Solid state (47,49)Ti, (87)Sr and (137)Ba NMR characterisation of mixed barium/strontium titanate perovskites.
Solid state (47,49)Ti, (137)Ba, (87)Sr NMR spectra have been recorded on BaxSrl-xTiO3 (0 </= x </=1) perovskite samples prepared by the powder sintering method. Multinuclear solid state NMR shows great potential for characterising such systems since the quadrupolar parameters are very sensitive to any geometric deformation around the studied nucleus. (47,49)Ti NMR powder lineshapes appear strongly influenced by the presence of even a small amount of barium (or strontium) in the coordination second sphere of the probed titanium site: substitution of strontium by barium induces the broadening of the peaks, due to quadrupolar effects, while the isotropic chemical shift increases. (137)Ba NMR spectra exhibit a distribution of the quadrupolar interaction, that could be tentatively quantified, CQ increasing with the amount of strontium. Preliminary results were also obtained on (87)Sr NMR showing behaviour comparable to (137)Ba NMR, i.e. a broadening of the peaks due to an increasing quadrupolar interaction with the amount of barium distorting the environment of the strontium sites.
Gervais
Christel
C
Chimie de la Matière Condensée, Université Pierre et Marie Curie, 4 place Jussieu, 75252 Paris, France. gervais@ccr.jussieu.fr
Veautier
Delphine
D
Smith
Mark E
ME
Babonneau
Florence
F
Belleville
Philippe
P
Sanchez
Clément
C