A five-dimensional structural investigation of the misfit layer compound [Bi0.87SrO2]2[CoO2]1.82

Leligny, H.; Grebille, D.; Pérez, Olivier; Masset, A. C.; Hervieu, M.; Raveau, B.

doi:10.1107/s0108768199012586

Cited by 154 publications

(127 citation statements)

References 26 publications

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“…As a consequence, some other layered were found to exhibit good thermoelectric properties [3][4][5]. Moreover, they can operate at high temperature in air without degradation, as compared to the intermetallic thermoelectric compounds, increasing ZT values.…”

Section: Introductionmentioning

confidence: 99%

Mejora de las propiedades termoeléctricas de Bi2Sr2Co1.8Ox por métodos de síntesis en disolución

Torres¹,

Sotelo²,

Rasekh³

et al. 2012

Bol. Soc. Esp. Ceram. Vidr.

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Several solution synthetic methods, sol-gel and a polymeric route, have been studied in order to obtain Bi 2 Sr 2 Co 1.8 O x ceramics with improved thermoelectric properties, compared to the classical solid state reaction. The products obtained by these different methods have been compared using DTA-TGA, powder X-ray diffraction, scanning electron microscopy, and thermoelectric characterizations. All the samples obtained by solution synthesis show higher homogeneity and lower content of secondary phases. The main differences in thermoelectrical properties are due to the decrease of electrical resistivity in samples obtained by solution methods, compared with the solid state obtained samples. Between them, the decrease is especially high for those samples prepared by the polymer solution method. Therefore, the polymeric solution synthesis route is shown to yield a power factor four times higher than the obtained for the solid state and sol-gel methods at room temperature.Keywords: Processing, Electrical properties, Microstructure, Thermopower, Cobaltites. Mejora de las propiedades termoeléctricas de Bi 2 Sr 2 Co 1.8 O x por métodos de síntesis en disoluciónSe han obtenido cerámicas termoeléctricas Bi 2 Sr 2 Co 1.8 O x utilizando varios métodos de síntesis, el clásico por estado sólido, sol-gel y de matriz polimérica. Se han comparado los productos obtenidos por las diferentes vías a través de técnicas de DTA-TGA, difracción de rayos X en polvo, microscopía electrónica de barrido y de caracterización termoeléctrica. Todas las muestras obtenidas por los métodos en disolución poseen una mayor homogeneidad y menor contenido de fases secundarias. La principal diferencia en las propiedades termoeléctricas es debida a la disminución de la resistividad eléctrica en las muestras obtenidas por medio de métodos en disolución, comparado con las que se obtienen por estado sólido. Entre ellas, la reducción de la resistividad es mucho mayor para las que se obtienen por el método de matriz polimérica. Además, los materiales obtenidos por este último método poseen un factor de potencia, a temperatura ambiente, cuatro veces mayor que el obtenido en las sintetizadas por los otros dos métodos estudiados.

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Section: Introductionmentioning

confidence: 99%

Mejora de las propiedades termoeléctricas de Bi2Sr2Co1.8Ox por métodos de síntesis en disolución

Torres¹,

Sotelo²,

Rasekh³

et al. 2012

Bol. Soc. Esp. Ceram. Vidr.

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“…Since the discovery of large thermoelectricity in Na x CoO 2 [1], enthusiastic efforts have been devoted to explore new Co oxides exhibiting high thermoelectric performances, and some layered cobaltites, such as [Ca 2 1.82 were found to exhibit good thermoelectric (TE) properties as well [2][3][4].…”

Section: Introductionmentioning

confidence: 99%

Neutron diffraction texture analysis and thermoelectric properties of BiCaCoO misfit compounds

Guilmeau¹,

Pollet²,

Grebille³

et al. 2008

Materials Research Bulletin

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Sintered, textured and single crystal products of the layered misfit [Bi 0.81 CaO 2 ] 2 [CoO 2 ] 1.69 cobaltite have been successfully synthesized and characterized. Based on structure and texture models, the orientation distribution of the hot-forged sample was successfully analysed by neutron diffraction. The results gave a clear description of the fiber texture with c-axes of the plate-like grains aligned parallel to the hot-forging direction. In terms of transport properties, the decrease of the electrical resistivity according to the degree of alignment and crystallinity of the materials evidenced the important role of the texturation and the strong anisotropy existing in these misfit layered cobaltites.

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“…Une analyse systématique de différentes structures de ce type a également montré la similarité des couches CoO 2 du deuxième sous-système, qui tend à montrer la rigidité ainsi que la stabilité spécifique de ce type de couches, qui est responsable des propriétés thermoélectriques de ces structures. Certaines structures révèlent un degré de complexité supplémentaire en associant une modulation commensurable ou incommensurable, indépendante du caractère composite, et nécessitant pour la résolution structurale un formalisme à 5 dimensions [18].…”

Section: La Structure Compositeunclassified

Ordres complexes et apériodicités

Grebille

2008

Études Structurales Par Diffraction Des Neutrons

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Abstract. Some basic theoretical considerations showed that the classical description of the crystalline state through a three dimensional periodicity is not sufficient to take into account all the possible long range order atomic structures. This long range order can be associated to a supercrystal described in a superspace of dimension n > 3. The real aperiodic structure and its experimental diffraction pattern can be recovered through a section-projection method in the superspace. Some actual examples of this aperiodic order are the quasicrystals, the modulated structures and the misfit compounds. Their specificities are described here et some structural examples are given to illustrate the previous theoretical considerations.Résumé. Quelques considérations théoriques simples ont montré que la description de l'ordre cristallin par une triple périodicité n'est pas suffisante pour rendre compte de la notion d'ordre à grande distance. Celle-ci peut être retrouvée à travers une méthode de section-projection d'un supercristal dans un espace de dimension n > 3. Des réalisations concrètes de cet ordre apériodique sont les quasicristaux, les structures modulées et les structures composites. Leurs particularités sont décrites ici et quelques exemples de structures illustrent les considérations théoriques précédentes.

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A five-dimensional structural investigation of the misfit layer compound [Bi_0.87SrO₂]₂[CoO₂]_1.82

Cited by 154 publications

References 26 publications

Mejora de las propiedades termoeléctricas de Bi<sub>2</sub>Sr<sub>2</sub>Co<sub>1.8</sub>O<sub>x</sub> por métodos de síntesis en disolución

Mejora de las propiedades termoeléctricas de Bi<sub>2</sub>Sr<sub>2</sub>Co<sub>1.8</sub>O<sub>x</sub> por métodos de síntesis en disolución

Neutron diffraction texture analysis and thermoelectric properties of BiCaCoO misfit compounds

Ordres complexes et apériodicités

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