Hall Effect and Conductivity in Porous Media

Juretschke, H. J.; Landauer, Rolf; Swanson, James A.

doi:10.1063/1.1722496

Cited by 176 publications

(44 citation statements)

References 3 publications

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“…The effective conductivity of porous materials can be described by the Maxwell equation, 21) which is applicable to heterogeneous materials composed of spherical particles. Juretscheke et al 22) proposed a mathematical model to interpret the relationship between the porosity and conductivity of ceramic materials based on Maxwell equation. Assuming that spherical pores are homogeneously distributed in dense materials, the relationship between relative conductivity and porosity can be expressed as…”

Section: Resultsmentioning

confidence: 99%

Thermoelectric Properties of Solution Combustion Synthesized Al-Doped ZnO

et al. 2008

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Thermoelectric properties of Al-doped ZnO prepared by solution combustion synthesis using urea as fuel and sintered by spark plasma sintering were investigated for developing an energy-and time-saving synthesis method to decrease its thermal conductivity without a significant deterioration in other thermoelectric properties. The desired materials were successfully synthesized and sintered. The thermoelectric properties of the synthesized products subjected to planetary ball milling (PBM) treatment before sintering were compared with those of synthesized products not subjected to PBM treatment; the results showed that the former products had a larger power factor and higher thermal conductivity than the latter products. The thermal conductivity of all as-synthesized products was in the range of 8.3-19.7 WÁm À1 ÁK À1 at room temperature, which was significantly lower than that of the products synthesized by a conventional solid-state reaction method. (Zn 0:99 Al 0:01 )O obtained by PBM had the highest dimensionless figure of merit ZT of 0.050 at 863 K. From these results, it is inferred that solution combustion synthesis is an effective method for synthesizing Al-doped ZnO with relatively low thermal conductivity for high-temperature thermoelectric applications.

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Section: Resultsmentioning

confidence: 99%

Thermoelectric Properties of Solution Combustion Synthesized Al-Doped ZnO

et al. 2008

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“…While the exact results found by Landauer et al in Refs. [40,41] are valid for arbitrary field strength, other results have been found more recently which are asymptotically exact only in the strong field limit, i.e., when the Hallto-Ohmic resistivity ratio in at least one constituent is much greater than 1 [49]- [52]. In 1957, Landauer wrote a pioneering paper on electronic transport due to localized scatterers in a metal.…”

Section: Classical Inhomogeneous Systemsmentioning

confidence: 99%

Heterogeneity and disorder: Contributions of Rolf Landauer

Halperin¹,

Bergman²

2010

Physica B: Condensed Matter

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“…ratios ci = p1/p2 and P = 12/1, to obtain relationships between the measured carrier concentration-of the film, n,, and the carrier concentraparticles or grains making up the films may be at tion in the material n,, and the film and material least as important in determining the resulting mobilities, pH and p,, respectively. film properties (Juretschke et al 1956;Blount By making the intergranular material the same is the measure of the barrier resistance. It is found that [4] reduces to and so the measured value of the carrier concentration equals that in the conducting material.…”

Section: Granular Structure Of Filmsmentioning

confidence: 99%

Effect of Oxygen on the Temperature Dependence of Electrical Properties of Reactively Sputtered Tantalum Films

Waterhouse¹,

Westwood²

1971

Can. J. Phys.

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The negative temperature coefficient of resistivity (TCR) displayed by p-Ta, which has thus far not been satisfactorily explained, has been examined by measuring the variation of electrical resistivity with temperature, from -2S300 OK, and by measuring the Hall coefficients, at room temperature and a t 77 OK, of films containing up to -60 at.% oxygen. The Hall measurements indicate carrier concentrations of -loz2 ~m -~ and mobilities of -1 cm2/V s. The analysis of the results has considered the granular structure of the films and has subsequently compared these results with an 'activated tunneling' model of conduction. Theoretical calculations which assume the film to be comprised of cubic grains separated by T a 2 0 5 agree well with the experimental measurements.Metallic conduction still appears to be contributing to the film properties even at the highest oxygen concentrations of the present investigation.Le coefficient negatif de variation de resistivite en fonction de la temperature (TCR) du p-Ta, qui n'a pas encore ete expliquk de f a~o n satisfaisante, a etC examine en mesurant la resistivite Clectrique en fonction de la temperature de 20 a 300 "K et en mesurant, a temperature ambiante et a 77 OK, les coefficients de Hall de films contenant jusqu'a 60% d'oxygene atomique. Les mesures d'effet Hall indiquent des concentrations de porteurs de cm-3 et des mobilites de -1 cm2/V s. Lors de I'analyse des resultats on a tenu compte de la structure granulaire des films et on a subsequemment compare ces resultats avec un modele "d'effet tunnel active" de la conduction. Des calculs theoriques, faits en supposant que le film est compose de grains cubiques sCparCs par Ta205, concordent tres bien avec les mesures expirimentales.La conduction metallique contribue aux proprietes du film mCme avec les plus fortes concentrations en oxygene utilisees au cours de cette investigation.

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Hall Effect and Conductivity in Porous Media

Cited by 176 publications

References 3 publications

Thermoelectric Properties of Solution Combustion Synthesized Al-Doped ZnO

Thermoelectric Properties of Solution Combustion Synthesized Al-Doped ZnO

Heterogeneity and disorder: Contributions of Rolf Landauer

Effect of Oxygen on the Temperature Dependence of Electrical Properties of Reactively Sputtered Tantalum Films

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