Structure and Mössbauer Studies of F-O Ordering in Antiferromagnetic Perovskite PbFeO2F
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- 作者：Yoshiyuki Inaguma ; Jean-Marc Greneche ; Marie-Pierre Crosnier-Lopez ; Tetsuhiro Katsumata ; Yvon Calage ; and Jean-Louis Fourquet
- 刊名：Chemistry of Materials
- 出版年：2005
- 出版时间：March 22, 2005
- 年：2005
- 卷：17
- 期：6
- 页码：1386 - 1390
- 全文大小：153K
- 年卷期：v.17,no.6(March 22, 2005)
- ISSN：1520-5002
文摘
The synthesis of PbFeO2F is achieved using a solid-state reaction under high pressure. This perovskitecrystallizes in SG Pm
m (No. 221) with a = 0.39991 (1) nm. The Rietveld refinement using powderX-ray diffraction data shows that the mean structure of this compound can be characterized as follows:(1) the Pb ion statically shifts from the 1a Wyckoff position in the twelve <110> direction toward anions(O, F), and (2) the Fe ion is located in a single crystallographic site. In contrast, hyperfine data estimatedfrom Mössbauer spectra at different temperatures suggest the existence of different Fe sites, and theisomer shift is consistent with the presence of high-spin (HS) Fe3+ ions located in FeO4F2 octahedralunits, where anions are randomly distributed. Such a distribution thus favors two prevailing Fe sites,namely cis and trans. No evidence of O/F ordering in PbFeO2F was detected by electron diffractionexperiments. Finally, in-field Mössbauer spectra unambiguously reveal that PbFe2OF behaves as anantiferromagnet, which is consistent with static magnetic measurements.
m (No. 221) with a = 0.39991 (1) nm. The Rietveld refinement using powderX-ray diffraction data shows that the mean structure of this compound can be characterized as follows:(1) the Pb ion statically shifts from the 1a Wyckoff position in the twelve <110> direction toward anions(O, F), and (2) the Fe ion is located in a single crystallographic site. In contrast, hyperfine data estimatedfrom Mössbauer spectra at different temperatures suggest the existence of different Fe sites, and theisomer shift is consistent with the presence of high-spin (HS) Fe3+ ions located in FeO4F2 octahedralunits, where anions are randomly distributed. Such a distribution thus favors two prevailing Fe sites,namely cis and trans. No evidence of O/F ordering in PbFeO2F was detected by electron diffractionexperiments. Finally, in-field Mössbauer spectra unambiguously reveal that PbFe2OF behaves as anantiferromagnet, which is consistent with static magnetic measurements.