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Ag-Cu oxide nanoparticles with high oxidation states : towards new high Tc materials

Tchaplyguine, Maxim LU ; Zhang, Chaofan LU ; Andersson, Tomas LU and Björneholm, Olle LU (2018) In Dalton transactions (Cambridge, England : 2003) 47(46). p.16660-16667
Abstract

In Ag-Cu oxides possible to fabricate so far, superconductivity has not been detected, but high conductivity was. In the quest for superconductivity the demand is to create a high and peculiar copper-oxygen coordination. Such coordination makes it non-trivial to determine Cu oxidation states, which may be several and co-existing. Another reason for uncertainty is in oxygen deficiency typical for superconducting crystals. Finally, Cu oxidation is influenced by the other metals in the substance. For chemical fabrication the difficulty is to tune the relative abundances of elements in a fine way. Ag-Cu oxides have been also produced by reactive co-sputtering of Cu and Ag, but the composition with high Cu oxidation states necessary for high... (More)

In Ag-Cu oxides possible to fabricate so far, superconductivity has not been detected, but high conductivity was. In the quest for superconductivity the demand is to create a high and peculiar copper-oxygen coordination. Such coordination makes it non-trivial to determine Cu oxidation states, which may be several and co-existing. Another reason for uncertainty is in oxygen deficiency typical for superconducting crystals. Finally, Cu oxidation is influenced by the other metals in the substance. For chemical fabrication the difficulty is to tune the relative abundances of elements in a fine way. Ag-Cu oxides have been also produced by reactive co-sputtering of Cu and Ag, but the composition with high Cu oxidation states necessary for high conductivity has not been realized. In the present work we have fabricated Ag-Cu-oxide nanoparticles containing Cu and Ag in high oxidation states actual for superconductivity. The fabrication includes reactive sputtering of Ag and Cu metals, their vapour oxidation and aggregation into nanoparticles. The ability to create different and high oxidation states, also co-existing, is demonstrated. The fabrication approach also allows overcoming the poor miscibility of Cu and Ag. The nanoparticle composition and the oxidation states could be determined due to an experimental arrangement in which photoelectron spectroscopy is applied to free nanoparticles in a beam in vacuum, what allows avoiding any contact of the particles to a substrate or atmosphere. The combination of the fabrication and characterization methods has proven to be a powerful approach when fine composition tuning and control are desirable.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Dalton transactions (Cambridge, England : 2003)
volume
47
issue
46
pages
8 pages
publisher
Royal Society of Chemistry
external identifiers
  • scopus:85057183636
ISSN
1477-9234
DOI
10.1039/c8dt04118k
language
English
LU publication?
yes
id
664199fc-6793-40cd-b4ff-b59b2cc66053
date added to LUP
2018-12-03 13:36:10
date last changed
2019-02-20 11:38:37
@article{664199fc-6793-40cd-b4ff-b59b2cc66053,
  abstract     = {<p>In Ag-Cu oxides possible to fabricate so far, superconductivity has not been detected, but high conductivity was. In the quest for superconductivity the demand is to create a high and peculiar copper-oxygen coordination. Such coordination makes it non-trivial to determine Cu oxidation states, which may be several and co-existing. Another reason for uncertainty is in oxygen deficiency typical for superconducting crystals. Finally, Cu oxidation is influenced by the other metals in the substance. For chemical fabrication the difficulty is to tune the relative abundances of elements in a fine way. Ag-Cu oxides have been also produced by reactive co-sputtering of Cu and Ag, but the composition with high Cu oxidation states necessary for high conductivity has not been realized. In the present work we have fabricated Ag-Cu-oxide nanoparticles containing Cu and Ag in high oxidation states actual for superconductivity. The fabrication includes reactive sputtering of Ag and Cu metals, their vapour oxidation and aggregation into nanoparticles. The ability to create different and high oxidation states, also co-existing, is demonstrated. The fabrication approach also allows overcoming the poor miscibility of Cu and Ag. The nanoparticle composition and the oxidation states could be determined due to an experimental arrangement in which photoelectron spectroscopy is applied to free nanoparticles in a beam in vacuum, what allows avoiding any contact of the particles to a substrate or atmosphere. The combination of the fabrication and characterization methods has proven to be a powerful approach when fine composition tuning and control are desirable.</p>},
  author       = {Tchaplyguine, Maxim and Zhang, Chaofan and Andersson, Tomas and Björneholm, Olle},
  issn         = {1477-9234},
  language     = {eng},
  number       = {46},
  pages        = {16660--16667},
  publisher    = {Royal Society of Chemistry},
  series       = {Dalton transactions (Cambridge, England : 2003)},
  title        = {Ag-Cu oxide nanoparticles with high oxidation states : towards new high T<sub>c</sub> materials},
  url          = {http://dx.doi.org/10.1039/c8dt04118k},
  volume       = {47},
  year         = {2018},
}