Moessbauer spectroscopy analysis of {sup 57}Fe-doped YBaCo{sub 4}O{sub 7+{delta}}: Effects of oxygen intercalation

Journal Article · Sun Mar 15 00:00:00 EDT 2009 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2008.12.001· OSTI ID:21212241

Tsipis, E V ^[1]; Waerenborgh, J C ^[1]; Avdeev, M ^[2]

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1. Chemistry Department, Instituto Tecnologico e Nuclear, CFMC-UL, EN 10, 2686-953 Sacavem (Portugal)
2. Bragg Institute, Australian Nuclear Science and Technology Organization, PMB 1, Menai, NSW 2234 (Australia)

Moessbauer spectroscopy of layered YBaCo{sub 3.96}Fe{sub 0.04}O{sub 7+{delta}} ({delta}=0.02 and 0.80), where 1% cobalt is substituted with {sup 57}Fe isotope, revealed no evidence of charge ordering at 4-293 K. The predominant state of iron cations was found trivalent, irrespective of their coordination and oxygen stoichiometry variations determined by thermogravimetric analysis. The extremely slow kinetics of isothermal oxidation at 598 K in air, and the changes of Fe{sup 3+} fractions in the alternating triangular and Kagome layers in oxidized YBaCo{sub 3.96}Fe{sub 0.04}O{sub 7.80}, may suggest that oxygen intercalation is accompanied with a substantial structural reconstruction stagnated due to sluggish cation diffusion. Decreasing temperature below 75-80 K leads to gradual freezing of the iron magnetic moments in inverse correlation with the content of extra oxygen. The formation of metal-oxygen octahedra and resultant structural distortions extend the temperature range where the paramagnetic and frozen states co-exist, down to 45-50 K. - Graphical abstract: Moessbauer spectroscopy of layered YBaCo{sub 3.96}Fe{sub 0.04}O{sub 7+{delta}} ({delta}=0.02 and 0.80), with 1% {sup 57}Fe isotope substituted for cobalt, revealed no evidence of charge ordering at 4-293 K. The predominant state of iron cations was found trivalent, irrespective of their coordination and oxygen stoichiometry variations determined by thermogravimetric analysis. Decreasing temperature below 75-80 K leads to gradual freezing of the iron magnetic moments in inverse correlation with the content of extra oxygen extending the temperature range where the paramagnetic and frozen states co-exist down to 45-50 K.

• OSTI ID: 21212241
• Journal Information: Journal of Solid State Chemistry, Vol. 182, Issue 3; Other Information: DOI: 10.1016/j.jssc.2008.12.001; PII: S0022-4596(08)00628-2; Copyright (c) 2008 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
BARIUM COMPOUNDS
COBALT COMPOUNDS
DOPED MATERIALS
FREEZING
IRON 57
IRON COMPOUNDS
KINETICS
MAGNETIC MOMENTS
MOESSBAUER EFFECT
OXIDATION
OXIDES
PARAMAGNETISM
TEMPERATURE RANGE 0000-0013 K
TEMPERATURE RANGE 0013-0065 K
TEMPERATURE RANGE 0065-0273 K
TEMPERATURE RANGE 0273-0400 K
TEMPERATURE RANGE 0400-1000 K
THERMAL GRAVIMETRIC ANALYSIS
YTTRIUM COMPOUNDS