| 1. |
- Forsberg, Johan, et al.
(författare)
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System for in situ studies of atmospheric corrosion of metal films using soft x-ray spectroscopy and quartz crystal microbalance
- 2007
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Ingår i: Review of Scientific Instruments. - : AIP Publishing. - 0034-6748 .- 1089-7623. ; 78:8
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Tidskriftsartikel (refereegranskat)abstract
- We present a versatile chamber (atmospheric corrosion cell) for soft x-ray absorption/emission spectroscopy of metal surfaces in a corrosive atmosphere allowing novel in situ electronic structure studies. Synchrotron x rays passing through a thin window separating the corrosion cell interior from a beamline vacuum chamber probe a metal film deposited on a quartz crystal microbalance (QCM) or on the inside of the window. We present some initial results on chloride induced corrosion of iron surfaces in humidified synthetic air. By simultaneous recording of QCM signal and soft x-ray emission from the corroding sample, correlation between mass changes and variations in spectral features is facilitated.
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| 2. |
- Forsberg, J., et al.
(författare)
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The initial stages of atmospheric corrosion of iron in a saline environment studied with time-resolved in situ x-ray transmission microscopy
- 2010
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Ingår i: Journal of the Electrochemical Society. - : The Electrochemical Society. - 0013-4651 .- 1945-7111. ; 157:3, s. C110-C115
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Tidskriftsartikel (refereegranskat)abstract
- We have investigated atmospheric corrosion of a 50 nm layer of iron covered with a thin layer of NaCl by in situ X-ray transmission spectromicroscopy. We find that upon its deliquescence, a small part of the NaCl layer is rapidly transformed into a sodium oxide (NaOH) species. A large part of the sodium and chlorine ions forms a concentrated solution on the iron surface and becomes segregated, whereby the sodium ions appear stationary and passive during further corrosion progression. In contrast, the chlorine ions appear highly mobile and become concentrated at and travel with the corrosion front, apparently acting as a corrosion catalyst. The corrosion front progression is partly of filiform and partly of radial type. The early iron corrosion products (chloride-containing oxyhydroxides) are short-lived (for some hours) and undergo a transformation as the corrosion front sweeps by from a chlorinated species to a less chlorinated species.
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| 3. |
- Glawion, S., et al.
(författare)
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Two-Spinon and Orbital Excitations of the Spin-Peierls System TiOCl
- 2011
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 107:10, s. 107402-
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Tidskriftsartikel (refereegranskat)abstract
- We combine high-resolution resonant inelastic x-ray scattering with cluster calculations utilizing a recently derived effective magnetic scattering operator to analyze the polarization, excitation energy, and momentum-dependent excitation spectrum of the low-dimensional quantum magnet TiOCl in the range expected for orbital and magnetic excitations (0-2.5 eV). Ti 3d orbital excitations yield complete information on the temperature-dependent crystal-field splitting. In the spin-Peierls phase we observe a dispersive two-spinon excitation and estimate the inter- and intradimer magnetic exchange coupling from a comparison to cluster calculations.
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| 4. |
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| 5. |
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| 6. |
- Learmonth, T., et al.
(författare)
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Observation of multiple Zhang-Rice excitations in a correlated solid : Resonant inelastic X-ray scattering study of Li2CuO2
- 2007
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Ingår i: Europhysics letters. - : IOP Publishing. - 0295-5075 .- 1286-4854. ; 79:4, s. 47012-
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Tidskriftsartikel (refereegranskat)abstract
- Multiple Zhang-Rice type spectral features have been observed in resonant inelastic X-ray scattering (RIXS) from the quasi -one-dimensional cuprate charge transfer insulator Li2CuO2. The first feature appears at constant emission energy, and is associated with a Zhang-Rice singlet final state. The second is an interplaquette charge transfer excitation that results in a novel triplet Zhang-Rice -type final state. It is accompanied by the presence of a O 2p nonbonding to upper Hubbard band excitation at an energy close to that of a calculated triplet charge transfer Zhang-Rice -type excitation. The site selectivity and polarization rules associated with RIXS allows these two excitations to be distinguished.
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| 7. |
- Magnuson, Martin, et al.
(författare)
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Self-doping processes between planes and chains in the metal-to-superconductor transition of YBa2Cu3O6.9
- 2014
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 4, s. 7017-
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Tidskriftsartikel (refereegranskat)abstract
- The interplay between the quasi 1-dimensional CuO-chains and the 2-dimensional CuO2 planes of YBa2Cu3O61x (YBCO) has been in focus for a long time. Although the CuO-chains are known to be important as charge reservoirs that enable superconductivity for a range of oxygen doping levels in YBCO, the understanding of the dynamics of its temperature-driven metal-superconductor transition (MST) remains a challenge. We present a combined study using x-ray absorption spectroscopy and resonant inelastic x-ray scattering (RIXS) revealing how a reconstruction of the apical O(4)-derived interplanar orbitals during the MST of optimally doped YBCO leads to substantial hole-transfer from the chains into the planes, i.e. self-doping. Our ionic model calculations show that localized divalent charge-transfer configurations are expected to be abundant in the chains of YBCO. While these indeed appear in the RIXS spectra from YBCO in the normal, metallic, state, they are largely suppressed in the superconducting state and, instead, signatures of Cu trivalent charge-transfer configurations in the planes become enhanced. In the quest for understanding the fundamental mechanism for high-Tc-superconductivity (HTSC) in perovskite cuprate materials, the observation of such an interplanar self-doping process in YBCO opens a unique novel channel for studying the dynamics of HTSC.
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