Magnetic phase diagram of Sr<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mrow /><mml:mn>3</mml:mn></mml:msub></mml:math>Fe<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mrow /><mml:mn>2</mml:mn></mml:msub></mml:math>O<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mrow /><mml:mrow><mml:mn>7</mml:mn><mml:mo>−</mml:mo><mml:mi>δ</mml:mi></mml:mrow></mml:msub></mml:math>

Peets, Darren C.; Kim, J.-H.; Dosanjh, P.; Reehuis, M.; Maljuk, A.; Aliouane, N.; Ulrich, C.; Keimer, B.

doi:10.1103/physrevb.87.214410

Cited by 23 publications

(14 citation statements)

References 30 publications

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“…For airannealed samples the changes were smaller, the a-axis being unaffected and the c-axis slightly decreasing with x, resulting in a minor decrease in unit cell volume, as shown in Figure 2, respectively. The variations are similar to what is observed for Y-doped analogues (x ≤ 0.4) except [5][6][7] has been known for a long time and been considered for cathode material in IT-SOFC. The oxygen content of the phase is very dependent on the synthesis conditions, and the (7 − δ) values range is typically between 5.5 and 7 [8].…”

Section: Phase Analysis and Unit Cell Parameterssupporting

confidence: 81%

“…This allows for a tuning of the electronic and electrochemical properties of RP oxides through variations of their oxygen content. Sr3Fe2O7−δ [5][6][7] has been known for a long time and been considered for cathode material in IT-SOFC. The oxygen content of the phase is very dependent on the synthesis conditions, and the (7 − δ) values range is typically between 5.5 and 7 [8].…”

Section: Introductionmentioning

confidence: 99%

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Crystal Structure and Coordination of B-Cations in the Ruddlesden–Popper Phases Sr3−xPrx(Fe1.25Ni0.75)O7−δ (0 ≤ x ≤ 0.4)

et al. 2018

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Compounds Sr3−xPrxFe1.25Ni0.75O7−δ with 0 ≤ x ≤ 0.4 and Ruddlesden–Popper n = 2 type structures were synthesized and investigated by X-ray and neutron powder diffraction, thermogravimetry, and Mössbauer spectroscopy. Both samples, prepared at 1300 °C under N2(g) flow and samples subsequently air-annealed at 900 °C, were studied. The structures contained oxygen vacancies in the perovskite layers, and the Fe/Ni cations had an average coordination number less than six. The oxygen content was considerably higher for air-annealed samples than for samples prepared under N2, 7 − δ = ~6.6 and ~5.6 per formula unit, respectively. Mössbauer data collected at 7 K, below magnetic ordering temperatures, were consistent with X-ray powder diffraction (XRD) and neutron powder diffraction (NPD) results. The electrical conductivity was considerably higher for the air-annealed samples and was for x = 0.1~30 S·cm−1 at 500 °C. The thermal expansion coefficients were measured in air between room temperature and 900 °C and was found to be 20–24 ppm·K−1 overall.

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Section: Phase Analysis and Unit Cell Parameterssupporting

confidence: 81%

Section: Introductionmentioning

confidence: 99%

Crystal Structure and Coordination of B-Cations in the Ruddlesden–Popper Phases Sr3−xPrx(Fe1.25Ni0.75)O7−δ (0 ≤ x ≤ 0.4)

et al. 2018

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“…Phases based on strontium ferrate Sr 3 Fe 2 O 7 À δ [9][10][11] also exhibit RP structures and have been considered for cathode materials. The phases exhibit extended ranges of the oxygen non-stoichiometry, with 7 À δ values ranging from 5.5 to 7 [12].…”

Section: Introductionmentioning

confidence: 99%

Crystal structure and high-temperature properties of the Ruddlesden–Popper phases Sr3−Y (Fe1.25Ni0.75)O7− (0≤x≤0.75)

Samain

Amshoff

Biendicho

et al. 2015

Journal of Solid State Chemistry

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“…A high electronic conductivity may be provided by the perovskite layers and a high oxygen ion mobility by vacancies or interstitials in the rock-salt layers. Phases like Sr 3 Fe 2 O 7Àd have also been studied with respect to their magnetic properties 5 and how they vary with the tuneable parameter of the oxygen content. In a previous study, we investigated RP n ¼ 2 member phases Sr 3Àx Y x Fe 1.25 Ni 0.75 O 7Àd , 0 # x # 0.75.…”

Section: Introductionmentioning

confidence: 99%

A structural study of Ruddlesden–Popper phases Sr_3−xY_x(Fe_1.25Ni_0.75)O_7−δ with x ≤ 0.75 by neutron powder diffraction and EXAFS/XANES spectroscopy

et al. 2018

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IntroductionRuddlesden-Popper (RP) phases are considered as promising candidates for cathode materials in intermediate temperature solid oxide fuel cells (IT-SOFCs) as they can exhibit high mixed oxide-ion and electronic conductivities. 1-4 They have a layered inter-growth structure with alternating layers of perovskite and rock-salt type blocks. A high electronic conductivity may be provided by the perovskite layers and a high oxygen ion mobility by vacancies or interstitials in the rock-salt layers. Phases like Sr 3 Fe 2 O 7Àd have also been studied with respect to their magnetic properties 5 and how they vary with the tuneable parameter of the oxygen content. In a previous study, we investigated RP n ¼ 2 member phases Sr 3Àx Y x Fe 1.25 Ni 0.75 O 7Àd , 0 # x # 0.75. 6 The ideal stoichiometry of an n ¼ 2 RP phase is A 3 B 2 O 7 , where A is an alkaline-earth or rare-earth element, B is a transition metal element, and the structure contains two ABO 3 perovskite layers that alternate with single AO rock-salt layers, For real n ¼ 2 RP phases, the O1 site may be partially or totally vacant and the O3 site may also be partially vacant, while no evidence for O2 vacancies has been found. [8][9][10][11][12][13] The O content per formula unit, 7 À d, may be as low as 5.45.9 For oxygen-decient phases the probable B atom coordination polyhedra are, in varying proportions, octahedra, square pyramids, trigonal bipyramids and tetrahedra, Fig. 2.10 Further types of coordination polyhedra are certainly theoretically possible but we hold them less likely to be present in signicant proportions. For instance, two O3 missing would correspond to a IV-coordination similar to that found for Fe atoms in brownmillerite, although very distorted. The results from XANES suggest, however, that the Fe atoms are predominantly V-coordinated for all x-values.In this study, the structures for een different compositions of Sr 3Àx Y View Article OnlineView Journal | View Issue the study is partly to provide a part of the basis for a better understanding of how RP n ¼ 2 phases can be tailored for IT-SOFC applications and partly to characterize the disorder in the structures from a fundamental point of view. Structural information gained from the NPD data has been supplemented by information from Ni and Fe K-edge EXAFS and XANES spectra. Experimental section Sample preparationThe phases Sr 3Àx Y Time-of-ight (TOF) NPD patterns were collected at room temperature for some of the samples with the POLARIS instrument at ISIS, Rutherford Appleton Laboratory, England, and for the rest with the POWGEN instrument at the Oak Ridge National Laboratory, Tennessee, USA. The structural parameters were rened using the Rietveld method and the Topas soware.14 The space group I4/mmm was used in all renements.Cation compositions were determined by energy dispersive spectroscopy (EDS) micro-analysis with a JEOL 7000F SEM equipped with an Oxford Inca EDS system.Iron and nickel K-edge EXAFS and XANES spectra were measured at the I811 beamline at the MAXlab fac...

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Magnetic phase diagram of Sr3Fe2O7−δ

Cited by 23 publications

References 30 publications

Crystal Structure and Coordination of B-Cations in the Ruddlesden–Popper Phases Sr3−xPrx(Fe1.25Ni0.75)O7−δ (0 ≤ x ≤ 0.4)

Crystal Structure and Coordination of B-Cations in the Ruddlesden–Popper Phases Sr3−xPrx(Fe1.25Ni0.75)O7−δ (0 ≤ x ≤ 0.4)

Crystal structure and high-temperature properties of the Ruddlesden–Popper phases Sr3−Y (Fe1.25Ni0.75)O7− (0≤x≤0.75)

A structural study of Ruddlesden–Popper phases Sr_3−xY_x(Fe_1.25Ni_0.75)O_7−δ with x ≤ 0.75 by neutron powder diffraction and EXAFS/XANES spectroscopy

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Magnetic phase diagram of Sr3Fe2O7−δ

Cited by 23 publications

References 30 publications

Crystal Structure and Coordination of B-Cations in the Ruddlesden–Popper Phases Sr3−xPrx(Fe1.25Ni0.75)O7−δ (0 ≤ x ≤ 0.4)

Crystal Structure and Coordination of B-Cations in the Ruddlesden–Popper Phases Sr3−xPrx(Fe1.25Ni0.75)O7−δ (0 ≤ x ≤ 0.4)

Crystal structure and high-temperature properties of the Ruddlesden–Popper phases Sr3−Y (Fe1.25Ni0.75)O7− (0≤x≤0.75)

A structural study of Ruddlesden–Popper phases Sr3−xYx(Fe1.25Ni0.75)O7−δ with x ≤ 0.75 by neutron powder diffraction and EXAFS/XANES spectroscopy

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A structural study of Ruddlesden–Popper phases Sr_3−xY_x(Fe_1.25Ni_0.75)O_7−δ with x ≤ 0.75 by neutron powder diffraction and EXAFS/XANES spectroscopy