scholarly journals Temperature Dependence of the Hall Coefficient of Thin Films

1979 ◽  
Vol 6 (1) ◽  
pp. 19-22
Author(s):  
C. R. Tellier ◽  
C. Pichard ◽  
A. J. Tosser
Keyword(s):  
Thin Films ◽  
Temperature Dependence ◽  
Temperature Coefficient ◽  
Free Path ◽  
Hall Coefficient ◽  
Mean Free Path ◽  
Theoretical Expression ◽  
Metallic Films ◽  
Conduction Model ◽  
The Mean

A theoretical expression for the temperature coefficientβRHof the Hall coefficientRHFof metallic films is deduced from the Fuchs–Sondheimer conduction model. The general expression takes into account the deviation introduced by the geometrical limitation of the mean free path. This is negligible for relatively thick films (k≥ 1 forp= 0) and agrees with experiments previously reported by other authors.

The electrical properties of graphite

1953 ◽  
Vol 217 (1128) ◽  
pp. 9-26 ◽  
Keyword(s):  
Single Crystal ◽  
Free Path ◽  
Hall Coefficient ◽  
Mean Free Path ◽  
Free Electrons ◽  
Satisfactory Explanation ◽  
Wide Range ◽  
The Mean ◽  
Positive Holes ◽  
Crystalline Graphite

The Hall coefficient and resistivity of a range of polycrystalline graphites with different crystal sizes and a single crystal of Travancore graphite have been measured over a wide range of temperature. The number of free electrons has been found to be approximately 6x10 18 per cm 3 at room temperature; the variation with temperature cannot be accurately determined. The deficit of electrons in poorly crystalline graphite gives rise to positive Hall coefficients. Quenching removes electrons, and a study of this process has enabled the ratio of the mobilities of positive holes and electrons to be estimated at 0·80. An interesting effect has been observed in the variation of the Hall coefficient of the single crystal with field; no satisfactory explanation has been found for this phenomenon. The resistivity of polycrystalline graphite depends on the density and on the orientation and size of the crystals. From the variation of resistivity with temperature and the size of the crystals, the mean free path due to thermal scattering, has been found to be 2350 Å at 273° K; the variation of mean free path with temperature has been deduced. The product of effective mass and velocity of the free electrons has been determined as a function of temperature; the accuracy is limited by uncertainties in the number of free electrons.

Hall coefficient of thin films in a mean free path model

1978 ◽  
Vol 8 (11) ◽  
pp. 2357-2365 ◽  
Author(s):  
C R Tellier ◽  
M Rabel ◽  
A J Tosser
Keyword(s):  
Thin Films ◽  
Free Path ◽  
Hall Coefficient ◽  
Mean Free Path ◽  
Path Model

Experimentelle und theoretische Untersuchungen des isothermen und des adiabatischen Hall-Effektes an Se

1953 ◽  
Vol 8 (8) ◽  
pp. 453-459
Author(s):  
Rolf Diestel
Keyword(s):  
Thermal Conductivity ◽  
Theoretical Result ◽  
Free Path ◽  
Hall Coefficient ◽  
Mean Free Path ◽  
Type Semiconductor ◽  
The Mean ◽  
The Difference ◽  
P Type

Supposing an arbitrary dependence of the mean free path on energy, the isothermal and the adiabatic Hall coefficients are calculated for a p-type semiconductor by means of the theory of electrons. The difference between the Hall coefficients calculated in this way decrease considerably with increasing thermal conductivity of the lattice. Even for substances with very small thermal conductivity (i. e. Se etc.), the difference amounts to only about 1% in relation to the isothermal Hall coefficient. This theoretical result is proved by measurements on Se; the measured difference slightly exceeds the limit of error (5,2±4,1)%.

scholarly journals Ballistic Heat Transport in Nanocomposite: The Role of the Shape and Interconnection of Nanoinclusions

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1982
Author(s):  
Paul Desmarchelier ◽  
Alice Carré ◽  
Konstantinos Termentzidis ◽  
Anne Tanguy
Keyword(s):  
Thermal Conductivity ◽  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Free Path ◽  
Mean Free Path ◽  
Strong Increase ◽  
Moderate Increase ◽  
Energy Propagation ◽  
The Mean ◽  
Dynamics Simulations

In this article, the effect on the vibrational and thermal properties of gradually interconnected nanoinclusions embedded in an amorphous silicon matrix is studied using molecular dynamics simulations. The nanoinclusion arrangement ranges from an aligned sphere array to an interconnected mesh of nanowires. Wave-packet simulations scanning different polarizations and frequencies reveal that the interconnection of the nanoinclusions at constant volume fraction induces a strong increase of the mean free path of high frequency phonons, but does not affect the energy diffusivity. The mean free path and energy diffusivity are then used to estimate the thermal conductivity, showing an enhancement of the effective thermal conductivity due to the existence of crystalline structural interconnections. This enhancement is dominated by the ballistic transport of phonons. Equilibrium molecular dynamics simulations confirm the tendency, although less markedly. This leads to the observation that coherent energy propagation with a moderate increase of the thermal conductivity is possible. These findings could be useful for energy harvesting applications, thermal management or for mechanical information processing.

Experiments on the flow of heat in liquid helium below 0.7 °K

1958 ◽  
Vol 246 (1246) ◽  
pp. 390-405 ◽  
Keyword(s):  
Thermal Conductivity ◽  
Liquid Helium ◽  
Free Path ◽  
Empirical Relation ◽  
Mean Free Path ◽  
Series Of Experiments ◽  
The Mean ◽  
Set Up ◽  
Low Pressures ◽  
Measured Thermal Conductivity

A series of experiments has been performed to study the steady flow of heat in liquid helium in tubes of diameter 0.05 to 1.0 cm at temperatures between 0.25 and 0.7 °K. The results are interpreted in terms of the flow of a gas of phonons, in which the mean free path λ varies with temperature, and may be either greater or less than the diameter of the tube d . When λ ≫ d the flow is limited by the scattering of the phonons at the walls, and the effect of the surface has been studied, but when λ ≪ d viscous flow is set up in which the measured thermal conductivity is increased above that for wall scattering. This behaviour is very similar to that observed in the flow of gases at low pressures, and by applying kinetic theory to the problem it can be shown that the mean free path of the phonons characterizing viscosity can be expressed by the empirical relation λ = 3.8 x 10 -3 T -4.3 cm. This result is inconsistent with the temperature dependence of λ as T -9 predicted theoretically by Landau & Khalatnikov (1949).

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