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Defect and electrical transport properties of Nb-doped SrTiO3

Blennow Tullmar, Peter LU ; Hagen, Anke; Hansen, Kent K.; Wallenberg, Reine LU and Mogensen, Mogens (2008) In Solid State Ionics 179(35-36). p.2047-2058
Abstract
This study reports the defect and electrical transport properties of Nb-doped SrTiO3, Samples with various A/B-ratios were synthesized by a modified glycine-nitrate combustion process and evaluated as a constituent in a SOFC anode. The phase purity and defect structure of the materials have been analyzed with SEM, XRD, TGA, and XANES. The electrical conductivity of Nb-doped strontium titanate (Sr0.94Ti0.9Nb0.1O3 - sintered in 9% H-2/N-2 at 1400 degrees C for 12 h) decreased with increasing temperature and showed a phonon scattering conduction mechanism with (sigma>120 S/cm at 1000 degrees C (in 9% H-2/N-2). The results were in agreement with the defect chemistry model of donor-doped SrTiO3 where the charge compensation changes from Sr... (More)
This study reports the defect and electrical transport properties of Nb-doped SrTiO3, Samples with various A/B-ratios were synthesized by a modified glycine-nitrate combustion process and evaluated as a constituent in a SOFC anode. The phase purity and defect structure of the materials have been analyzed with SEM, XRD, TGA, and XANES. The electrical conductivity of Nb-doped strontium titanate (Sr0.94Ti0.9Nb0.1O3 - sintered in 9% H-2/N-2 at 1400 degrees C for 12 h) decreased with increasing temperature and showed a phonon scattering conduction mechanism with (sigma>120 S/cm at 1000 degrees C (in 9% H-2/N-2). The results were in agreement with the defect chemistry model of donor-doped SrTiO3 where the charge compensation changes from Sr vacancy compensation to the electronic type when samples are sintered in reducing atmosphere. XANES in combination with TGA indicated that Ti is the only species that is reduced to a lower oxidation state (from Ti4+ to Ti3+). The pre-edge fine structure (PEFS) from the XANES results indicated that Nb improved the overlap of the Ti atomic orbitals and thereby provided one more explanation for the positive effect of Nb on the electronic conductivity of Nb-doped SrTiO3. (C) 2008 Elsevier B.V. All rights reserved. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Conductivity, Nb-doped SrTiO3, Defect chemistry, XANES, XRD
in
Solid State Ionics
volume
179
issue
35-36
pages
2047 - 2058
publisher
Elsevier
external identifiers
  • wos:000261904800017
  • scopus:56349104442
ISSN
0167-2738
DOI
10.1016/j.ssi.2008.06.023
language
English
LU publication?
yes
id
5378ccdf-8339-4a40-876a-fdb9df0e9786 (old id 1376346)
date added to LUP
2009-04-24 11:27:28
date last changed
2017-10-01 03:48:03
@article{5378ccdf-8339-4a40-876a-fdb9df0e9786,
  abstract     = {This study reports the defect and electrical transport properties of Nb-doped SrTiO3, Samples with various A/B-ratios were synthesized by a modified glycine-nitrate combustion process and evaluated as a constituent in a SOFC anode. The phase purity and defect structure of the materials have been analyzed with SEM, XRD, TGA, and XANES. The electrical conductivity of Nb-doped strontium titanate (Sr0.94Ti0.9Nb0.1O3 - sintered in 9% H-2/N-2 at 1400 degrees C for 12 h) decreased with increasing temperature and showed a phonon scattering conduction mechanism with (sigma>120 S/cm at 1000 degrees C (in 9% H-2/N-2). The results were in agreement with the defect chemistry model of donor-doped SrTiO3 where the charge compensation changes from Sr vacancy compensation to the electronic type when samples are sintered in reducing atmosphere. XANES in combination with TGA indicated that Ti is the only species that is reduced to a lower oxidation state (from Ti4+ to Ti3+). The pre-edge fine structure (PEFS) from the XANES results indicated that Nb improved the overlap of the Ti atomic orbitals and thereby provided one more explanation for the positive effect of Nb on the electronic conductivity of Nb-doped SrTiO3. (C) 2008 Elsevier B.V. All rights reserved.},
  author       = {Blennow Tullmar, Peter and Hagen, Anke and Hansen, Kent K. and Wallenberg, Reine and Mogensen, Mogens},
  issn         = {0167-2738},
  keyword      = {Conductivity,Nb-doped SrTiO3,Defect chemistry,XANES,XRD},
  language     = {eng},
  number       = {35-36},
  pages        = {2047--2058},
  publisher    = {Elsevier},
  series       = {Solid State Ionics},
  title        = {Defect and electrical transport properties of Nb-doped SrTiO3},
  url          = {http://dx.doi.org/10.1016/j.ssi.2008.06.023},
  volume       = {179},
  year         = {2008},
}