chemists, and that (2) C<sub>2 </sub>serves as a molecular element in the formation of sp<sup>2</sup>-carbon allotropes such as graphite, carbon nanotubes and C<sub>60</sub>.


Author(s):  
Chandrakant Sarode ◽  
Sachin Yeole ◽  
Ganesh Chaudhari ◽  
Govinda Waghulde ◽  
Gaurav Gupta

Aims: To develop an efficient protocol, which involves an elegant exploration of the catalytic potential of both the room temperature and surfactant ionic liquids towards the synthesis of biologically important derivatives of 2-aminothiazole. Objective: Specific heat capacity data as a function of temperature for the synthesized 2- aminothiazole derivatives has been advanced by exploring their thermal profiles. Method: The thermal gravimetry analysis and differential scanning calorimetry techniques are used systematically. Results: The present strategy could prove to be a useful general strategy for researchers working in the field of surfactants and surfactant based ionic liquids towards their exploration in organic synthesis. In addition to that, effect of electronic parameters on the melting temperature of the corresponding 2-aminothiazole has been demonstrated with the help of thermal analysis. Specific heat capacity data as a function of temperature for the synthesized 2-aminothiazole derivatives has also been reported. Conclusion: Melting behavior of the synthesized 2-aminothiazole derivatives is to be described on the basis of electronic effects with the help of thermal analysis. Additionally, the specific heat capacity data can be helpful to the chemists, those are engaged in chemical modelling as well as docking studies. Furthermore, the data also helps to determine valuable thermodynamic parameters such as entropy and enthalpy.


2003 ◽  
Vol 793 ◽  
Author(s):  
Y. Amagai ◽  
A. Yamamoto ◽  
C. H. Lee ◽  
H. Takazawa ◽  
T. Noguchi ◽  
...  

ABSTRACTWe report transport properties of polycrystalline TMGa3(TM = Fe and Ru) compounds in the temperature range 313K<T<973K. These compounds exhibit semiconductorlike behavior with relatively high Seebeck coefficient, electrical resistivity, and Hall carrier concentrations at room temperature in the range of 1017- 1018cm−3. Seebeck coefficient measurements reveal that FeGa3isn-type material, while the Seebeck coefficient of RuGa3changes signs rapidly from large positive values to large negative values around 450K. The thermal conductivity of these compounds is estimated to be 3.5Wm−1K−1at room temperature and decreased to 2.5Wm−1K−1for FeGa3and 2.0Wm−1K−1for RuGa3at high temperature. The resulting thermoelectric figure of merit,ZT, at 945K for RuGa3reaches 0.18.


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