Presentation Information
[8p-N201-2]Dependence of Electronic States and Electrical Conductivity on Local Atomic Arrangement and La Substitution in Layered Oxide Sr2.5Bi0.5NiO5
〇(M2)Yuxin Peng1, Hideyuki Kawasoko1, Soichi Kikkawa1, Seiji Yamazoe1 (1.Tokyo Metropolitan Univ.)
Keywords:
Transition metal oxide,Local atomic arrangement,X-ray Absorption Near Edge Structure
Sr2.5Bi0.5NiO5 is a unique oxide in which the ordering/disordering of Sr/Bi arrangement in the (Sr1.5Bi0.5)O2 rock-salt-type insulating layer is strongly correlated with its electrical conduction.
In this study, the effect of La substitution at the Sr site on the crystal structure and electronic state was investigated for both ordered and disordered phases of Sr2.5Bi0.5NiO5.X-ray diffraction and Rietveld analysis revealed that, regardless of the Sr/Bi ordering, the a-axis length decreases while the c-axis length increases with increasing La substitution. The solubility limit of La was also found to be 15%.
Furthermore, X-ray absorption Near Edge structure (XANES) measurements showed that, in the ordered phase, La substitution induces a reduction in the Ni valence, while in the disordered phase, the Ni valence shifts towards oxidation.These results suggest that, even with the same La substitution, differences in Sr/Bi ordering may have distinct effects on the electronic properties of Sr2.5Bi0.5NiO5.
In this study, the effect of La substitution at the Sr site on the crystal structure and electronic state was investigated for both ordered and disordered phases of Sr2.5Bi0.5NiO5.X-ray diffraction and Rietveld analysis revealed that, regardless of the Sr/Bi ordering, the a-axis length decreases while the c-axis length increases with increasing La substitution. The solubility limit of La was also found to be 15%.
Furthermore, X-ray absorption Near Edge structure (XANES) measurements showed that, in the ordered phase, La substitution induces a reduction in the Ni valence, while in the disordered phase, the Ni valence shifts towards oxidation.These results suggest that, even with the same La substitution, differences in Sr/Bi ordering may have distinct effects on the electronic properties of Sr2.5Bi0.5NiO5.