Nanostructured Gd0.8Sr0.2Fe0.8M0.2O3 (M=Cr, Ga) materials for solid oxide fuel cell cathodes

AbstractPolycrystalline samples of Gd0.8Sr0.2Fe0.8M0.2O3 (M=Cr, Ga) are prepared by combustion route and pore wetting technique in order to compare the influence of the morphology in the performance of two cathodes for Solid Oxide Fuel Cells. When polycarbonate membranes are used as templates nanowire arrays with a diameter of 50–70 nm are obtained. Comparing the results obtained by Electrochemical Impedance Spectroscopy (EIS) measurements, it is clearly observed that the cathodic resistance considerably decreases when optimized synthesis parameters are used, obtaining a better performance for the Gd0.8Sr0.2Fe0.8Ga0.2O3 nanowires with an area specific resistance (ASR) value at 850∘C of 0.195 Ω cm2

Magnetic ionic plastic crystal: choline[FeCl4]

A novel organic ionic plastic crystal (OIPC) based on a quaternary ammonium cation and a tetrachloroferrate anion has been synthesized with the intention of combining the properties of the ionic plastic crystal and the magnetism originating from the iron incorporated in the anion. The thermal analysis of the obtained OIPC showed a solid?solid phase transition below room temperature and a high melting point above 220 1C, indicating their plastic crystalline behaviour over a wide temperature range, as well as thermal stability up to approximately 200 1C. The magnetization measurements show the presence of three-dimensional antiferromagnetic ordering below 4 K. The results from electrochemical characterization display a solid-state ionic conduction sufficiently high and stable (between 10 2.7 and 10 3.6 S cm 1 from 20 to 180 1C) for electrochemical applications

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Las Prácticas Tuteladas (Estancias) es una asignatura troncal que debe estar dotada de profesorado, instalaciones y medios suficientes para poderla impartir con la mayor calidad. En la actualidad siguen pendientes estas dotaciones y es urgen resolverlo ya que esta situación no se va a poder mantener por mucho tiempo y es bueno dar solución a los problemas en momentos de sosiego y no con las prisas de cuando no se dispone de tiempo para reflexionarTutelage practices (exchange) is a main subjet that must be endowed with a body of teachers and the necesary facilities as to impart it with the highes quality. Such endowments are still without been given and it is urgent to solve this situations as it can not ben longer maintained and it is better to solve problems in periods of calm when there is time enough as to reflct than in haste

Unusual magnetic properties in Pr1-xSrxFe0.8Ni0.2O3-d; (0.3=< x)

Pr1−xSrxFe0.8Ni0.2O3−delta (x=0.1, 0.2, and 0.3) polycrystalline phases were prepared by combustion synthesis. Their magnetic properties and Mössbauer effect have been examined in the range 5–300 K. Mössbauer spectroscopy shows the existence of charge disproportionation in several of the samples at low temperatures. Meanwhile, the samples present multiple features pointing out a frustrated magnetic order, with competing ferro- and antiferromagnetic interactions. Additionally, exchange bias (EB) phenomena have been observed. Hence, when the samples are cooled in a static magnetic field down to temperatures below 50 K, the hysteresis loops shift in the opposite direction to the applied biasing field, with shifts up to 10 kOe and more, and a small vertical shift of the loops also appears. This behavior seems linked to spin disorder and to the appearance of ferromagnetic (FM) ordered regions at low temperatures when cooling with a high applied field. The growth of these FM regions is likely due to the aligning role of an important cooling magnetic field over Ni-Fe and Fe5+-Fe3+ FM interactions. The higher FM contributions and therefore EB values found in the samples presenting charge disproportionation are related to the formation of FM regions in Fe5+-rich areas

Structural and electrical properties of thin films of Pr0.8Sr0.2Fe0.8Ni0.2O3−δ

Pr0.8Sr0.2Fe0.8Ni0.2O3−δ (PN22) films have been deposited at different temperatures on yttria-stabilized zirconia (YSZ) substrates by pulsed laser deposition (PLD) for application to thin film solid oxide fuel cell cathodes..

Novel composition above the limit of Bi:Zr solid solution; synthesis and physical properties of Bi1.33Zr0.67O3+δ

This paper presents an increase to x = 0.67 of the zirconium content in the conductive Bi2−xZrxO3+δ solid solution. Complete incorporation of Zr in the βIII-Bi2O3 structure, confirmed by X-ray powder diffraction, has produced a phase with a lower volume and superior conductivity than those predicted by an earlier study..