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应用熔盐路线通过控制温度和时间成功合成了微立方和纳米片层形貌的SrFeO3-δ化合物.X射线衍射、场发射扫描电子显微镜、透射电子显微镜和能量色散X射线光谱(EDS)以及热重分析(TGA)结果表明,微立方形貌化合物SrFeO2.86为四方相,空间群I4/mmm,纳米片层形貌化合物SrFeO2.62是钙铁矿(空间群Ibma)和正交相(空间群Cmmm)的复合物.磁学性能研究表明,SrFeO3-δ形貌对其性能有明显地影响;自旋失挫的减少与铁磁相互作用的增加密切关联;尽管成分几乎相同,但是形貌上的各向异性导致了明显不同的磁学性能.

SrFeO3-δ products with microcube-shaped tetragonal type,and nano lamellae-shaped brounmillerite and orthorhombic mixed type were successfully synthesized by a molten salt route through controlling temperature and time and lid-closure reaction.The synthesized products were systematically studied by X-ray powder diffraction,field-emission scanning electron microscopy,transmission electron microscopy,and energy dispersive X-ray spectroscopy as well as thermogravimetric analysis.The results show that the sample SrFeO2.86 has a tetrahedral symmetry with I4/mmm supercell.Evidence of weak superstructures,reflecting local oxygen ordering,is also obtained from electron diffraction.SrFeO2.62 was found to be a composite material by combination of a brownmillerite phase with Ibma space group and an orthorhombic structure with Cmmm space group.The results of magnetic properties indicate that the morphology of the SrFeO3-δ products has great effects on their properties.Reduced spin frustration is associated with an increasing ferromagnetic interaction.The shape anisotropy results in distinct difference of magnetic properties in different oxides with nearly the same composition.

参考文献

[1] Steele B C H.Ceramic Electrochemical Reactors Incorporating Solid Oxide Electrolytes[J].British Ceram Proc,1988,43:163-186.
[2] Steele B C H.Ceramic Ion Conducting Membranes[J].Curr Opin Solid State Mater Sci,1996,1(5):684-691.
[3] Adler P,Lebon A,Damljanovic V,et al.Magnetoresistance Effects in SrFeO3-δ:Dependence on Phase Composition and Relation to Magnetic and Charge Order[J].Phys Rev B,2006,73:094451.
[4] Schmidt M,Hofmann M,Campbell S J.Magnetic Structure of Strontium Ferrite Sr4Fe4 O11[J].J Phys Condens Matter,2003,15:8691-8701.
[5] Srinath S,Mahesh Kumar M,Post M L,et al.Magnetization and Magnetoresistance in Insulating Phases of SrFeO3-δ[J].Phys Rev B,2005,72:054425.
[6] Nakamura S,Iida S.New Data on Electrical Properties and Antiferromagnetism of Highly Oxidized Perovskite SrFeOx(2.5 < x < 3.0)[J].Jpn J Appl Phys,1995,34:L291-L293.
[7] Takeda Y,Kanno K,Takada T,et al.Phase Relation in the Oxygen Nonstoichiometric System,SrFeOx(2.5 ≤ x ≤ 3.0)[J].J Solid State Chem,1986,63(2):237-249.
[8] Hodges J P,Short S,Jorgensen J D,et al.Evolution of Oxygen-Vacancy Ordered Crystal Structures in the Perovskite Series SrnFen O3n-1(n=2,4,8,and ∞),and the Relationship to Electronic and Magnetic Properties[J].J Solid State Chem,2000,151(2):190-209.
[9] Fournes L,Potin Y,Grenier J C,et al.High Temperature M(o)ssbauer Spectroscopy of Some SrFeO3-y Phases[J].Solid State Commun,1987,62(4):239-244.
[10] Greaves C,Jacobson A J,Tofield B C,et al.A Powder Neutron Diffraction Investigation of the Nuclear and Magnetic Structure of Sr2 Fe2O5[J].Acta Crystallogr,1975,B31:641-646.
[11] Berastegui P,Eriksson S G,Hull S.A Neutron Diffraction Study of the Temperature Dependence of Ca2Fe2O5[J].Mater Res Bull,1999,34(2):303-314.
[12] Schmidt M,Campbell S J.Crystal and Magnetic Structures of Sr2 Fe2O5 at Elevated Temperature[J].J Solid State Chem,2001,156(2):292-304.
[13] Harder M,Muller-Buschbaum H.Darstellung und Untersuchung von Sr2Fe2O5-Einkristallen Ein Beitrag zur Kristallchemie yon M2Fe2O5-Verbindungen[J].Z Anorg Allg Chem,1980,464(1):169-175.
[14] Petit C,Taleb A,Pileni M P.Self-Organization of Magnetic Nanosized Cobalt Particles[J].Adv Mater,1998,10(3):259-261.
[15] Li B,Xie Y,Huang J X,et al.Synthesis by a Solvothermal Route and Characterization of CuInSe2 Nanowhiskers and Nanoparticles[J].Adv Mater,1999,11(17):1456-1459.
[16] Chang H,Kosari F,Andreadakis G,et al.DNA-Mediated Fluctuations in Ionic Current through Silicon Oxide Nanopore Channels[J].Nono Lett,2004,4(8):1551-1556.
[17] Wang X,Zhuang J,Peng Q,et al.A General Strategy for Nanocrystal Synthesis[J].Nature,2005,437:121-124.
[18] Tsujimoto Y,Tassel C,Hayashi N,et al.Infinite-layer Iron Oxide with a Square-planar Coordination[J].Nature,2007,450:1062-1065.
[19] Cheary R W,Coelho A A.Programs XFIT and FOURYA[M].England,Warrington:Daresbury Laboratory,1996.
[20] Bail A Le,Duroy H,Fourquet J L.Ab-initio Structure Determination of LiSbWO6 by X-ray Powder Diffraction[J].Mater Res Bull,1988,23(3):447-452.
[21] Larson A C,Dreele R B Von.General Structure Analysis System(GSAS)[M].Los Alamos National Laboratory,Report LAUR 86-748,Los Alamos,2000.
[22] Eriksson A,Lindberg F,Sensson G,et al.Influence of Iron Addition on the Oxygen-deficient Sr0.85 Bi0.15 Co1-xFex O3-δ(0 ≤x≤1.0) Perovskites[J].J Solid State Chem,2008,181(8):2031-2040.
[23] Lebedev O I,Verbeeck J,Tendeloo G.Structure and Microstructure of Epitaxial SrnFenO3n-1 Films[J].Philos Mag,2004,84(36):3825-3841.
[24] Vidya R,Ravindran P,Fjellvag H,et al.Spin-and Charge-ordering in Oxygen-vacancy-ordered Mixed-valence Sr4 Fe4O11[J].Phys Rev B,2006,74:054422.
[25] Zhao Y M,Mahendiran R,Nguyen N,et al.SrFeO2.95:A Helical Antiferromagnet with Large Magnetoresistance[J].Phys Rav B,2001,64:024414.
[26] Lebon A,Adler P,Bernhard C,et al.Magnetism,Charge Order,and Giant Magnetoresistance in SrFeO3-δ Single Crystals[J].Phys Rev Lett,2004,92:037202.
[27] Goodenough J B.Theory of the Role of Covalence in the Perovskite-Type Manganites[La,M(Ⅱ)]MnO3[J].Phys Rev,1955,100:564-573.
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