Electronic state of {sup 57}Fe used as Moessbauer probe in the perovskites LaMO{sub 3} (M=Ni and Cu)

Journal Article · Thu Nov 15 04:00:00 EST 2007 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2007.09.016· OSTI ID:21043750

Presniakov, Igor ^[1]; Demazeau, Gerard ^[2]; Baranov, Alexei ^[1]; Sobolev, Alexei; Gubaidulina, Tatyana; Rusakov, Viyacheslav ^[1]

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1. Lomonosov Moscow State University, 119992 Leninskie Gory, Moscow (Russian Federation)
2. ICMCB, CNRS, University BORDEAUX 1 'Sciences and Technologies', site de l'ENSCPB-87, Avenue du Dr A. Schweitzer, 33608 PESSAC Cedex (France)

For the first time a comparative study of rhombohedral LaNiO{sub 3} and LaCuO{sub 3} oxides, using {sup 57}Fe Moessbauer probe spectroscopy (1% atomic rate), has been carried out. In spite of the fact that both oxides are characterized by similar crystal structure and metallic properties, the behavior of {sup 57}Fe probe atoms in such lattices appears essentially different. In the case of LaNi{sub 0.99}Fe{sub 0.01}O{sub 3}, the observed isomer shift ({delta}) value corresponds to Fe{sup 3+} (3d{sup 5}) cations in high-spin state located in an oxygen octahedral surrounding. In contrast, for the LaCu{sub 0.99}Fe{sub 0.01}O{sub 3}, the obtained {delta} value is comparable to that characterizing the formally tetravalent high-spin Fe{sup 4+}(3d{sup 4}) cations in octahedral coordination within Fe(IV) perovskite-like ferrates. To explain such a difference, an approach based on the qualitative energy diagrams analysis and the calculations within the cluster configuration interaction method have been developed. It was shown that in the case of LaNi{sub 0.99}Fe{sub 0.01}O{sub 3}, electronic state of nickel is dominated by the d{sup 7} configuration corresponding to the formal ionic 'Ni{sup 3+}-O{sup 2-}' state. On the other hand, in the case of LaCu{sub 0.99}Fe{sub 0.01}O{sub 3} a large amount of charge is transferred via Cu-O bonds from the O:2p bands to the Cu:3d orbitals and the ground state is dominated by the d{sup 9}L configuration ('Cu{sup 2+}-O' state). The dominant d{sup 9}L ground state for the (CuO{sub 6}) sublattice induces in the environment of the {sup 57}Fe probe cations a charge transfer Fe{sup 3+}+O{sup -}(L){yields}Fe{sup 4+}+O{sup 2-}, which transforms 'Fe{sup 3+}' into 'Fe{sup 4+}' state. The analysis of the isomer shift value for the formally 'Fe{sup 4+}' ions in perovskite-like oxides clearly proved a drastic influence of the 4s iron orbitals population on the Fe-O bonds character. - Graphical abstract: Moessbauer spectroscopy study of LaCuO{sub 3} doped with the Moessbauer probe {sup 57}Fe.

• OSTI ID: 21043750
• Journal Information: Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Journal Issue: 11 Vol. 180; ISSN 0022-4596; ISSN JSSCBI
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
CATIONS
CONFIGURATION
CONFIGURATION INTERACTION
COPPER IONS
CRYSTAL STRUCTURE
DOPED MATERIALS
FERRATES
GROUND STATES
HIGH SPIN STATES
IRON 57
IRON COMPOUNDS
IRON IONS
ISOMER SHIFT
LANTHANUM COMPOUNDS
MOESSBAUER EFFECT
NICKEL COMPOUNDS
NICKEL IONS
OXIDES
OXYGEN IONS
PEROVSKITE
SPECTROSCOPY