This title appears in the Scientific Report :
2015
Please use the identifier:
http://dx.doi.org/10.1016/j.jssc.2015.03.018 in citations.
Crystal structure and high-temperature properties of the Ruddlesden–Popper phases Sr$_{3−x}$Y$_{x}$(Fe $_{1.25}$ Ni$_{0.75}$)O$_{7−δ}$ (0≤x≤0.75)
Crystal structure and high-temperature properties of the Ruddlesden–Popper phases Sr$_{3−x}$Y$_{x}$(Fe $_{1.25}$ Ni$_{0.75}$)O$_{7−δ}$ (0≤x≤0.75)
Ruddlesden–Popper n=2 member phases Sr3−xYxFe1.25Ni0.75O7−δ, 0≤x≤0.75, have been investigated by X-ray and neutron powder diffraction, thermogravimetry and Mössbauer spectroscopy. Both samples as-prepared at 1300 °C under N2(g) flow and samples subsequently air-annealed at 900 °C were studied. The a...
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Personal Name(s): | Samain, Louise |
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Amshoff, Philipp / Biendicho, Jordi J. / Tietz, Frank / Mahmoud, Abdelfattah / Istomin, Sergey Ya. / Grins, Jekabs / Svensson, Gunnar (Corresponding Author) / Hermann, Raphael | |
Contributing Institute: |
Streumethoden; JCNS-2 Werkstoffsynthese und Herstellungsverfahren; IEK-1 JARA-FIT; JARA-FIT Streumethoden; PGI-4 |
Published in: | Journal of solid state chemistry, 227 (2015) S. 45 - 54 |
Imprint: |
Orlando, Fla.
Academic Press
2015
|
DOI: |
10.1016/j.jssc.2015.03.018 |
Document Type: |
Journal Article |
Research Program: |
Jülich Centre for Neutron Research (JCNS) Materials and Processes for Energy and Transport Technologies Controlling Collective States Controlling Collective States |
Publikationsportal JuSER |
Ruddlesden–Popper n=2 member phases Sr3−xYxFe1.25Ni0.75O7−δ, 0≤x≤0.75, have been investigated by X-ray and neutron powder diffraction, thermogravimetry and Mössbauer spectroscopy. Both samples as-prepared at 1300 °C under N2(g) flow and samples subsequently air-annealed at 900 °C were studied. The as-prepared x=0.75 phase is highly oxygen deficient with δ=1, the O1 atom site being vacant, and the Fe3+/Ni2+ ions having a square pyramidal coordination. For as-prepared phases with lower x values, the Mössbauer spectral data are in good agreement with the presence of both 5- and 4-coordinated Fe3+ ions, implying in addition a partial occupancy of the O3 atom sites that form the basal plane of the square pyramid. The air-annealed x=0.75 sample has a δ value of 0.61(1) and the structure has Fe/Ni ions in both square pyramids and octahedra. Mössbauer spectroscopy shows the phase to contain only Fe3+, implying that all Ni is present as Ni3+. Air-annealed phases with lower x values are found to contain both Fe3+ and Fe4+. For both the as-prepared and the air-annealed samples, the Y3+ cations are found to be mainly located in the perovskite block. The high-temperature thermal expansion of as-prepared and air-annealed x=0.75 phases were investigated by high-temperature X-ray diffraction and dilatometry and the linear thermal expansion coefficient determined to be 14.4 ppm K−1. Electrical conductivity measurements showed that the air-annealed samples have higher conductivity than the as-prepared ones. |