| 1. |
- Jarlborg, Thomas, et al.
(författare)
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Electron-Phonon Interaction of fcc and dhcp La under Pressure
- 1987
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Ingår i: Japanese Journal of Applied Physics, volume 26, Supplement 26-3-2. - : The Japan Society of Applied Physics. ; , s. 919-920
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Konferensbidrag (refereegranskat)abstract
- The pressure dependence of the electron-phonon interaction of La has been studied for both phases by two methods: One is a calculation of λ and the other uses the calculated plasma frequency and the measured temperature and pressure dependence of the electrical resistivity. These results as well as a calculation of the spin-fluctuation contribution suggest that quenching of spin-fluctuations with pressure contribute to the increase of Tc with pressure in La.
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| 2. |
- Sundqvist, Bertil
(författare)
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Low T hydrostatic limits of n-pentane/iso-pentane mixture measured by a self-supporting Manganin pressure gauge
- 1987
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Ingår i: Journal of Physics. E, Scientific Instruments. - Bristol : Institute of Physics. - 0022-3735. ; 20:8, s. 984-986
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Tidskriftsartikel (refereegranskat)abstract
- A simple design for a self-supporting Manganin pressure gauge is described. The shear-strain sensitivity of the gauge has been used to determine the hydrostatic pressure limit below 150 K of the 50/50 mixture by volume of n- and isopentane that is commonly used as a pressure-transmitting medium in high-pressure experiments.
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| 3. |
- Sundqvist, Bertil, et al.
(författare)
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Pressure-temperature phase diagrams of stage-2-4 potassium-graphite intercalation compounds deduced from anomalies in the basal plane resistivity
- 1987
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 35:15, s. 8231-8242
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Tidskriftsartikel (refereegranskat)abstract
- The basal-plane resistivities ρ of stage-2–4 potassium-graphite intercalation compounds (K-GIC’s) have been measured as functions of temperature T and pressure p using a contactless method. The pressure range investigated was 0–1.4 GPa. For stage-2 K-GIC (KC24) measurements were made in the temperature range 90–300 K, while for the higher-stage materials the range was mainly limited to 245–300 K. In all cases ρ increases with p through the anomalous regime near the phase transitions, whereas dρ/dp is always negative in the stable high-p (high-stage) phases. Approximate p-T phase diagrams are deduced from anomalies in ρ corresponding to the staging and in-plane order-disorder transitions, respectively. In all cases the slopes dp/dT of the phase boundaries for the high-pressure staging transitions are such that the transitions extrapolate to positive T at atmospheric p, although no such transitions have been reported. The low-p staging-ordering phase boundary of KC24 is particularly complex, involving segments with both dp/dT→0 (125<200 K) and dp/dT→∞ (T≊125 K). The p-T diagrams are compared with recent structural experiments and models. We suggest that the complexity of the KC24 phase diagram is attributable to the weakly incommensurate in-plane structure at low p and T.
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