Structure and magnetic properties of Ca2Fe1−xMnxAlO5+δ

Carvalho, Maria Graça; Ferreira, Liliana P.; Waerenborgh, J.C.; Tsipis, E.V.; Lopes, A. B.; Godinho, M.

doi:10.1016/j.jssc.2008.06.008

Cited by 12 publications

(13 citation statements)

References 22 publications

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“…2,[4][5][6] These materials (and other oxygen deficient perovskite-like materials, e.g., La y Sr 1Ày (Fe, Ga)O 3Àd ) may have applications as ion conductors in fuel cells and as catalysts (e.g., Ca 2 Fe 2 O 5 ), are an important component of Portland cement (e.g., Ca 2 Al x Fe 2Àx O 5 ), and Mn containing brownmillerites have been examined for colossal magnetoresistance (CMR). [10][11][12][13][14][15][16][17][18] The layered brownmillerite structure is shown in Fig. 1 and contains two ordered oxygen vacancies in every second layer, distinguishing it from perovskites.…”

Section: Introductionmentioning

confidence: 99%

Effects of bond character on the electronic structure of brownmillerite-phase oxides, Ca2B′xFe2−xO5 (B′ = Al, Ga): an X-ray absorption and electron energy loss spectroscopic study

et al. 2009

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Section: Introductionmentioning

confidence: 99%

Effects of bond character on the electronic structure of brownmillerite-phase oxides, Ca2B′xFe2−xO5 (B′ = Al, Ga): an X-ray absorption and electron energy loss spectroscopic study

et al. 2009

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“…2b via Diamond software, [41] respectively, based on the structure reported in literature. [37,42,43] As shown in Fig. 2a Structure Database (ICSD) web and prepared via Diamond Software [41,44] based on the structure reported in literature.…”

Section: Resultsmentioning

confidence: 99%

“…2a Structure Database (ICSD) web and prepared via Diamond Software [41,44] based on the structure reported in literature. [37,42,43] The lattice parameters for the as-prepared Ca2(Al1-xGax)MnO5 in Table 1 indicate that with the increasing substitution of Ga amount (0 < x ≤ 1), the b and c lattice parameters increased obviously and the cell volume also slightly increased, which can be attributed to the increased thickness of the (Al,Ga)O4 layer due to the larger ionic radius of Ga 3+ (0.62 Å) than that of Al 3+ (0.535 Å). However, there is some slight decrease in the a lattice parameters with the increasing of Ga amount in the brownmillerite-type Ca2(Al1-xGax)MnO5 (0 < x ≤ 1.0), which can be attributed to the tilting of the oxygen position in the MnO6 octahedron blocks.…”

Section: Resultsmentioning

confidence: 99%

Oxygen storage capacity and thermal stability of brownmillerite-type Ca2(Al1-xGax)MnO5+δ oxides

Huang

Irvine

2019

Journal of Alloys and Compounds

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Understanding the oxygen uptake/release mechanism in oxygen storage materials is of great importance in the design of energy-related materials and their corresponding applications. In this work, the effects of Ga doping amount on the oxygen storage capacity and thermal stability of Ca2(Al1-xGax)MnO5+δ (0 ≤ x ≤ 1) with a brownmillerite-type structure were investigated. Ca2AlMnO5+δ can reversibly store/release a large amount of excess oxygen (~3.0 wt%) at low temperature (between 300 and 600 o C) under oxidative atmospheres. With the increasing Ga doping amount in Ca2(Al1-xGax)MnO5+δ, these materials uptake less oxygen at higher temperature which can be attributed to the difficulty in the oxidation of tetrahedral GaO4 blocks into octahedral GaO6 blocks under 1 atm O2. However, with the increasing of Ga-substitution amount, these Ca2(Al1-xGax)MnO5+δ (0 ≤ x < 1) can start to uptake oxygen at lower temperatures during the cooling process under flowing O2 due to the distorted structure. The results demonstrated that Ca2(Al1-xGax)MnO5+δ (0 ≤x < 1) can reversibly store/release large amounts of oxygen via just controlling the surrounding temperature and/or oxygen partial pressure but without using reductive gases, which would enable them great potentials in many applications.

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“…Previous experimental work suggested that it is possible to synthesize the compound Ca 2 Mn 1−x Fe x AlO 5 in the entire concentration range (0 ≤ x ≤ 1). 15 We examine the formation energy of Ca 2 Mn 1−x Fe x AlO 5 defined as (12) where E Mn 1−x Fe x , E Mn , and E Fe are the total energies of Ca 2 Mn 1−x Fe x AlO 5 , Ca 2 MnAlO 5 , and Ca 2 FeAlO 5 , respectively. Figure 8a shows the calculated formation energies for symmetrically distinct Ca 2 Mn 1−x Fe x AlO 5 configurations.…”

Section: ■ Introductionmentioning

confidence: 99%

Quantum Chemical Design of Doped Ca₂MnAlO_5+δ as Oxygen Storage Media

Ling¹,

Zhang²,

Jia³

2015

ACS Appl. Mater. Interfaces

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Brownmillerite Ca2MnAlO5 has an exceptional capability to robustly adsorb half-molecules of oxygen and form Ca2MnAlO5.5. To utilize this unique property to regulate oxygen-involved reactions, it is crucial to match the oxygen release-intake equilibrium with targeted reaction conditions. Here we perform a comprehensive investigation of the strategy of tuning the oxygen storage property of Ca2MnAlO5 through chemical doping. For undoped Ca2MnAlO5+δ, our first-principles calculation predicts that the equilibrium temperature at a pressure of 1 atm of O2 is 848 K, which is in excellent agreement with experimental results. Furthermore, the doping of alkaline earth ions at the Ca site, trivalent ions at the Al site, and 3d transition metal ions at the Mn site is analyzed. By the doping of 12.5% of Ga, V, and Ti, the equilibrium temperature shifts to high values by approximately 110-270 K, while by the doping of 12.5% of Fe, Sr, and Ba, the equilibrium temperature is lowered by approximately 20-210 K. The doping of these elements is thermodynamically stable, and doping other elements including Mg, Sc, Y, Cr, Co, and Ni generates metastable compounds. The doping of a higher content of Fe, however, lowers the oxygen storage capacity. Finally, on the basis of our calculated data, we prove that the formation energetics of nondilute interacting oxygen vacancy in doped Ca2MnAlO5.5 scale linearly with a simple descriptor, the oxygen p-band position relative to the Fermi level. The higher-oxygen p-band position leads to a lower vacancy formation energy and thus a lower oxygen release temperature. Understanding such a relationship between fundamental quantum chemical properties and macroscopic properties paves the road to the design and optimization of novel functional oxides.

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Structure and magnetic properties of Ca2Fe1−xMnxAlO5+δ

Cited by 12 publications

References 22 publications

Effects of bond character on the electronic structure of brownmillerite-phase oxides, Ca2B′xFe2−xO5 (B′ = Al, Ga): an X-ray absorption and electron energy loss spectroscopic study

Effects of bond character on the electronic structure of brownmillerite-phase oxides, Ca2B′xFe2−xO5 (B′ = Al, Ga): an X-ray absorption and electron energy loss spectroscopic study

Oxygen storage capacity and thermal stability of brownmillerite-type Ca2(Al1-xGax)MnO5+δ oxides

Quantum Chemical Design of Doped Ca₂MnAlO_5+δ as Oxygen Storage Media

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Structure and magnetic properties of Ca2Fe1−xMnxAlO5+δ

Cited by 12 publications

References 22 publications

Effects of bond character on the electronic structure of brownmillerite-phase oxides, Ca2B′xFe2−xO5 (B′ = Al, Ga): an X-ray absorption and electron energy loss spectroscopic study

Effects of bond character on the electronic structure of brownmillerite-phase oxides, Ca2B′xFe2−xO5 (B′ = Al, Ga): an X-ray absorption and electron energy loss spectroscopic study

Oxygen storage capacity and thermal stability of brownmillerite-type Ca2(Al1-xGax)MnO5+δ oxides

Quantum Chemical Design of Doped Ca2MnAlO5+δ as Oxygen Storage Media

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Quantum Chemical Design of Doped Ca₂MnAlO_5+δ as Oxygen Storage Media