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Electronic structure of AgNbO3 single crystals
|Ewa Talik , Magdalena Kruczek , Antoni Kania|
University of Silesia, Katowice, Poland
The electronic structure of niobiates attracts attention due to interesting ferroelectric and relaxor characteristic. Moreover AgNbO3 has arisen as a new visible-light-driven photocatalyst. The XPS electronic structure measurements of the AgNbO3 single crystals were performed. The results were compared with those obtained for the NaNbO3 ceramic. The chemical composition determined by the XPS method is Ag1.1Nb0.93O2.97. The core level measurements revealed a smaller negative chemical shift of the Ag 3d line (-0.3 eV) in comparison with Na (-1.1 eV). The positive chemical shift of Nb 3d line +4.2 eV is in agreement with those obtained for the Nb 3d in NaNbO3. The chemical shift of the O 1s line is -1.3 eV for AgNbO3 and -1.8 eV for NaNbO3. These results suggest a mixed covalent and ionic bonding in the compounds. The covalent character of the bonds is between Ag (or Na) and oxygen and while the ionic with Nb. The valence band exhibits the energy gap about 2 eV which is in agreement with literature data.
Presentation: poster at E-MRS Fall Meeting 2004, Symposium I, by Ewa Talik
See On-line Journal of E-MRS Fall Meeting 2004
Submitted: 2004-05-27 13:07 Revised: 2009-06-08 12:55