Electrical conductivity and chemical diffusion coefficient of strontium-doped lanthanum manganites

Journal Article · Wed May 01 04:00:00 EDT 1996 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1006/jssc.1996.0193· OSTI ID:501796

Yasuda, Isamu; Hishinuma, Masakazu ^[1]

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1. Tokyo Gas Co., Ltd. (Japan)

Electrical conductivity and chemical diffusion coefficient of Sr-doped lanthanum manganites, La{sub 1-x}Sr{sub x}MnO{sub 3{+-}{delta}} (x = 0.05 - 0.20), were measured by the dc four-probe technique and relaxation type experiments where a sudden change of oxygen chemical potential was imposed on the pre-equilibrated sample and the change of electrical conductivity was followed as a function of elapsed time. A defect model is proposed to elucidate the oxygen partial pressure dependence of the measured conductivity and the reported oxygen nonstoichiometry. The transient conductivity behavior after an abrupt change of oxygen partial pressure was successfully described by a diffusion model with consideration of partial control by surface reaction. The determined chemical diffusion coefficients, of the order of 10{sup -5} to 10{sup -4} cm{sup 2} s{sup -1} at 1000{degrees}C, increased with decreased oxygen partial pressure due to the thermodynamic enhancement effect. Using the enhancement factor estimated by combination of the proposed defect model and the ambipolar diffusion theory, the oxygen vacancy diffusion coefficients were derived. High vacancy diffusivity comparable to that of Fe- or Co-based perovskites predicts fast oxide ion diffusion under conditions where the manganites show oxygen deficient type nonstoichiometry.

• OSTI ID: 501796
• Journal Information: Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Journal Issue: 2 Vol. 123; ISSN 0022-4596; ISSN JSSCBI
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CRYSTAL DOPING
DIFFUSION
ELECTRIC CONDUCTIVITY
LANTHANUM OXIDES
MANGANESE OXIDES
STOICHIOMETRY
STRONTIUM OXIDES
VACANCIES