Structural, magnetic and electronic properties of LaNi{sub 0.5}Fe{sub 0.5}O{sub 3} in the temperature range 5-1000 K.

Journal Article · Tue Apr 01 04:00:00 EDT 2008 · J. Sol. St. Chem.

DOI:https://doi.org/10.1016/j.jssc.2008.03.041· OSTI ID:1008289

Gateshki, M; Suescun, L; Kolesnik, S; Mais, J; Swierczek, K; Short, S; Dabrowski, B ^[1]

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1. Materials Science Division

The structure, magnetism, transport and thermal expansion of the perovskite oxide LaNi{sub 0.5}Fe{sub 0.5}O{sub 3} were studied over a wide range of temperatures. Neutron time-of-flight data have shown that this compound undergoes a first-order phase transition between 275 and 310 K. The structure transforms from orthorhombic (Pbnm) at low temperatures to rhombohedral (R3{sup -}c) above room temperature. This phase transition is the cause for the previously observed co-existence of phases at room temperature. The main structural modification associated with the phase transition is the change of tilting pattern of the octahedra from a{sup +}b{sup -}b{sup -} at low temperatures to a{sup -}a{sup -}a{sup -} at higher. Magnetic data strongly suggests that a spin-glass magnetic state exists in the sample below 83 K consistent with the absence of magnetic ordering peaks in the neutron data collected at 30 K. At high temperatures the sample behaves as a small polaron electronic conductor with two regions of slightly different activation energies of 0.07 and 0.05 eV above and below 553 K, respectively. The dilatometric data show an average thermal expansion coefficient of 14.7 x 10{sup -6} K{sup -1} which makes this material compatible with frequently used electrolytes in solid oxide fuel cells.

• Research Organization: Argonne National Laboratory (ANL)
• Sponsoring Organization: SC; NSF
• DOE Contract Number: AC02-06CH11357
• OSTI ID: 1008289
• Report Number(s): ANL/MSD/JA-68954
• Journal Information: J. Sol. St. Chem., Journal Name: J. Sol. St. Chem. Journal Issue: Apr. 2008 Vol. 181; ISSN 0022-4596
• Country of Publication: United States
• Language: ENGLISH

Related Subjects

30 DIRECT ENERGY CONVERSION
ELECTROLYTES
MAGNETISM
MODIFICATIONS
NEUTRONS
OXIDES
PEROVSKITE
POLARONS
SOLID OXIDE FUEL CELLS
THERMAL EXPANSION
TRANSPORT