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Bulletin of the Korean Chemical Society (BKCS)

ISSN 0253-2964(Print)
ISSN 1229-5949(Online)
Volume 18, Number 7
BKCSDE 18(7)
July 20, 1997 

 
Title
Local Structure Refinement of the BaFe1-xSnxO3-y System with Fe K-Edge X-Ray Absorption (XANES/EXAFS) Spectroscopy
Author
Min Gyu Kim, Ki Seop Kwack, Kwon Sun Roh, Chul Hyun Yo*
Keywords
Abstract
Local structure refinement of the BaFe1-xSnxO3-y system (x=0.00-0.50) has been carried out with Fe K-edge x-ray absorpion spectroscopic studies. It is found out that the Fe ions are placed in two different symmetric sites such as tetrahedral and octahedral sites in the compounds by comparison with Fe K-edge x-ray absorption near edge structure (XANES) spectrum of the γ-Fe2O3 compound as a reference. Small absorption peaks of dipole-forbiden transitions appear at a pre-edge region of 7111 eV due to the existence of Fe ions in the tetrahedral and octahedral sites. The peak intensity decreases with the substitution amount of Sn ion. Three different absorption peaks of 1s→4p dipole-allowed transition appear on the energy region between 7123 and 7131 eV. The peaks correspond to 1s→4p main transition of Fe ions in tetrahedral and octahedral sites and 1s→4p transition followed by the shakedown process of ligand to metal charge transfer. The bond distances between Fe ions in the tetrahedral site and nearest neighboring oxygen atom (Fe-4O), and those in octahedral site (Fe-6O) are determined with the extended x-ray absorption fine structure (EXAFS) analysis. Two different interatomic distances increase with the substitution amount of Sn ion and also the bond lengths of Fe-4O are shorter than those of Fe-6O in all compounds.
Page
743 - 748
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