Hole doping in high temperature superconductors using the XANES technique

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Superconducting and physical properties of F-doped HgPb-1223 and Ce-doped Tl-1223 systems were considerably improved through adjusting the hole content of the two systems. In this study, we have used the x-ray absorption near-edge structure (XANES) technique to investigate the electronic structure of the two systems by probing the unoccupied electronic states. For the F-doped Hg-1223 system, the O K-edge, Ca L{sub 2,3} and Cu L{sub 2,3}-edge structures were thoroughly investigated. The pre-edge features of O K-edge spectra, as a function of doping, reveal important information about the projected local density of unoccupied states on the O sites in the region ... continued below

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Hamdan, Nasser & Hussain, Zahid September 1, 2008.

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Superconducting and physical properties of F-doped HgPb-1223 and Ce-doped Tl-1223 systems were considerably improved through adjusting the hole content of the two systems. In this study, we have used the x-ray absorption near-edge structure (XANES) technique to investigate the electronic structure of the two systems by probing the unoccupied electronic states. For the F-doped Hg-1223 system, the O K-edge, Ca L{sub 2,3} and Cu L{sub 2,3}-edge structures were thoroughly investigated. The pre-edge features of O K-edge spectra, as a function of doping, reveal important information about the projected local density of unoccupied states on the O sites in the region close to the absorption edge, which is a measure of O 2p hole concentration in the valence band. In the originally under-doped Hg-1223, the results indicate that the number of O 2p holes in the CuO{sub 2} planes increases as fluorine was introduced up to an optimal value, after which it decreases. Furthermore, the Cu L{sub 2,3} absorption edge provides useful information about the valence state of Cu which is also related to the hole density in the CuO{sub 2} planes and confirms the same previous conclusion. The Ca L{sub 2,3}-edge shows the presence crystal field splitting in HgPb1223/F{sub x} which is similar to CaF{sub 2} and CaO in addition to the spin-orbit splitting of the Ca 2p core level electrons. These results ensure that fluorine goes into the structure of HgPb-1223/F{sub x} and it occupies the vacant interstitial oxygen site in the Hg-O plane, as was expected. In Ce-substituted Tl-1223, similar measurements were perfonned for samples with different Ce content. The pre-edge feature of the O K-edge spectra shows clearly the drastic decrease of the hole content in CuO{sub 2} planes of this originally over-doped system with increasing Ce content. This result is also confirmed from the chemical state of Ce in the structure as obtained from the Ce M{sub 4,5}-edge spectra.

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  • Journal Name: Superconductor Science and Technology; Journal Volume: 22; Journal Issue: 3; Related Information: Journal Publication Date: 1/28/2009

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  • Report No.: LBNL-4729E
  • Grant Number: DE-AC02-05CH11231
  • DOI: 10.1088/0953-2048/22/3/034007 | External Link
  • Office of Scientific & Technical Information Report Number: 1032517
  • Archival Resource Key: ark:/67531/metadc833131

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Reports, articles and other documents harvested from the Office of Scientific and Technical Information.

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  • September 1, 2008

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  • May 19, 2016, 3:16 p.m.

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  • July 28, 2016, 1:07 p.m.

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Hamdan, Nasser & Hussain, Zahid. Hole doping in high temperature superconductors using the XANES technique, article, September 1, 2008; Berkeley, California. (digital.library.unt.edu/ark:/67531/metadc833131/: accessed January 23, 2018), University of North Texas Libraries, Digital Library, digital.library.unt.edu; crediting UNT Libraries Government Documents Department.