Powder X-ray diffraction and Rietveld analysis of La1−xBaxCoO3 (0&lt;x≤0.5)

Luo, Wenjin; Wang, Fangwei

doi:10.1154/1.2358363

Cited by 16 publications

(18 citation statements)

References 11 publications

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“…26 As the Ba content increases, the rhombohedral distortion fades out, and the symmetry of the crystal structure becomes cubic (SG Pm3m) 11 for samples with x = 0.5−0.7. This result is in close agreement with the work of W. Lou et al, 26 who reported the transition from the rombohedral to the cubic symmetry at x ∼ 0.3−0.35. On the other hand, the x = 1.0 sample was refined based on the crystallographic data of the 12H hexagonal phase (SG P 63/mmc) reported by Jacobson and Hutchinson for BaCoO 2.6 .…”

Section: Methodsmentioning

confidence: 99%

Characterization of the La_1−xBa_xCoO_3−δ(0 ≤ x ≤ 1) System as Cathode Material for IT-SOFC

Setevich

Mogni

Caneiro

et al. 2011

J. Electrochem. Soc.

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The influence of temperature and procedure on the phase relationships of La x Ba 1−x CoO 3−δ with 0 ≤ x ≤ 1.0, oxygen nonstoichiometry, thermal and chemical expansion contributions, in air, and the electrochemical response of electrodes formed by three porous layers La x Ba 1−x CoO 3−δ /(50:50wt%)La x Ba 1−x CoO 3−δ +Ce 0.9 Gd 0.1 O 1.95 /Ce 0.9 Gd 0.1 O 1.95 have been investigated. The crystal structures of samples with 0 ≤ x ≤ 0.5 and x = 1.0 were refined satisfactorily with a single phase. The cubic perovskite could be obtained for the x = 0.5−0.7 furnace-cooled samples (∼5 • C/min). This phase was found unstable for x = 0.6 and 0.7, in air, at T ≤ 1000 • C. For x = 0.8 and 0.9 a mixture of phases has been obtained. The expansion coefficient reaches a maximum of 26 × 10 −6 K −1 for x = 0.6 and a minimum of 16 × 10 −6 K −1 for x = 0.8 and 0.9 for T = 20−900 • C. AC impedance spectroscopy measurements were carried out in the temperature range of 400 ≤ T ≤ 700 • C. A minimum polarization resistance Rp ∼ 0.065 -0.075 cm 2 was obtained for 0.4 ≤ x ≤ 0.7 at T = 600 • C, which compares very well with the Rp value reported for composites prepared with cobaltites.Mixed conductor oxides have been systematically investigated in the last years as potential candidates for oxygen separation membranes or cathode material for intermediate temperature solid oxide fuel cells (IT-SOFC). 1-4 In particular, the search for novel materials with high electronic and ionic conductivity along with high catalytic activity to the oxygen reduction reaction in the temperature range of 500 ≤ T ≤ 800 • C is necessary in order to minimize the ohmic loses at the cathode of the IT-SOFC. An additional requirement for the cathode materials is that they need to be chemically and thermally compatible with Ce 0.9 Gd 0.1 O 1.95 (GDC) 5 or La 0.85 Sr 0.15 Mg 0.2 Ga 0.8 O 3−δ (LSGM), 6 which are more suitable electrolytes for IT-SOFC.Recently, several groups have focused their attention on the high temperature properties of the perovskites phases LnBaCo 2 O 5+δ (Ln = La, Nd, Pr, Sm, Gd, Y) 7-11 as potential cathode for IT-SOFC. Both, current-voltage 10, 12 and oxygen permeation 11 measurements, showed that the cubic perovskite phase La 0.5 Ba 0.5 CoO 3−δ (Ln = La) exhibits the highest values of power density and oxygen flux across dense ceramic membranes for the series LnBaCo 2 O 5+δ (Ln = La, Nd, Pr, Sm, Gd, Y). Additionally, a recent study 13 has clearly shown that the oxygen vacancy concentration in the system GdBa 1−x Sr x Co 2 O 5+δ tends to increase with the substitution of Sr 2+ (r i = 1.44 Å) by the alkalineearth cation Ba 2+ (r i = 1.60 Å) with larger ionic radii. 14 This effect was also observed with the incorporation of Ba 2+ in the perovskite phase SrCo 0.8 Fe 0.2 O 3−δ, in order to obtain Ba 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3−δ , which exhibits an excellent performance as cathode material. 15

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Section: Methodsmentioning

confidence: 99%

Characterization of the La_1−xBa_xCoO_3−δ(0 ≤ x ≤ 1) System as Cathode Material for IT-SOFC

Setevich

Mogni

Caneiro

et al. 2011

J. Electrochem. Soc.

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“…Polycrystalline samples of La 1Àx Ba x CoO 3 (LBCO) in the range of 0.0oxo0.18 were fabricated from La 2 O 3 , BaCO 3 and Co 3 O 4 starting materials by the standard solid-state reaction method and X-ray powder diffraction confirmed that the samples were in high purity [25]. dc Magnetization as a function of temperature and external magnetic field was derived using a SQUID magnetometer (Quantum Design MPMS-7).…”

Section: Methodsmentioning

confidence: 99%

Superparamagnetic properties of La1−xBaxCoO3 (0.0<x<0.18)

Luo

Wang

2009

Journal of Magnetism and Magnetic Materials

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“…In this group of materials the metal‐insulator transition was observed, as well as high ionic conductivity . Additionally, the spin configuration of cobalt may vary for this system causing the antiferromagnetic, ferromagnetic and even spin glass behavior . Moreover, high‐temperature electrical properties Ba 0.5 La 0.5 CoO 3 (BLC) have been intensively studied for their potential application as electrode material for intermediate temperature solid oxide fuel cells and electrolyzers (IT‐SOFC/ ‐SOEC) …”

Section: Introductionmentioning

confidence: 99%

“…Lanthanum barium cobaltites crystallize in two crystal structures, that is, disordered cubic (Ba 1− x La x CoO 3− δ ), and ordered tetragonal (BaLaCo 2 O 6 ) . In the cubic phase, La and Ba cations occupy the same perovskite A‐site, while in the tetragonal polymorph, divalent barium and trivalent lanthanum cations form alternating layers of [Co‐O]/[Ba‐O]/[Co‐O]/[La‐O] along the c ‐axis.…”

Section: Introductionmentioning

confidence: 99%

“…In the cubic phase, La and Ba cations occupy the same perovskite A‐site, while in the tetragonal polymorph, divalent barium and trivalent lanthanum cations form alternating layers of [Co‐O]/[Ba‐O]/[Co‐O]/[La‐O] along the c ‐axis. The A‐site cation ordering phenomena is a result of the difference between Ba and La ionic radii and occurs only for x ≥ 0.35 …”

Section: Introductionmentioning

confidence: 99%

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Electric and magnetic properties of lanthanum barium cobaltite

et al. 2019

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The cubic Ba0.5La0.5CoO3‐δ was synthesized using solid state reaction. The structural properties were determined by the simultaneous refinement of Synchrotron Powder X‐ray Diffraction and Neutron Powder Diffraction data. Iodometric titration was used to examine the oxygen stoichiometry and average cobalt oxidation state. Low‐temperature magnetic studies show soft ferromagnetic character of fully oxidized material, with θP = 198(3) K and µeff = 2.11(2) µB. Electric measurements show the thermally activated nature of conductivity at low temperatures, whereas, due to the variable oxidation and spin state of cobalt, a single charge transport mechanism cannot be distinguished. Around room temperature, a wide transition from thermally activated conductivity to semi‐metallic behavior is observed. Under the inert atmosphere, the oxygen content lowers and the cation ordering takes place, leading to coexistence of two, ordered and disordered, phases. As a result of this change, thermally activated conductivity is observed also at high temperatures in inert atmosphere.

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Powder X-ray diffraction and Rietveld analysis of La_1−xBa_xCoO₃ (0<x≤0.5)

Cited by 16 publications

References 11 publications

Characterization of the La_1−xBa_xCoO_3−δ(0 ≤ x ≤ 1) System as Cathode Material for IT-SOFC

Characterization of the La_1−xBa_xCoO_3−δ(0 ≤ x ≤ 1) System as Cathode Material for IT-SOFC

Superparamagnetic properties of La1−xBaxCoO3 (0.0<x<0.18)

Electric and magnetic properties of lanthanum barium cobaltite

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Powder X-ray diffraction and Rietveld analysis of La1−xBaxCoO3 (0<x≤0.5)

Cited by 16 publications

References 11 publications

Characterization of the La1−xBaxCoO3−δ(0 ≤ x ≤ 1) System as Cathode Material for IT-SOFC

Characterization of the La1−xBaxCoO3−δ(0 ≤ x ≤ 1) System as Cathode Material for IT-SOFC

Superparamagnetic properties of La1−xBaxCoO3 (0.0<x<0.18)

Electric and magnetic properties of lanthanum barium cobaltite

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Powder X-ray diffraction and Rietveld analysis of La_1−xBa_xCoO₃ (0<x≤0.5)

Characterization of the La_1−xBa_xCoO_3−δ(0 ≤ x ≤ 1) System as Cathode Material for IT-SOFC

Characterization of the La_1−xBa_xCoO_3−δ(0 ≤ x ≤ 1) System as Cathode Material for IT-SOFC