Structural aspects of the ionic conductivity of La1-xSrxCoO3-δ

R.H.E. van Doorn; A.J. Burggraaf

doi:10.1016/S0167-2738(99)00282-9

Structural aspects of the ionic conductivity of La_1-xSr_xCoO_3-δ

R.H.E. van Doorn^*, A.J. Burggraaf

^*Corresponding author for this work

Inorganic Materials Science

Research output: Contribution to journal › Article › Academic › peer-review

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Abstract

The crystal structure of La_1−xSr_xCoO_3−δ in the composition range 0≤x≤0.8 was investigated by means of powder XRD. A more detailed study was performed on the x=0.7 composition by neutron diffraction, HRTEM, SAED, image analysis and PEELS. The XRD results indicate a long-range cubic perovskite symmetry (spacegroup Pm m) for x>0.5 and a rhombohedrally distorted perovskite structure (spacegroup R c) for x≤0.5. Neutron diffraction of La_0.3Sr_0.7CoO_3−δ, annealed at 650°C in air showed ideal cubic symmetry. HRTEM and SAED studies, however, revealed microdomains with an a_c×a_c×2a_c superstructure in addition to regions without such a superstructure. The superstructure could be explained by assuming the removal of all the oxygen ions from every other (001) AO4/4 plane. PEELS measurements indicated a lower oxidation state for Co in the superstructure regions than in the non-superstructure regions. The importance of oxygen-vacancy ordering on the magnitude of ionic conductivity is discussed.

Original language	English
Pages (from-to)	65-78
Number of pages	14
Journal	Solid state ionics
Volume	128
Issue number	1-4
DOIs	https://doi.org/10.1016/S0167-2738(99)00282-9
Publication status	Published - 2000

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@article{ed682453199d4733b0c7717d5972a86a,

title = "Structural aspects of the ionic conductivity of La1-xSrxCoO3-δ",

abstract = "The crystal structure of La1−xSrxCoO3−δ in the composition range 0≤x≤0.8 was investigated by means of powder XRD. A more detailed study was performed on the x=0.7 composition by neutron diffraction, HRTEM, SAED, image analysis and PEELS. The XRD results indicate a long-range cubic perovskite symmetry (spacegroup Pm m) for x>0.5 and a rhombohedrally distorted perovskite structure (spacegroup R c) for x≤0.5. Neutron diffraction of La0.3Sr0.7CoO3−δ, annealed at 650°C in air showed ideal cubic symmetry. HRTEM and SAED studies, however, revealed microdomains with an ac×ac×2ac superstructure in addition to regions without such a superstructure. The superstructure could be explained by assuming the removal of all the oxygen ions from every other (001) AO4/4 plane. PEELS measurements indicated a lower oxidation state for Co in the superstructure regions than in the non-superstructure regions. The importance of oxygen-vacancy ordering on the magnitude of ionic conductivity is discussed.",

author = "{van Doorn}, R.H.E. and A.J. Burggraaf",

year = "2000",

doi = "10.1016/S0167-2738(99)00282-9",

language = "English",

volume = "128",

pages = "65--78",

journal = "Solid state ionics",

issn = "0167-2738",

publisher = "Elsevier B.V.",

number = "1-4",

}

TY - JOUR

T1 - Structural aspects of the ionic conductivity of La1-xSrxCoO3-δ

AU - van Doorn, R.H.E.

AU - Burggraaf, A.J.

PY - 2000

Y1 - 2000

N2 - The crystal structure of La1−xSrxCoO3−δ in the composition range 0≤x≤0.8 was investigated by means of powder XRD. A more detailed study was performed on the x=0.7 composition by neutron diffraction, HRTEM, SAED, image analysis and PEELS. The XRD results indicate a long-range cubic perovskite symmetry (spacegroup Pm m) for x>0.5 and a rhombohedrally distorted perovskite structure (spacegroup R c) for x≤0.5. Neutron diffraction of La0.3Sr0.7CoO3−δ, annealed at 650°C in air showed ideal cubic symmetry. HRTEM and SAED studies, however, revealed microdomains with an ac×ac×2ac superstructure in addition to regions without such a superstructure. The superstructure could be explained by assuming the removal of all the oxygen ions from every other (001) AO4/4 plane. PEELS measurements indicated a lower oxidation state for Co in the superstructure regions than in the non-superstructure regions. The importance of oxygen-vacancy ordering on the magnitude of ionic conductivity is discussed.

AB - The crystal structure of La1−xSrxCoO3−δ in the composition range 0≤x≤0.8 was investigated by means of powder XRD. A more detailed study was performed on the x=0.7 composition by neutron diffraction, HRTEM, SAED, image analysis and PEELS. The XRD results indicate a long-range cubic perovskite symmetry (spacegroup Pm m) for x>0.5 and a rhombohedrally distorted perovskite structure (spacegroup R c) for x≤0.5. Neutron diffraction of La0.3Sr0.7CoO3−δ, annealed at 650°C in air showed ideal cubic symmetry. HRTEM and SAED studies, however, revealed microdomains with an ac×ac×2ac superstructure in addition to regions without such a superstructure. The superstructure could be explained by assuming the removal of all the oxygen ions from every other (001) AO4/4 plane. PEELS measurements indicated a lower oxidation state for Co in the superstructure regions than in the non-superstructure regions. The importance of oxygen-vacancy ordering on the magnitude of ionic conductivity is discussed.

U2 - 10.1016/S0167-2738(99)00282-9

DO - 10.1016/S0167-2738(99)00282-9

M3 - Article

SN - 0167-2738

VL - 128

SP - 65

EP - 78

JO - Solid state ionics

JF - Solid state ionics

IS - 1-4

ER -

Structural aspects of the ionic conductivity of La1-xSrxCoO3-δ

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Structural aspects of the ionic conductivity of La_1-xSr_xCoO_3-δ