| 1. |
- Andersson, Göran, et al.
(författare)
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Pressure dependence of the c-axis resistance of stage 2 SbCl5 intercalated graphite to 4 GPa
- 1988
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Ingår i: Solid State Communications. - : Elsevier BV. - 0038-1098 .- 1879-2766. ; 65:7, s. 735-738
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Tidskriftsartikel (refereegranskat)abstract
- The c-axis electrical resistance R has been measured under pressure up to 4 GPa (40 kbar) at room temperature for stage 2, HOPG-based SbCl5 intercalated graphite. In addition to the well known ordering transition at 0.3–0.5 GPa a second anomaly in R is observed above 1 GPa, corresponding to a further phase transition which is not completed until above 2.4 GPa. In all phases R depends more strongly on p for the intercalated material than for HOPG, and the total decrease in R is over 80% to 4 GPa.
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| 2. |
- Jacobsson, Per, et al.
(författare)
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Pressure dependence of the thermal and electrical conductivities of the intermetallic compounds AuCu and AuCu3
- 1988
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Ingår i: Journal of Physics and Chemistry of Solids. - : Elsevier BV. - 0022-3697 .- 1879-2553. ; 49:4, s. 441-450
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Tidskriftsartikel (refereegranskat)abstract
- The thermal diffusivity, a, electrical resistivity, ρ, and Seebeck coefficient, S, of ordered and disordered AuCu3 and AuCu have been measured as functions of T and P in the range 100–300 K and 0–2 GPa, and the thermal conductivity, λ, has been calculated from the data for a. The experimental data for ρ agree well with literature data. The ρ dependence of ρ and λ differs significantly between ordered and disordered specimens, but apart from the effect of impurity scattering the disordered materials behave much like the noble metals. For the temperature-dependent part of p (and λ) the P dependence differs by a factor of 2–3 between ordered and disordered states. This is shown to result from the difference in electron band structure, as reflected also in the thermoelectric parameter ξ. The P dependence of the relatively large lattice thermal conductivity of these materials causes the Lorenz ratio L = λρ/T to increase with ρ in all cases.
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| 3. |
- Jacobsson, Per, et al.
(författare)
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Thermal conductivity and Lorenz function of zinc under pressure
- 1988
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Ingår i: International journal of thermophysics. - 0195-928X .- 1572-9567. ; 9:4, s. 577-585
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Tidskriftsartikel (refereegranskat)abstract
- The thermal conductivity lambda and the Lorenz function L of polycrystalline zinc have been calculated from measured values of the thermal diffusivity a and the electrical resistivity gamma as functions of pressure P up to 2 GPa at room temperature. The effects of convection in, and freezing of, the pressure transmitting medium are discussed. Both lambda and L increase with increasing P, with pressure coefficients of 8.7×10–2 and 1.5×10–2 GPa–1, respectively. The volume dependence of L is found to be similar to that found for other simple metals. Data are also given for the Seebeck coefficient S as a function of P and for a(T) and lambda(T) between 55 and 300 K.
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| 4. |
- Sundqvist, Bertil
(författare)
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C-axis resistance of stage 2 SbCl5 intercalated graphite under pressure
- 1988
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Ingår i: Synthetic Metals, volume 23. - : Elsevier B.V.. ; , s. 345-350
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Konferensbidrag (refereegranskat)abstract
- The c-axis resistance R of stage 2 SbCl5 intercalated graphite has been measured in the range 80–300 K and 0–4 GPa. The pressure dependence of R is similar to that of HOPG in the ordered low-T phase below 200 K but significantly larger at 300 K, where the initial pressure coefficient of R is −1.37 GPa−1. Two phase transitions are always observed under pressure, one at 0.3–0.5 GPa and one above 1 GPa. The latter is not completed until above 2.4 GPa and both are slow, with large time-dependent effects in R. R decreases by over 80% to 4 GPa.
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| 5. |
- Sundqvist, Bertil
(författare)
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Electrical resistance of nickel in the range 300-725 K and 0-2 GPa
- 1988
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 38:17, s. 12283-12289
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Tidskriftsartikel (refereegranskat)abstract
- The electrical resistance R of Ni has been measured as a function of temperature T and pressure p over the range 300–725 K and 0–2 GPa (0–20 kbar). In contrast to recent reports, we see no anomalies in R(p) at 300 K, and we see no change in sign in dR/dp at the Curie temperature TC. The pressure coefficient of R was -1.82×10-2 GPa-1 at 300 K, increasing with T to a peak value of -2.5×10-2 GPa-1 at TC, above which it rapidly decreased to a value 20% below the room-temperature value. The data are analyzed using simple models; the resistivity at constant volume is found to deviate significantly from the constant-p data above TC and a small anomaly is detected in d(lnR)/dp that could possibly be an effect of band-structure changes at TC.
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| 6. |
- Sundqvist, Bertil
(författare)
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Electrical resistance of YBa2Cu3O7-delta in the range 300-500 K and 0-1.5 GPa
- 1988
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Ingår i: Solid State Communications. - : Elsevier BV. - 0038-1098 .- 1879-2766. ; 66:6, s. 623-627
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Tidskriftsartikel (refereegranskat)abstract
- The electrical resistance R of single-phase, sintered YBa2Cu3O7−δ has been studied as a function of pressure p and temperature T in the range 300 to 500 K and 0 to 1.5 GPa (15 kbar). R is linear in T and has an initial pressure coefficient of about −13 %/GPa. The pressure dependence of Tc has also been measured up to 1 GPa, with the result dTc/dp = 0.45 K/GPa. The results are discussed in terms of electron-electron scattering, electron-phonom scattering, and the resonating valence bond theory, but none of these can fully explain the results.
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