| 1. |
- Andersson, Odd E., et al.
(author)
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A study of temperature and pressure induced structural and electronic changes in SbCl5 intercalated graphite : Part IV: Basal plane resistivity
- 1995
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In: Journal of Materials Research. - 0884-2914 .- 2044-5326. ; 10:7, s. 1653-1660
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Journal article (peer-reviewed)abstract
- Using an inductive technique, we have measured the in-plane resistivity rhoa of stages 2, 4, 5, and 8 SbCl5-GIC's versus temperature T and pressure p in the ranges 130–300 K and 0–0.85 GPa. The room temperature values of rhoa range from 4.0 µOcm for the stages 5 sample to 7.7 µOcm for the stage 8 sample. At all pressures, rhoa shows a metallic temperature dependence rhoa ~ Ta, with 1 < a < 2, but in contrast to the c-axis resistivity rhoc, it depends only very weakly on pressure and/or intercalate structural order. We show that the behavior observed is consistent with a band conduction model.
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| 2. |
- Andersson, Odd E., et al.
(author)
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The c-axis resistivity for two HOPG-based, first stage CuAl2Cl8 and second stage CuCl2 - graphite intercalation compounds as a function of both pressure and temperature
- 1996
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In: Journal of Physics and Chemistry of Solids, volume 57, issues 6-8. - : Elsevier Ltd.. ; , s. 719-723
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Conference paper (peer-reviewed)abstract
- In this paper we present data for the c-axis resistivity of first stage CuAl2Cl8 GIC and second stage CuCl2 GIC as functions of pressure, p, (0.0 < p < 1.5 GPa) and of temperature, T, (4 < T < 300 K). We show evidence of a possible new high-pressure phase above 1.0 GPa for the CuAl2Cl8 GIC and we show that the CuCl2 GIC is very stable at all pressures and temperature investigated. We make a comparison with previous results on SbCl5 GICs and other chloride intercalation compounds and with theories treating the temperature and pressure coefficients of transport parameters in layered solids.
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| 3. |
- Celzard, Alain, et al.
(author)
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Conduction mechanisms in some graphite-polymer composites: effects of temperature and pressure
- 1998
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In: Journal of Applied Physics. - : American Institute of Physics. - 0021-8979 .- 1089-7550. ; 83:3, s. 1410-1419
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Journal article (peer-reviewed)abstract
- This article is devoted to the conduction mechanisms involved in some highly electrically anisotropic resin–graphite particle composites. These materials are known to show a percolation phenomenon as the filler content is varied; they are epoxy or polyurethane based, the conducting particles are oriented single-crystal platelets, and samples are in the form of thick films. Because of their strong anisotropy, two types of measurements were made, i.e., parallel to and perpendicular to the plane of the films. Study of the resistivity variations of samples containing various concentrations in conducting particles was carried out first as a function of temperature from 4.2 to 300 K at ambient pressure, and second as a function of hydrostatic pressure up to 1.2 GPa, at room temperature. As the temperature is varied, the changes in resistivity of all the samples studied (i.e., above percolation threshold) are weak; analysis leads to the conclusion that thermally activated tunneling plays a dominant role above but close to the percolation threshold phic. As a function of pressure, more samples were studied: when the filler content is above phic, resistivity changes are quantitatively in agreement with what is expected from both percolation theory and tunneling; below threshold, the observed behavior is partially attributable to an ionic conduction mechanism throughout the polymer.
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| 4. |
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| 5. |
- Sundqvist, Bertil, et al.
(author)
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A study of temperature and pressure-induced structural and electronic changes in SbCl5 intercalated graphite : Part III. Analysis of the T and p dependence of the c-axis resistivity
- 1995
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In: Journal of Materials Research. - 0884-2914 .- 2044-5326. ; 10:2, s. 436-446
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Journal article (peer-reviewed)abstract
- We present experimental data for the c-axis electrical resistivity of SbCl5 intercalated graphite between 20 and 300 K. The data are analyzed together with our previous results for these and other samples [O. E. Andersson et al., J. Mater. Res. 7, 2989 (1992)]. Before the analysis, we correct the experimental data to constant volume, as assumed by theorists. We show that the correction factor is much larger for these materials than for normal metals. Although the original data showed significant nonlinearities with T, the corrected data are linear in T to within the experimental accuracy for low-stage compounds below the intercalate crystallization temperature. We compare our results with several models and conclude that both the temperature dependence, the pressure dependence, and the relative changes in the in-plane and c-axis resistivities associated with intercalate crystallization can be best described by a band conduction model.
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