Title

Effect of Oxygen Vacancies on the Magnetic Structure of the La₀.₆Sr₀.₄FeO₃₋δ Perovskite: A Neutron Diffraction Study

Abstract

Magnetic interactions in perovskite compounds of the type La 1-xSr xMO 3-δ (M=3d transition such as Mn and Fe) are presumed to arise through a super exchange between 3d electrons of the magnetic ions via oxygen orbitals. The magnetic structure of La 0.6Sr 0.4FeO 3-δ has been studied with neutron diffraction. Oxygen vacancies were created by annealing samples under various gases including N 2, air and mixtures of CO/CO 2. All La 0.6Sr 0.4FeO 3-δ compounds maintain the rhombohedral structure (space group R3̄c). The air- or oxygen-annealed samples have almost no oxygen vacancies while those made in the reducing atmosphere show 7%-11% oxygen vacancies. The rhombohedral distortion decreases in the reduced samples. All the samples exhibit antiferromagnetic ordering at room temperature, although a small ferromagnetic moment may also be present. The samples with little or no oxygen vacancies show a room temperature magnetic moment of ∼1.4μ B at the Fe site while those having >7% oxygen vacancies show a moment of ∼4.0μ B. Magnetization measurements reveal a much higher magnetic ordering temperature in samples with oxygen vacancies© 2002 American Institute of Physics.

Department(s)

Physics

Second Department

Chemistry

Third Department

Materials Science and Engineering

International Standard Serial Number (ISSN)

0021-8979

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2002 American Institute of Physics (AIP), All rights reserved.

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