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Electronic state and valence control ofLaCoO3: Difference between La-deficient and Sr-substituting effects

Electronic state and valence control ofLaCoO3: Difference between La-deficient and Sr-substituting effects

Authors :
Makoto Tanimura
Yushi Shichi
Hidekazu Takahashi
Yasuhide Inoue
Rittaporn Itti
Yoshio Akimune
Yasumasa Koyama
Fumio Munakata
Source :
Physical Review B. 56:979-982
Publication Year :
1997
Publisher :
American Physical Society (APS), 1997.

Abstract

The difference between La-deficient and Sr-substituting effects for La in LaCoO${}_{3}$ has been investigated by using x-ray photoelectron spectroscopy (XPS). On the basis of the relationship between the intensity of the ${}^{2}{T}_{2}$ line and the amount of low-spin Co${}^{3+}$ ions in these compounds, it is pointed out that La${}_{0.9}$CoO${}_{3\ensuremath{-}\ensuremath{\delta}}$ is in a highly covalent low-spin state and La${}_{0.8}$Sr${}_{0.2}$CoO${}_{3\ensuremath{-}\ensuremath{\delta}}$ is in a mixed spin state. From the Co $2p$ and valence-band XPS results, it is pointed out that the electronic state of La${}_{0.9}$CoO${}_{3\ensuremath{-}\ensuremath{\delta}}$ is quite different from that of Sr-substituting La${}_{0.8}$Sr${}_{0.2}$CoO${}_{3\ensuremath{-}\ensuremath{\delta}}.$ In order to explain the difference between La-deficiency and Sr-substitution effects in valence controlling of LaCoO${}_{3}$, it is considered that Sr substitution produces the Co $3d$ holes and La deficiency yields the O $2p$ holes.

Details

ISSN :
10953795 and 01631829
Volume :
56
Database :
OpenAIRE
Journal :
Physical Review B
Accession number :
edsair.doi...........03fa5c2b3c477e429dd44b8027670bfd
Full Text :
https://doi.org/10.1103/physrevb.56.979