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.
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TL;DR: In this paper, the resistance of thin films of silver, copper, indium and aluminium were measured using annealed and unannealed films of chromium-copper alloy as electrodes.
Abstract: The resistance of thin films of silver, copper, indium and aluminium deposited onto clean glass substrates were measured using annealed and unannealed films of chromium-copper alloy as electrodes. The percentage variation in resistance for different metal films differ with annealed and unannealed electrodes. Formation of oxide and alloying at the electrodefilm junction are discussed taking into account the observed variations in resistance. Microscopic observations are also made of the film-electrode junctions.
01 Jan 1982
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TL;DR: In this paper, the optical constants for the noble metals (copper, silver, and gold) from reflection and transmission measurements on vacuum-evaporated thin films at room temperature, in the spectral range 0.5-6.5 eV.
Abstract: The optical constants $n$ and $k$ were obtained for the noble metals (copper, silver, and gold) from reflection and transmission measurements on vacuum-evaporated thin films at room temperature, in the spectral range 0.5-6.5 eV. The film-thickness range was 185-500 \AA{}. Three optical measurements were inverted to obtain the film thickness $d$ as well as $n$ and $k$. The estimated error in $d$ was \ifmmode\pm\else\textpm\fi{} 2 \AA{}, and that in $n$, $k$ was less than 0.02 over most of the spectral range. The results in the film-thickness range 250-500 \AA{} were independent of thickness, and were unchanged after vacuum annealing or aging in air. The free-electron optical effective masses and relaxation times derived from the results in the near infrared agree satisfactorily with previous values. The interband contribution to the imaginary part of the dielectric constant was obtained by subtracting the free-electron contribution. Some recent theoretical calculations are compared with the results for copper and gold. In addition, some other recent experiments are critically compared with our results.
17,509 citations
TL;DR: In this paper, experimental data for the optical constants of Ag and Cu extending to 25 eV are discussed in terms of three fundamental physical processes: (1) free-electron effects, (2) interband transitions, and (3) collective oscillations.
Abstract: Experimental data for the optical constants of Ag and Cu extending to 25 eV are discussed in terms of three fundamental physical processes: (1) free-electron effects, (2) interband transitions, and (3) collective oscillations. Dispersion theory is used to obtain an accurate estimate of the average optical mass characterizing the free-electron behavior over the entire energy range below the onset of interband transitions. The values are ${m}_{a}=1.03\ifmmode\pm\else\textpm\fi{}0.06$ for Ag and 1.42\ifmmode\pm\else\textpm\fi{}0.05 for Cu. The interband transitions to 11 eV are identified tentatively using Segall's band calculations. Plasma resonances involving both the conduction band and $d$ electrons are identified and described physically.
931 citations
TL;DR: In this article, the shape of the Fermi surface is made to depend on a single parameter which can be interpreted as the pseudo-potential of the {111} atomic planes acting on an orthogonalized plane wave, giving rise to an energy gap of 5-10 ev at the zone boundaries.
Abstract: The Fermi Surfaces in Cu, Ag and Au are now known to be greatly distorted, with thick ‘necks’ passing through the zone boundaries. In this paper we enquire whether such an electronic structure is quantitatively consistent with the observed transport coefficients. The mathematical model is quite simple; the shape of the Fermi surface is made to depend on a single parameter which can be interpreted as the pseudo-potential of the {111} atomic planes acting on an orthogonalized plane wave, giving rise to an energy gap of 5–10 ev at the zone boundaries. Various integrals over the Fermi surface can then be evaluated by elementary methods, and compared with the corresponding experimental quantities. The electronic specific heat and optical mass in the pure metals are consistent with the model. The galvanomagnetic effects are shown to depend a great deal on the anisotropy of the electron relaxation time, whose variation with energy is also probably the electron relaxation time, whose variation with energ...
165 citations
TL;DR: In this paper, the optical constants of thin Ag films are determined from measurements of both their transmittance and reflectance, in terms of intra and interband transitions, in relation with the film crystallographic structure.
Abstract: The optical constants of thin Ag films are determined from measurements of both their transmittance and reflectance. The complex dielectric constant is discussed in terms of intra and interband transitions, in relation with the film crystallographic structure. The optical mass of the conduction electrons is found to be very low, 0·87; their optical relaxation time to depend strongly on the film structure and to be smaller than their electrical relaxation time. The absorption due to interband transitions is considered. A supplementary absorption band related to film imperfections is observed in some cases. Plasma oscillations are also studied in relation with the film quality.
75 citations