Dependence of crystal symmetry, electrical conduction property and electronic structure of LnFeO3 (Ln: La, Pr, Nd, Sm) on kinds of Ln3+

Eiki NIWA; Tsubasa SATO; Yuki WATANABE; Yuichiro TOYOTA; Yoshikiyo HATAKEYAMA; Ken JUDAI; Katsumi SHOZUGAWA; Motoyuki MATSUO; Takuya HASHIMOTO

doi:10.2109/jcersj2.123.501

Papers

Dependence of crystal symmetry, electrical conduction property and electronic structure of LnFeO₃ (Ln: La, Pr, Nd, Sm) on kinds of Ln³⁺

Eiki NIWA, Tsubasa SATO, Yuki WATANABE, Yuichiro TOYOTA, Yoshikiyo HATAKEYAMA, Ken JUDAI, Katsumi SHOZUGAWA, Motoyuki MATSUO, Takuya HASHIMOTO

著者情報

Eiki NIWA
Department of Physics, College of Humanities and Sciences, Nihon University
Tsubasa SATO
Department of Physics, College of Humanities and Sciences, Nihon University
Yuki WATANABE
Department of Physics, College of Humanities and Sciences, Nihon University
Yuichiro TOYOTA
Department of Physics, College of Humanities and Sciences, Nihon University
Yoshikiyo HATAKEYAMA
Department of Physics, College of Humanities and Sciences, Nihon University
Ken JUDAI
Department of Physics, College of Humanities and Sciences, Nihon University
Katsumi SHOZUGAWA
Department of Multidisciplinary Sciences, Graduate School of Arts and Sciences, The University of Tokyo
Motoyuki MATSUO
Department of Multidisciplinary Sciences, Graduate School of Arts and Sciences, The University of Tokyo
Takuya HASHIMOTO
Department of Physics, College of Humanities and Sciences, Nihon University

キーワード: Perobskite-type oxide, X-ray diffraction, Electrical conductivity, Mossbauer spectroscopy, Diffuse reflecrance spectroscopy, Crystallite symmetry, Electrical conduction property, Electronic structure

ジャーナルフリー

2015 年 123 巻 1438 号 p. 501-506

DOI https://doi.org/10.2109/jcersj2.123.501

詳細

抄録

Dependence of crystal symmetry, electrical conductivity, chemical state of Fe and optical property of LnFeO₃ (Ln: La, Pr, Nd, Sm) on kinds of Ln³⁺ was investigated. All the LnFeO₃ showed orthorhombic structure, with which order of high crystal symmetry was LaFeO₃ > PrFeO₃ > NdFeO₃ > SmFeO₃. Using tolerance factor, the order was successfully explained. The electrical conductivity of all the specimens could be explained by using small polaron hopping model. With increasing crystallite symmetry, electrical conductivity increased and activation energy for hopping conduction decreased. This can be ascribed to larger overlapping of Fe3d orbital and O2p orbital on nearly linear Fe–O–Fe bond in LnFeO₃ with higher crystal symmetry. The larger overlapping of Fe3d orbital and O2p orbital in LnFeO₃ with higher crystal symmetry can also be an origin of larger spin–spin interaction detected by Mössbauer spectroscopy and larger optical band gap observed by diffuse reflectance spectroscopy. Since chemical state of Fe, evaluated by Mössbauer spectroscopy, in LnFeO₃ is fundamentally constant at +3 regardless of kinds of Ln³⁺, carrier concentration of LnFeO₃ was revealed to be constant. It is concluded that the predominant factor which determine the electrical property of LnFeO₃ is mobility affected by crystal symmetry.

責任著者(Corresponding author)

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