Specific heat of InBi below 30 K

1981 ◽  
Vol 59 (4) ◽  
pp. 567-575 ◽  
Author(s):  
Douglas L. Martin
Keyword(s):  
Specific Heat ◽  
Debye Temperature ◽  
Thermal Contact ◽  
Adiabatic Calorimeter ◽  
Electronic Specific Heat ◽  
Good Thermal Contact ◽  
Debye Temperatures ◽  
Isoperibol Calorimeter ◽  
Specific Heat Coefficient

There was difficulty in establishing good thermal contact with InBi, a very anisotropic material. This is not believed to have affected results from the 2.5–30 K adiabatic calorimeter. However, results from the 0.35–3 K isoperibol calorimeter are a few percent high in the overlap range owing to uncompensated heat loss during heating periods. Consequently there is some uncertainty in the determination of the electronic specific heat but little uncertainty in Debye temperatures above 1 K (because the lattice specific heat is so large). Despite the great anisotropy, mass-layering, and easy cleaving in one direction, the variation of Debye temperature with temperature is quite normal, there being no evidence of two-dimensional behavior (cf. graphite). The preferred analysis gives the electronic specific heat coefficient as 97.1 ± 0.8 μcal K−2 g-at.−1 (406 ± 3 μJ K−2 g-at.−1) and the low temperature limiting value of Debye temperature as 139.8 ± 0.4 K.

Low temperature specific heats of zinc alloyed with silver

1975 ◽  
Vol 343 (1634) ◽  
pp. 363-374 ◽  
Keyword(s):  
Low Temperature ◽  
Fermi Level ◽  
Specific Heat ◽  
Debye Temperature ◽  
Density Of States ◽  
Electronic Specific Heat ◽  
Pure Zinc ◽  
Specific Heats ◽  
Complete Breakdown ◽  
Specific Heat Coefficient

Measurements of the electronic specific heat coefficient and of the limiting Debye temperature are reported for pure zinc and for two n-phase alloys containing 2 at. % and 4 at. % silver in zinc, respectively. After a correction for electron-phonon enhancement the electronic specific heat coefficient for pure zinc differs by only a small percentage from the calculated value reported in the literature on the basis of a band calculation. The results for the alloys show a decreasing trend of the density of states at the Fermi level when silver is added to zinc. This is contrary to a prediction based on a rigid band approach. Hence, the results indicate a complete breakdown of the rigid band condition on alloying. The reasons for this are most likely associated with the influence of the d band electrons or with charge distribution effects between solute and solvent atoms.

SPECIFIC HEATS OF MANGANESE AND BISMUTH AT LIQUID HYDROGEN TEMPERATURES

1949 ◽  
Vol 27a (2) ◽  
pp. 9-16 ◽  
Author(s):  
L. D. Armstrong ◽  
H. Grayson-Smith
Keyword(s):  
Specific Heat ◽  
Accurate Determination ◽  
Theoretical Formula ◽  
Electronic Specific Heat ◽  
Debye Function ◽  
Specific Heats ◽  
Simple Cubic ◽  
Limited Temperature ◽  
Specific Heat Coefficient

New measurements of the specific heats of manganese and bismuth in the temperature range 14° to 22° K. are reported. The specific heats of these metals are compared with theory. In both cases the approximate theoretical formula[Formula: see text]where CD(x) is the Debye function, is accurately obeyed over the limited temperature region concerned. However, comparison with measurements at other temperatures shows that this may lead to erroneous conclusions. For manganese a precise conclusion is not possible, and it is estimated that the electronic specific heat coefficient A lies between 0.0035 and 0.0040, while θ varies with temperature from 365 to 390 degrees. For bismuth it is concluded that the electronic specific heat is negligible. This permits an accurate determination of θ, and it is found that the variation of θ with temperature is remarkably similar to that predicted by Blackman for a simple cubic lattice.

Specific heat below 3 °K of a gold–zinc and a gold–indium alloy

1969 ◽  
Vol 47 (10) ◽  
pp. 1077-1081 ◽  
Author(s):  
Douglas L. Martin
Keyword(s):  
Specific Heat ◽  
Face Centered Cubic ◽  
Electronic Specific Heat ◽  
Confidence Limits ◽  
Electric Field Gradients ◽  
Field Gradients ◽  
Atomic Silver ◽  
Face Centered ◽  
Specific Heat Coefficient ◽  
Limiting Value

Face-centered-cubic alloys of gold with 10 atomic % zinc (divalent) and 10 atomic % indium (trivalent), respectively, were measured in the range 0.4 to 3.0 °K. The coefficients of the nuclear specific-heat term were 1.80 ± 0.07 μcal °K/g atom for AuZn and 1.29 ± 0.06 μcal °K/g atom for AuIn (95% confidence limits). For a gold–10 atomic % silver (monovalent) alloy (Martin 1968) the nuclear term was 0.44 μcal °K/g atom. These results show that electric field gradients in alloys are not simply proportional to the valence difference of the components, a conclusion which may be drawn from NMR results. For the AuZn alloy the electronic specific-heat coefficient (γ) is 153.4 ± 0.7 μcal/°K2 g atom and the limiting value of the Debye temperature (θ0c) is 177.0 ± 0.5 °K. For the AuIn alloy γ is 185.9 ± 0.7 μcal/°K2 g atom and θ0c is 159.1 ± 0.3 °K.

Thermal Properties of Thin Metallic Layer Deposited on Insulators: Effect of the Interface on the Independent Determination of the Thermal Diffusivity and Conductivity of the Layer

2008 ◽  
Author(s):  
Danie`le Fournier ◽  
Jean Paul Roger ◽  
Christian Fretigny
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Thermal Diffusivity ◽  
Thermal Resistance ◽  
Thermal Contact ◽  
Heat Diffusion ◽  
Metallic Layer ◽  
Good Thermal Contact ◽  
Lateral Heat

Lateral heat diffusion thermoreflectance is a very powerful tool for determining directly the thermal diffusivity of layered structures. To do that, experimental data are fitted with the help of a heat diffusion model in which the ratio between the thermal conductivity k and the thermal diffusivity D of each layer is fixed, and the thermal properties of the substrate are known. We have shown in a previous work that it is possible to determine independently the thermal diffusivity and the thermal conductivity of a metallic layer deposited on an insulator, by taking into consideration all the data obtained at different modulation frequencies. Moreover, it is well known that to prevent a lack of adhesion of a gold film deposited on substrates like silica, an intermediate very thin (Cr or Ti) layer is deposited to assure a good thermal contact. We extend our previous work: the asymptotic behaviour determination of the surface temperature wave at large distances from the modulated point heat source for one layer deposited on the substrate to the two layers model. In this case (very thin adhesion coating whose thermal properties and thickness are known), it can be establish that the thermal diffusivity and the thermal conductivity of the top layer can still be determined independently. It is interesting to underline that the calculus can also be extended to the case of a thermal contact resistance which has often to be taken into account between two solids. We call thermal resistance a very thin layer exhibiting a very low thermal conductivity. In this case, the three parameters we have to determine are the thermal conductivity and the thermal diffusivity of the layer and the thermal resistance. We will show that, in this case, the thermal conductivity of the layer is always obtained independently of a bound of the couple thermal resistance – thermal diffusivity, the thermal diffusivity being under bounded and the thermal resistance lower bounded. Experimental results on thin gold layers deposited on silica with and without adhesion layers are presented to illustrate the method. Discussions on the accuracy will also be presented.

Hole density dependence of the low temperature electronic specific heat coefficient of La2-xSrxCaCu2O6 with weakly localized electrons

1993 ◽  
Vol 209 (4) ◽  
pp. 553-558 ◽  
Author(s):  
Takashi Nishikawa ◽  
Shin-ichi Shamoto ◽  
Masafumi Sera ◽  
Masatoshi Sato ◽  
Shigeki Ohsugi ◽  
...  
Keyword(s):  
Low Temperature ◽  
Specific Heat ◽  
Density Dependence ◽  
Hole Density ◽  
Electronic Specific Heat ◽  
Specific Heat Coefficient ◽  
Localized Electrons

Spin Disorder Resistivity and Electronic Specific Heat of Gd4(Co1-xCux)3 Compounds

2008 ◽  
Vol 587-588 ◽  
pp. 333-337
Author(s):  
T.M. Seixas ◽  
M.A. Salgueiro da Silva ◽  
O.F. de Lima ◽  
J. Lopez ◽  
Hans F. Braun ◽  
...  
Keyword(s):  
Specific Heat ◽  
Linear Dependence ◽  
Magnetic Moments ◽  
Spin Fluctuations ◽  
Electronic Specific Heat ◽  
Spin Disorder ◽  
Structure Changes ◽  
Thermal Disorder ◽  
Specific Heat Coefficient ◽  
Electron Band Structure

In this work, we present a study of the spin disorder resistivity ( ρm∞) and the electronic specific heat coefficient ( γ) in Gd4(Co1-xCux)3 compounds, with x = 0, 0.05, 0.10, 0.20, 0.30. The experimental results show a strongly non-linear dependence of ρm∞ on the de Gennes factor which, in similar intermetallic compounds, is usually attributed to the existence of spin fluctuations on the Co 3d bands and its amplification by the thermal disorder of the Gd magnetic moments through the Gd-Co exchange coupling. Using a novel combined analysis of ρm∞ and γ, we show, however, that only electron band structure changes are involved in the anomalous behaviour of ρm∞ and that a linear dependence of ρm∞ on the de Gennes factor is obtained when the variation of the effective mass is properly taken into account.

Specific heat below 3 °K, melting point, and melting heat of rubidium and cesium

1970 ◽  
Vol 48 (11) ◽  
pp. 1327-1339 ◽  
Author(s):  
Douglas L. Martin
Keyword(s):  
Thermal Analysis ◽  
Melting Point ◽  
Low Temperature ◽  
Specific Heat ◽  
Alkali Metals ◽  
Effective Masses ◽  
Debye Temperatures ◽  
Latent Heat Of Melting ◽  
Specific Heat Coefficient ◽  
Limiting Value

Specific heat measurements were made between 0.4 and 3.0 °K. For rubidium (nominal purity 99.9%, actual purity probably ~ 99.99%) the electronic specific heat coefficient γ is 624.6 ± 6.5 μcal/°K2 g atom and the low temperature limiting value of the Debye temperature (ΘOoc) is 56.5 ± 0.2 °K. For cesium (nominal purity 99.99%, actual purity probably ~ 99.97%) γ is 950 ± 20 μcal/°K2 g atom and ΘOoc is 40.5 ± 0.3 °K. These Debye temperatures are in fair agreement with ΘOoc1 values calculated from low temperature elastic constant measurements. Electron effective masses (calculated from γ) are 1.37 ± 0.01 for Rb and 1.80 ± 0.04 for Cs. Thermal effective masses for all the alkali metals are compared with recent theoretical results. Sample purities were checked by an independent spectrographic analysis and by making a thermal analysis in the melting region on the actual specific heat samples. These thermal analysis results led to a review of earlier work on the melting of these metals and the following revised values of melting point and latent heat of melting were obtained: Rb: 312.47 ± 0.02 °K, 524.3 ± 1.0 cal/g atom; Cs: 301.67 ± 0.13 °K, 501.0 ± 1.0 cal/g atom.

Electronic specific heat coefficient and magnetic entropy of icosahedral Mg-RE-Zn (RE=Gd, Tb and Y) quasicrystals

1995 ◽  
Vol 7 (22) ◽  
pp. 4183-4191 ◽  
Author(s):  
Y Hattori ◽  
K Fukamichi ◽  
K Suzuki ◽  
A Niikura ◽  
A P Tsai ◽  
...  
Keyword(s):  
Specific Heat ◽  
Electronic Specific Heat ◽  
Magnetic Entropy ◽  
Specific Heat Coefficient

Enhancement of the electronic specific heat coefficient in (Co1−xNix)2ScSn

1993 ◽  
Vol 73 (10) ◽  
pp. 5427-5429 ◽  
Author(s):  
C. J. Fuller ◽  
Z. W. Chen ◽  
N. Anbalagan ◽  
C. L. Lin ◽  
T. Mihalisin
Keyword(s):  
Specific Heat ◽  
Electronic Specific Heat ◽  
Specific Heat Coefficient
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