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Title: Synthesis, crystal structure and properties of SmBaCo{sub 2−x}Fe{sub x}O{sub 5+δ}

The solid solution formation range in the SmBaCo{sub 2−x}Fe{sub x}O{sub 5+δ} (0≤x≤2) system examined at 1100 °C in air corresponds to 0≤x≤1.1. The crystal structure of SmBaCo{sub 2−x}Fe{sub x}O{sub 5+δ} with x≤0.5 was described as orthorhombic (space group Pmmm), and with 0.6≤x≤1.1—as tetragonal (P4/mmm). The introduction of iron into the cobalt sublattice leads to a gradual increase of the unit cell parameters and volume, accompanied with increasing oxygen content determined by thermogravimetry. The dilatometric curves collected at 25–1100 °C in air exhibit moderate nonlinearities associated with the orthorhombic→tetragonal phase transition, as confirmed by the high-temperature X-ray diffraction analysis. Temperature dependencies of the electrical conductivity measured by 4-probe dc method in the temperature range 25–1000 °C in air display maxima at 300–350 °C, whilst the conductivity decreases with iron additions. These trends were discussed in terms of the defect structure and nature of the main charge carriers in SmBaCo{sub 2−x}Fe{sub x}O{sub 5+δ}. It was also shown that SmBaCo{sub 2−x}Fe{sub x}O{sub 5+δ} is chemically stable with respect to the Ce{sub 0.8}Sm{sub 0.2}O{sub 1.9} solid electrolyte up to 1100 °S, but reacts with Zr{sub 0.85}Y{sub 0.15}O{sub 1.93} even at 900 °S. Highlights: • The solid solution formation range in the SmBaCo{sub 2−x}Fe{sub x}O{submore » 5+δ} system at 1100 °C in air corresponds to 0≤x≤1.1. • The unit cell volume and oxygen content in the solid solutions increase with x. • Oxygen nonstoichiometry of SmBaCo{sub 2−x}Fe{sub x}O{sub 5+δ} solid solutions. • Temperature dependencies of the electrical conductivity exhibit maxima at the temperatures when oxygen exchange with the gaseous phase becomes significant.« less
Authors:
;  [1] ;  [1] ;  [1] ; ;  [2]
  1. Department of Chemistry, Ural Federal University, Yekaterinburg (Russian Federation)
  2. Department of Materials and Ceramic Engineering, CICECO, University of Aveiro (Portugal)
Publication Date:
OSTI Identifier:
22274042
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Solid State Chemistry; Journal Volume: 204; Other Information: Copyright (c) 2013 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; BARIUM; CHARGE CARRIERS; COBALT; ELECTRIC CONDUCTIVITY; IRON; IRON ADDITIONS; ORTHORHOMBIC LATTICES; PEROVSKITE; PHASE TRANSFORMATIONS; SAMARIUM; SOLID ELECTROLYTES; SOLID SOLUTIONS; SPACE GROUPS; SYNTHESIS; TETRAGONAL LATTICES; THERMAL GRAVIMETRIC ANALYSIS; X-RAY DIFFRACTION