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Journal ArticleDOI

Hall effect in thin films of gold-silver alloys

01 Sep 1976-International Journal of Electronics (Taylor & Francis Group)-Vol. 41, Iss: 3, pp 285-292
TL;DR: In this article, an effective relaxation time is deduced from the variation of the Hall coefficient with the concentration which is found to be proportional to the mean free path of the electrons.
Abstract: Measurements on Hall constant and magnetoresistance of thin films (350 A-800 A) of Ag-Au alloys with concentrations up to 20% gold have been made. An effective relaxation time is deduced from the variation of the Hall coefficient with the concentration which is found to be proportional to the mean free path of the electrons. The mean free path of the film decreases by about a factor of 3 from the bulk value for silver on the addition of gold to silver. The results are consistent with those of other workers who have used different methods and also indicate that the relaxation time is anisotropic in thin films of alloy. Size effects have also been discussed.
Citations
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Journal ArticleDOI
TL;DR: It was found that topologically disordered 3D nanoporosity leads to extremely low magnetoresistance and anomalous temperature dependence as the characteristic length of nanoporous gold is tuned to be approximately 14 nm.
Abstract: We report the electric conductivity of three-dimensional (3D) nanoporous gold at low temperatures and in strong magnetic fields. It was found that topologically disordered 3D nanoporosity leads to extremely low magnetoresistance and anomalous temperature dependence as the characteristic length of nanoporous gold is tuned to be approximately 14 nm. This study underscores the importance of 3D topology of a nanostructure on electronic transport properties and has implications in manipulating electron transport by tailoring 3D nanostructures.

77 citations

Journal ArticleDOI
TL;DR: In this paper, the Boltzmann transport equation was used to define an effective relaxation time for thin metallic films subjected to a transverse magnetic field, and analytical expressions were derived for the Hall coefficient and conductivity in the case of nearly specular scattering on external surfaces.
Abstract: Defining an effective relaxation time and then using the Boltzmann transport equation, analytical expressions have been derived, in the case of nearly specular scattering on external surfaces (p>or=0.5), for the Hall coefficient and conductivity in thin metallic films subjected to a transverse magnetic field. The results for moderately high magnetic field agree well with previous theoretical works; at low magnetic field the Hall coefficient in thin films is greater than the bulk value RH0 and becomes identical with RH0 in strong magnetic field. The theoretical predictions agree well with experimental data on copper and potassium thin films.

21 citations

Journal ArticleDOI
TL;DR: In this article, a three-dimensional grain boundary model is used to calculate the transport properties of fine-grained films where background and grain boundaries scattering processes occur simultaneously, and analytical expressions are easily derived for the Hall coefficient and conductivity in polycrystalline films subjected to a transverse magnetic field.

13 citations

Journal ArticleDOI
TL;DR: In this paper, the authors derived analytical equations for the conductivity and the Hall coefficient of thin metallic films subjected to a longitudinal electric field and a transverse magnetic field from previously proposed general expressions.

13 citations

Journal ArticleDOI
TL;DR: The transverse Hall coefficient of thin monocrystalline films was derived from the recently presented bidimensional conduction model by introducing a term in the Boltzmann equation representing the effective mean free path as discussed by the authors.
Abstract: The transverse Hall coefficient of thin monocrystalline filmsRHF is derived from the recently presented bidimensional conduction model by introducing a term in the Boltzmann equation representing the effective mean free path. Numerical evaluations ofRHF show that the size effect inRHF is less marked than that in resistivity and is much more sensitive to grain-boundary scattering than it is to external-surface scattering. Good agreement with the results from the previous experiments of several authors is found.

12 citations

References
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Journal ArticleDOI
P. E. King-smith1
TL;DR: In this article, the de Haas-van Alphen effect in dilute silver and gold-based alloys, using the pulsed-field technique, is used to study the effect of alloying on both the electronic relaxation time and the cross-sectional area of specific orbits of the Fermi surface.
Abstract: Observations of the de Haas-van Alphen effect in dilute silver and gold-based alloys, using the pulsed-field technique, are used to study the effect of alloying on both the electronic relaxation time and the cross-sectional area of specific orbits of the Fermi surface. The results confirm Shoenberg's suggestion that the scattering of neck electrons for the AuAg system is less than the average for the Fermi surface and suggest that this is also true for the AuPt system. For some specimens, the scattering of neck electrons was found to be greater than the scattering derived from resistivity measurements; it is suggested that this may be due to scattering from lattice distortions such as dislocations. Comparison of the relaxation times for the 〈111〉 belly orbit with those derived from resistivity, indicates that for most specimens the results were consistent with isotropic scattering, but for some pure specimens there was a preponderance of small angle scattering, while for the AgCu system backward ...

25 citations

Journal ArticleDOI
TL;DR: In this article, a method for determining electron relaxation time anisotropies in metals is suggested and presented along with preliminary data taken at 4.2 Ω(n) K using a single crystal grown from 99.999% pure copper, in terms of the Pippard model of the Fermi surface of copper.
Abstract: A method for determining electron relaxation time anisotropies in metals is suggested and presented along with preliminary data taken at 4.2\ifmmode^\circ\else\textdegree\fi{}K using a single crystal grown from 99.999% pure copper. The analysis is based on the behavior of the attenuation of ultrasonic waves by conduction electrons in the high magnetic field limit. The data are discussed in terms of the Pippard model of the Fermi surface of copper. The technique also allows a rather direct test of the free electron theory of ultrasonic attenuation in that shear wave wave measurements are used in determining the total attenuation caused by the conduction electrons. It is suggested that a study of high-field shear wave attenuation will allow the total electronic attenuation to be found in any metal, whereas previously it has been possible to determine this quantity only for superconductors. On the rough experimental model used it is found that the relaxation time of electrons in neck orbits is several times larger than that of the other orbits studied. The relaxation times are of the order of ${10}^{\ensuremath{-}10}$ sec, and are impurity limited at 4.2\ifmmode^\circ\else\textdegree\fi{}K. Mean free paths are found to be about 20 times smaller than estimated from the number of magnetoacoustic oscillations.

23 citations

Journal ArticleDOI
TL;DR: In this paper, it is suggested that in the Ag-Au system the effects upon the Hall coefficient of the impurity scattering and the band structure can be separated, and further information is then obtained about the temperature dependence of these effects.
Abstract: It is suggested that in the Ag-Au system the effects upon the Hall coefficient of the impurity scattering and the band structure can be separated. Further information is then obtained about the temperature dependence of these effects.

19 citations

Journal ArticleDOI

12 citations

Journal ArticleDOI
TL;DR: In this article, the effective number of conduction electrons calculated using a one-band model is compared with that obtained for the copper-nickel alloy system and a similarity in behavior is found.

11 citations