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Ito, Takanori*; Shirasaki, Saori*; Fujie, Yoshinori*; Kitamura, Naoto*; Idemoto, Yasushi*; Osaka, Keiichi*; Hirosawa, Ichiro*; Igawa, Naoki
Denki Kagaku Oyobi Kogyo Butsuri Kagaku, 77(2), p.161 - 168, 2009/02
Times Cited Count:3 Percentile:8.20(Electrochemistry)We analyzed the mechanism of mixed conduction due to electrons and oxygen ions in (LaSr)MnO and (BaSr)(CoFe)O through the Rietveld refinement and maximum entropy method analyses of neutron and synchrotron X-ray diffractions. It was found that Mn-O plane in (LaSr)MnO has a strong, isotropic covalent bond that enables conduction of electrons. The (Co, Fe)-O2 plane with a covalent bond and a low concentration of oxygen vacancies in (BaSr)(CoFe)O can also conduct electrons. On the other hand, the (Ba, Sr)-O1 plane in (BaSr)(CoFe)O, which has a high concentration of oxygen vacancies, large isotropic displacement parameter, and a strong ionic bond, is responsible for the diffusion of oxygen ions.
Ito, Takanori*; Nishida, Yuki*; Tomita, Aya*; Fujie, Yoshinori*; Kitamura, Naoto*; Idemoto, Yasushi*; Osaka, Keiichi*; Hirosawa, Ichiro*; Igawa, Naoki
Solid State Communications, 149(1-2), p.41 - 44, 2009/01
Times Cited Count:36 Percentile:77.47(Physics, Condensed Matter)The crystal structure and charge density of (BaSr)(CoFe)O were investigated by the Rietveld refinement method and the maximum entropy method by using neutron and synchrotron X-ray diffraction. The crystal structure was refined by using the split atom model to cation sites with the space group, . The site occupancies of O1(4) and O2(8) sites were 0.59 and 0.87, respectively. It was found that the (Co, Fe)-O2 plane in the sample has anisotropic covalent and ionic bands, and that the (Ba, Sr)-O1 bond was ionic with a low charge density.