Synthesis and Oxygen Storage Capacities of Hexagonal Dy1–xYxMnO3+δ

Remsen, S.; Dąbrowski, B.

doi:10.1021/cm2006956

Cited by 83 publications

(83 citation statements)

References 51 publications

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“…14), which coincides with a maximum in electrical conductivity. The deviation in conductivity from the exponential behaviour of a semiconductor stems from the different temperature dependence of the concentration and mobility of holes.…”

Section: Resultsmentioning

confidence: 75%

“…Oxygen vacancies in YMnO 3 have been studied111213, and large oxygen excess has been reported for h- R MnO 3+ δ ( R =Y, Dy) with δ up to 0.35 for R =Dy14. High levels of excess oxygen can cause development of secondary oxidized phases, which are easily detected experimentally15.…”

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confidence: 99%

“…14), making cation vacancy compensation highly unlikely. The layered h- R MnO 3 structure is however ∼11% less dense than the corresponding orthorhombic perovskite structure, suggesting the possibility of interstitial oxygen.…”

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confidence: 99%

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Interstitial oxygen as a source of p-type conductivity in hexagonal manganites

et al. 2016

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Hexagonal manganites, h-RMnO3 (R=Sc, Y, Ho–Lu), have been intensively studied for their multiferroic properties, magnetoelectric coupling, topological defects and electrically conducting domain walls. Although point defects strongly affect the conductivity of transition metal oxides, the defect chemistry of h-RMnO3 has received little attention. We use a combination of experiments and first principles electronic structure calculations to elucidate the effect of interstitial oxygen anions, Oi, on the electrical and structural properties of h-YMnO3. Enthalpy stabilized interstitial oxygen anions are shown to be the main source of p-type electronic conductivity, without reducing the spontaneous ferroelectric polarization. A low energy barrier interstitialcy mechanism is inferred from Density Functional Theory calculations to be the microscopic migration path of Oi. Since the Oi content governs the concentration of charge carrier holes, controlling the thermal and atmospheric history provides a simple and fully reversible way of tuning the electrical properties of h-RMnO3.

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Section: Resultsmentioning

confidence: 75%

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confidence: 99%

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Interstitial oxygen as a source of p-type conductivity in hexagonal manganites

et al. 2016

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“…Early reports showed that the ionic size or the cell volume strongly affects the oxygen release properties. 6,10,11 However, as shown in Figure 9a, for the doping in Ca 2 MnAlO 5+δ no apparent correlation exists for any trend. This is probably because the dopants at different sites behave significantly differently.…”

Section: ■ Discussionmentioning

confidence: 88%

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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“…Due to the oxygen storage and release capacity of YMnO 3 -related system [18], here we use electron beam irradiation to drive the motion of oxygen vacancy under the vacuum environment of a transmission electron microscope (TEM). As a result, the ordered arrangements and high mobility of V O s are identified by selected area electron diffractions (SAED); the corresponding structural models and possible evolution route are proposed.…”

Section: Introductionmentioning

confidence: 99%