CaMn0.5Ir0.5O2.5: An Anion-Deficient Perovskite Oxide Containing Ir3+

Page, Jacob E; Hayward, Michael A.

doi:10.1021/acs.inorgchem.9b01219

Cited by 7 publications

(5 citation statements)

References 33 publications

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“…Later, Kobayashi et al [32] successfully conducted the reduction of SrFeO3 to SrFeO2 with physically separated CaH2, and it was concluded that the reaction was proceeded via the release of H2 by CaH2. Recently, Page et al [33] reduced CaMn0.5Ir0.5O3 using NaH and a gas mediated reaction process was proposed. Here, our results, which are identical for the physically separated and mixed experiments, once again confirms that the reduction using CaH2 works via H2 gas instead of solid state reaction.…”

Section: Synthesis Of Nd1-xsrxnio2 By Reducing Nd1-xsrxnio3mentioning

confidence: 99%

Synthesis and characterization of bulk Nd1−xSrxNiO2 and Nd
Wang
¹
,
Zheng
²
,
E.
³

et al. 2020
Phys. Rev. Materials
123
6
72
0
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The recent reports of superconductivity in Nd1-xSrxNiO2/SrTiO3 heterostructures have reinvigorated interest in potential superconductivity of low-valence nickelates. Synthesis of Ni 1+ -containing compounds is notoriously difficult. In the current work, a combined sol-gel combustion and high-pressure annealing technique was employed to prepare polycrystalline perovskite Nd1-xSrxNiO3 (x = 0, 0.1 and 0.2). Metal nitrates and metal acetates were used as starting materials, and the latter were found to be superior to the former in terms of safety and reactivity. The Nd1-xSrxNiO3 compounds were subsequently reduced to Nd1-xSrxNiO2 using calcium hydride in a sealed, evacuated quartz tube. To understand the synthesis pathway, the evolution from NdNiO3 to NdNiO2 was monitored using in-situ synchrotron X-ray diffraction during the reduction process. Electrical transport properties were consistent with an insulatormetal transition occurring between x = 0 and 0.1 for Nd1-xSrxNiO3. Superconductivity was not observed in our bulk samples of Nd1-xSrxNiO2. Neutron diffraction experiments at 3 K and 300 K were performed on Nd0.9Sr0.1NiO2, in which no magnetic Bragg reflections were observed, and the results of structural Rietveld refinement are provided. Synthesis of Nd1-xSrxNiO3Nitrate method: Nd1-xSrxNiO3 (x = 0, 0.1 and 0.2) was synthesized via the citrate-nitrate autocombustion synthesis as described by Deganello et al. [23] Metal nitrates Nd(NO3)3•6H2O (Strem Chemicals, 99.999%), Ni(NO3)2 •6H2O (Sigma-Aldrich, 99.999%) and Sr(NO3)3 (Alfa Aesar, 99.97%) were used as starting materials. The metal nitrates were dissolved in a minimum amount of distilled water to obtain a clear solution. The exact concentrations of metal nitrates were determined by inductively coupled plasma mass spectrometry (ICP-MS) to account for variable levels of hydration in the starting materials. Stoichiometric amounts of nitrates were mixed in a beaker to get the desired Nd1-xSrxNiO3 (x = 0 to 0.2) precursor solutions. An aqueous solution of citric acid was then mixed with the precursor solutions at a molar ratio, citric acid to metal ions, of 1.2:1 at room temperature. The pH of the precursor solution was adjusted to ~ 7 by adding 30 wt. % aqueous NH3. The solution was slowly evaporated at 70 °C with continuous mechanical stirring, until a hardened gel was obtained. To carry out the gel decomposition under controlled conditions, the hardened gel was transferred to an alumina crucible, which was then put on a hot plate at 250 -300 °C. The gel first turned to black, and then ignited and underwent a vigorous self-sustaining combustion, yielding an ash product. The combusted powders were then fired at 800 °C for 12 h in an oxygen atmosphere at ambient pressure with a flow rate of 0.2 L/min. The resulting black powder was then ground and pressed into pellets with dimensions of 13 mm diameter and about 0.2 mm thickness. The pellets were subsequently fired at 1000 °C under 150-160 bar of oxygen pressure for 12 hours in a highpressure annealing furnace (Model...

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Section: Synthesis Of Nd1-xsrxnio2 By Reducing Nd1-xsrxnio3mentioning

confidence: 99%

Synthesis and characterization of bulk Nd1−xSrxNiO2 and Nd
Wang
¹
,
Zheng
²
,
E.
³

et al. 2020
Phys. Rev. Materials
123
6
72
0
View full text Add to dashboard Cite

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“…5 A and B ). However, one of the diagnostic features of a typical spin-glass system (low-temperature field-dependent magnetization data displaced from the origin) ( 30 ) is absent in our M vs. H plots ( Fig. 5 C and D ), which could be due to the nearly-fully-ordered character of our sample and the relatively low sensitivity of our M vs. H measurements.…”

Section: Resultsmentioning

confidence: 79%

Electron doping of a double-perovskite flat-band system

Jin

Varnava

et al. 2023

Proc. Natl. Acad. Sci. U.S.A.

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Electronic structure calculations indicate that the Sr 2 FeSbO 6 double perovskite has a flat-band set just above the Fermi level that includes contributions from ordinary subbands with weak kinetic electron hopping plus a flat subband that can be attributed to the lattice geometry and orbital interference. To place the Fermi energy in that flat band, electron-doped samples with formulas Sr 2- x La x FeSbO 6 (0 ≤ x ≤ 0.3) were synthesized, and their magnetism and ambient temperature crystal structures were determined by high-resolution synchrotron X-ray powder diffraction. All materials appear to display an antiferromagnetic-like maximum in the magnetic susceptibility, but the dominant spin coupling evolves from antiferromagnetic to ferromagnetic on electron doping. Which of the three subbands or combinations is responsible for the behavior has not been determined.

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“…This observation is consistent with a large proportion of Ir 3+ (d 6 ) with filled t 2g manifold (J eff = 3/2 and ½), corresponding to a J = 0 ground state. 64,65 .…”

Section: Resultsmentioning

confidence: 99%

Evolution of Oxygen Ligands upon Large Redox Swings of Li₃IrO₄

Perez

Taudul

et al. 2021

J. Electrochem. Soc.

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The limits of intercalation electrochemistry continue to be tested in the quest for ever increasing gains in the storage capability of Li-ion cathodes. The subsequent push for multi-electron reactivity has led to the recognition of the extremely versatile role of oxide ligands in charge compensation when there is a large redox swing. Li 3 IrO 4 is a unique model of such activity because it can reversibly cycle between Li 1 IrO 4 and Li 4.7 IrO 4 . Here, X-ray spectroscopy, magnetic measurements and computational simulations uncover the evolution of O states in the different steps, compared to the involvement of Ir. While the process between Li 1 IrO 4 and Li 3 IrO 4 is dominated by the unconventional lattice oxygen redox, the process between Li 3 IrO 4 and Li 4.7 IrO 4 involves a conventional change of the formal oxidation state of Ir, which affects O due to the high covalency. The O states of Li 3 IrO 4 exhibit a very high reversibility after the whole 3.7-electron process, completely restoring the pristine state.

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CaMn_0.5Ir_0.5O_2.5: An Anion-Deficient Perovskite Oxide Containing Ir³⁺

Cited by 7 publications

References 33 publications

Synthesis and characterization of bulk Nd1−xSrxNiO2 and Nd
Wang
¹
,
Zheng
²
,
E.
³

et al. 2020
Phys. Rev. Materials
123
6
72
0
View full text Add to dashboard Cite

Synthesis and characterization of bulk Nd1−xSrxNiO2 and Nd
Wang
¹
,
Zheng
²
,
E.
³

et al. 2020
Phys. Rev. Materials
123
6
72
0
View full text Add to dashboard Cite

Electron doping of a double-perovskite flat-band system

Evolution of Oxygen Ligands upon Large Redox Swings of Li₃IrO₄

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CaMn0.5Ir0.5O2.5: An Anion-Deficient Perovskite Oxide Containing Ir3+

Cited by 7 publications

References 33 publications

Synthesis and characterization of bulk Nd1−xSrxNiO2 and NdWang1, Zheng2, E.3 et al. 2020Phys. Rev. Materials1236720View full textAdd to dashboardCite

Synthesis and characterization of bulk Nd1−xSrxNiO2 and NdWang1, Zheng2, E.3 et al. 2020Phys. Rev. Materials1236720View full textAdd to dashboardCite

Electron doping of a double-perovskite flat-band system

Evolution of Oxygen Ligands upon Large Redox Swings of Li3IrO4

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Product

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CaMn_0.5Ir_0.5O_2.5: An Anion-Deficient Perovskite Oxide Containing Ir³⁺

Synthesis and characterization of bulk Nd1−xSrxNiO2 and Nd
Wang
¹
,
Zheng
²
,
E.
³

et al. 2020
Phys. Rev. Materials
123
6
72
0
View full text Add to dashboard Cite

Synthesis and characterization of bulk Nd1−xSrxNiO2 and Nd
Wang
¹
,
Zheng
²
,
E.
³

et al. 2020
Phys. Rev. Materials
123
6
72
0
View full text Add to dashboard Cite

Evolution of Oxygen Ligands upon Large Redox Swings of Li₃IrO₄