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SUMMARY:NMR of Vacancies: Defect Structures and Mobility in Doped Perovski
 tes and Related Phases - Frédéric Blanc (Department of Chemistry)
DTSTART:20101025T150000Z
DTEND:20101025T160000Z
UID:TALK26580@talks.cam.ac.uk
CONTACT:Ian Farnan
DESCRIPTION:Solid state NMR spectroscopy has been used to investigate the 
 local structure and \nmobility of a series of doped perovskite ABO3 for us
 e as electrolyte materials in solid \noxide fuel cells.1 Both materials th
 at function via oxygen anion O2- or proton H+ transport \nwill be investig
 ated. To induce anionic and protonic motions\, crystallographic defects in
  \nthese materials are needed and are obtained by substitution of metal ca
 tions Mn+ by \nlower valence cations M(n-1)+ in the same crystallographic 
 site. 2\,3 Observation of any \nlocal defects and clustering nearby the de
 fects using diffraction based-techniques is \nthus not straightforward. Wh
 ile the defects cannot be observed directly by NMR\, we will \nshow that w
 e can perform both experimental and computational multinuclear solid state
  \nNMR spectroscopy analysis to determine the coordination environment of 
 the metals \nand thus locate the oxygen defects.4-6 Preliminary results on
  the direct observation of \nanionic O2- and protonic H+ motions will also
  be demonstrated. The application of the \napproach to investigate Sr- and
  Mg-doped LaMO3 (M = Ga\, Al)\, and Y/Sc doped BaMO3 \n(M = Zr\, Sn) perov
 skites will be presented.   \n \n \nReferences: \n(1) Ishihara\, T. Perovs
 kite Oxide for Solid Oxide Fuel Cells\; Springer: Boston\, 2002. \n(2) Boi
 vin\, J. C.\; Mairesse\, G. Chem. Mater. 1998\, 10\, 2870. \n(3) Kreuer\, 
 K. D. Ann. Rev. Mat. Res. 2003\, 33\, 333. \n(4) Middlemiss\, D. S.\; Blan
 c\, F.\; Grey\, C. P. E. C. S. Transactions 2009\, 25\, 1709. \n(5) Middle
 miss\, D. S.\; Blanc\, F.\; Pickard\, C. J.\; Grey\, C. P. J Magn Reson 20
 10\, 204\, 1. \n(6) Buannic\, L.\; Blanc\, F.\; Hung\, I.\; Gan\, Z.\; Gre
 y\, C. P. J. Mat. Chem. 2010\, 20\, 6322. \n
LOCATION:Harker 2 lecture room\, Department of Earth Sciences\, Downing Si
 te
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