Charge Disproportionation and Ordering in La₁/₃Sr₂/₃FeO₃₋δ
The perovskite La1/3Sr2/3FeO3-δ was investigated by neutron diffraction, magnetic and Mössbauer spectroscopy measurements. La1/3Sr2/3FeO3-δ undergoes magnetic ordering at T = 190-200 K accompanied by charge disproportionation. Magnetic peaks due to charge ordering are observed below 200 K. The charge ordering is gradually developed below 200 K along with a charge disproportionation, 2Fe4+ ⇒ Fe3+ + Fe5+. La1/3Sr2/3FeO3-δ shows an antiferromagnetic structure at low temperature. Magnetic moments of about 3 and 1.3 μB were obtained from the neutron diffraction data refinement for Fe3+ and Fe5+ at 15 K, respectively, which suggest that both Fe ions are in a low spin state. These values are significantly lower than those reported by Battle et al for La1/3Sr2/3FeO 2.98. Mössbauer spectra indicate that full charge ordering might be reached below 20 K with no Fe4+.
J. Yang and X. Zhou and Z. Chu and W. M. Hikal and Q. Cai and J. C. Ho and D. C. Kundaliya and W. B. Yelon and W. J. James and H. U. Anderson and H. H. Hamdeh and S. K. Malik, "Charge Disproportionation and Ordering in La₁/₃Sr₂/₃FeO₃₋δ," Journal of Physics Condensed Matter, Institute of Physics - IOP Publishing, Jan 2003.
The definitive version is available at http://dx.doi.org/10.1088/0953-8984/15/29/321
Materials Science and Engineering
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