| 1. |
- Minnhagen, Petter
(författare)
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Increased phonon broadening of XPS lines of metals due to finite core-hole lifetime
- 1976
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Ingår i: Journal of Physics F: Metal Physics. - : IOP Publishing. - 0305-4608. ; 6:10, s. 800-1789
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Tidskriftsartikel (refereegranskat)abstract
- The author generalizes the solution of the independent boson model to take the finite lifetime of the core hole into account. The generalized solution is compared to the conventional convolution of the infinite lifetime spectral function with a Lorentzian lifetime broadening function. The generalized solution reduces to the conventional convolution in two limits. However, the new solution predicts appreciable phonon broadening for simple metals. Rough estimates of this new effect are compared with recent experimental results on XPS lines.(12 refs)
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| 2. |
- Minnhagen, Petter
(författare)
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On the quantitative evaluation of XPS lineshape asymmetries for free-electron-like metals
- 1977
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Ingår i: Journal of Physics F: Metal Physics. - : IOP Publishing. - 0305-4608. ; 7:11, s. 2441-2450
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Tidskriftsartikel (refereegranskat)abstract
- It is demonstrated that an accurate approximation of the screening function is crucial for a quantitative evaluation of the XPS asymmetry index α. It is also shown that the dynamical aspects of the valence electron response are important in order to get an accurate description of the XPS spectrum at finite distances from the threshold.(23 refs)
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| 3. |
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| 4. |
- Malmhall, Roger, et al.
(författare)
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Hall resistivity of a two-phase magnetic material - crystallised Metglas 2826
- 1979
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Ingår i: Journal of Physics F: Metal Physics. - : Institute of Physics (IOP). - 0305-4608. ; 9:2, s. 317-325
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Tidskriftsartikel (refereegranskat)abstract
- Hall resistivity measurements in the temperature range 100-800 K have been used to study the influence of thermal cycling and annealing on amorphous Fe40Ni40P14B6. While the as-received sample has Tc = 510 K. thermal cycling to 700 K yields a two-phase system. one of the phases having a broad transition around 425 K. Annealing for three hours at 800 K causes this transition to sharpen up. and we also observe a second transition at 730 K. The extraordinary Hall coefficient (R1) has been analysed and is described in terms of linear contributions from each phase. From simultaneous measurements of the ohmic resistivity ρ on the same sample it is found that, for the two-phase material. R1 is related to ρ as R1 = aρ + bρ2 for 100 < K < 300 K. In the amorphous state there is an anomaly in ρ at Tc. From the relationship between R1(T) and ρ(T) it is concluded that in both amorphous and crystallised materials the side jump is of the same order of magnitude as in dilute Fe alloys.
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| 5. |
- Sundqvist, Bertil, et al.
(författare)
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Measurement of the pressure dependence of the electron-phonon interaction in aluminium
- 1979
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Ingår i: Journal of Physics F: Metal Physics. - Bristol : Institute of Physics. - 0305-4608. ; 9:9, s. L161-L166
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Tidskriftsartikel (refereegranskat)abstract
- The authors report measurements of the electrical resistance of aluminium in the temperature range 30-40 degrees C and the pressure range 0.2-1.0 GPa. From these experiments the pressure dependence of the electron-photon interaction lambda is evaluated. With p in GPa the result is lambda (p)= lambda 0 exp(-0.0467p+4.7*10-4 p2). This expression for lambda describes accurately the observed pressure dependence of the superconducting Tc for pressures up to about 4 GPa.
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| 6. |
- Almbladh, Carl-Olof, et al.
(författare)
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Phonon effects on deep-level excitations in metals: Beyond the linear-screening and linear-coupling models
- 1985
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Ingår i: Journal of Physics F: Metal Physics. - 0305-4608. ; 15:4, s. 991-1012
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Tidskriftsartikel (refereegranskat)abstract
- New theoretical developments in impurity lattice dynamics are presented, with the emphasis on phonon broadening of core levels in metals. Detailed calculations have been made for Li and Na. The effects of non-linear screening are evaluated for the first time and are shown to increase the phonon broadening by about 70% for Li compared with the linear-screening value. The present a priori estimate of the phonon broadening of the Li 1s level is the first which agrees with experiment. The effects of core-hole-lattice couplings of second order in ion displacements are also evaluated and shown to be unimportant for Li and Na. The usual linear-screening theory for lattice dynamics and for impurity-lattice couplings is analysed critically with regard to its sensitivity to the approximations for the pseudopotential and for the screening function. Both optimised model potentials and norm-conserving a priori potentials are considered. Finally, an indirect phonon broadening mechanism proposed previously is analysed and shown to give a negligible effect.
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| 7. |
- Hedin, Lars, et al.
(författare)
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On temperature broadening in X-ray spectra of metals
- 1977
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Ingår i: Journal of Physics F: Metal Physics. - 0305-4608. ; 7:7, s. 1339-1348
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Tidskriftsartikel (refereegranskat)abstract
- Calculates the full width at half maximum (FWHM) of the phonon broadening function for Li, Na, K and Al at different temperatures. A theory is used which employs the ionic pseudopotential, rather than, as in Bergersen et al's (1971) theory, a bare Coulomb potential. Despite the fact that a pseudopotential in a general sense is weaker than a Coulomb potential the authors find that the former gives considerably larger FWHM's, e.g. in Li at T=0 the FWHM becomes more that doubled. They also discuss other broadening effects and conclude that their results are consistent with recent experimental data presented by Baer et al. (1976).
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