Synthesis and oxygen content dependent properties of hexagonal DyMnO3+δ

Remsen, S.; Dąbrowski, B.; Chmaissem, O.; Mais, J.; Szewczyk, A.

doi:10.1016/j.jssc.2011.06.037

Cited by 26 publications

(22 citation statements)

References 34 publications

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“…Interestingly, it was shown that the stable hexagonal phase can be converted to the perovskite one by special treatments, e.g., high pressure, 28,29 deposition of strained thin films 30 or by using soft chemistry methods, followed by appropriate annealing. 31 The reverse conversion of the perovskite to the hexagonal structure under reducing conditions was also documented for DyMnO 3 . 7 Until the recent reports by Remsen et al regarding DyMnO 3+d and substituted Dy 1Àx Y x MnO 3+d , 7,31 not much was known about the oxygen hyperstoichiometry in hexagonal manganites.…”

Section: Introductionmentioning

confidence: 82%

“…31 The reverse conversion of the perovskite to the hexagonal structure under reducing conditions was also documented for DyMnO 3 . 7 Until the recent reports by Remsen et al regarding DyMnO 3+d and substituted Dy 1Àx Y x MnO 3+d , 7,31 not much was known about the oxygen hyperstoichiometry in hexagonal manganites. The subsequent paper focused on the structural, magnetic and oxygen storage-related properties of the Dy 1Àx Y x MnO 3+d series, 26 in which the superstructure R3c (tripled along the c-axis, Hex1) of Dy 0.7 Y 0.3 MnO 3.29 was reported.…”

Section: Introductionmentioning

confidence: 82%

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Oxygen storage properties of hexagonal HoMnO_3+δ

Świerczek

Klimkowicz

Nishihara

et al. 2017

Phys. Chem. Chem. Phys.

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Structural and oxygen content changes of hexagonal HoMnO manganite at the stability boundary in the perovskite phase have been studied by X-ray diffraction and thermogravimetry using in situ oxidation and reduction processes at elevated temperatures in oxygen and air. The oxygen storage properties during structural transformation between stoichiometric Hex0 and oxygen-loaded Hex1 phases, transition temperatures and kinetics of the oxygen incorporation and release are reported for materials prepared by the solid-state synthesis and high-impact mechanical milling. Long-term annealing experiments have shown that the Hex0 (δ = 0) → Hex1 (δ ≈ 0.28) phase transition is limited by the surface reaction and nucleation of the new phase for HoMnO 15MM. The temperatures of Hex0 ↔ Hex1 transitions have been established at 290 °C and 250 °C upon heating and cooling, respectively, at a rate of 0.1° min, also indicating that the temperature hysteresis of the transition could possibly be as small as 10 °C in the equilibrium. Ball-milling of HoMnO has only a small effect on improving the speed of the reduction/oxidation processes in oxygen, but importantly, allowed for considerable oxygen incorporation in air at a temperature range of 220-255 °C after prolonged heating. The Mn 2p XAS results of the Mn valence in oxygen loaded samples support the oxygen content determined by the TG method. The magnetic susceptibility data of the effective Mn valence gave inconclusive results due to dominating magnetism of the Ho ions. Comparison of HoMnO with previously studied DyMnO indicates that a tiny increase in the ionic size of lanthanide has a huge effect on the redox properties of hexagonal manganites and that practical properties could be significantly improved by synthesizing the larger average size (Y,Ln)MnO manganites.

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Section: Introductionmentioning

confidence: 82%

Section: Introductionmentioning

confidence: 82%

Oxygen storage properties of hexagonal HoMnO_3+δ

Świerczek

Klimkowicz

Nishihara

et al. 2017

Phys. Chem. Chem. Phys.

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“…But, in pure O2 and in a narrow temperature range, between 250°C and 350°C, or during slow cooling in the same atmosphere, the materials exhibit located exactly on top of each but are shifted by 3/2 1/3 Ch/2 (in the hexagonal setting) 16 30 . After annealing at 190 bar of oxygen pressure, the oxygen content can increase up to δ≈0.40 and at this point the structure transforms into another supercell with Pca21 space group 31 . In this last orthorhombic arrangement, similarly to the aforementioned rhombohedral superstructure, but with lower symmetry, the oxygen excess is located in several partially filled sites within the same hexagonal cavities of the Mn-O layers,…”

Section: Introductionmentioning

confidence: 99%

Pure and Zr-doped YMnO_3+δas a YSZ-compatible SOFC cathode: a combined computational and experimental approach

et al. 2019

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“…Previously we have studied several manganites (A/R)MO 3-d (M = Mn) for which we observed that it is possible to tune the structural transitions between the perovskite phase, which we define as a network of corner-shared MO 6 octahedra, and the non-perovskite phases such as the hexagonal 4H and 2H phases with face-shared MO 6 octahedra for large A = Sr and Ba, respectively, and the layered hexagonal P6 3 cm phase for small R = Dy. [6][7][8] The structural transitions among perovskite and hexagonal phases were relatively easily tunable for manganites by controlling the temperature and oxygen pressure during the synthesis because of the Mn flexible coordination to oxygen and the variable oxidation states of 2+, 3+ and 4+ that affect its ionic size. 9 The stability of the perovskite phase was consistently described in terms of the modified Goldschmidt's tolerance factor 0.855 ≤ t (x,T,d ) ≤ 1, whose definition was extended to the dependence on the temperature (T ) and oxygen content (3-d) that controls the oxidation state of Mn, in addition to the traditional dependence on the chemical composition (x).…”

Section: Introductionmentioning

confidence: 99%

“…8 15 On the other hand the synthesis conditions could also be designed to destabilize the perovskite phase of, for example, DyMnO 3 in favor of the hexagonal P6 3 cm, which exhibits exceptional oxygen absorption/desorption properties at unusually low temperatures. 7,16 The similarity of the observed perovskite and layered hexagonal R3c phases of RMnO 3 to the RMO 3 compounds with the fixed oxidation state M 3+ = In, Ga, Al motivated us to study and compare these systems by focusing on R = Pr.…”

Section: Introductionmentioning

confidence: 99%

High temperature neutron diffraction studies of PrInO₃and the measures of perovskite structure distortion

2015

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The crystal structure of PrInO(3) was investigated in the temperature range 303-1123 K by high-resolution neutron-powder diffraction. The PrInO(3) adopts a highly distorted variant of the perovskite structure with the orthorhombic Pnma space group in the whole temperature range investigated. The bond length and bond-angle analysis revealed a very slow tendency to decrease structural distortion with increasing temperature. Comparison of different parameters quantifying perovskite structure distortion calculated for PrInO(3) and the similar PrAlO(3) and PrGaO(3) shows the advantage of using the tolerance factor t12 calculated for the 12-fold coordinated Pr by geometrical averaging of the individual interatomic distances. An additional advantage of the tolerance factor method results from the possibility of extending it to predict the average structural distortion and the geometrical stability of the perovskites at various temperatures once the accurate dependence of t(x,T,d) on the composition, temperature and oxygen content is found. By comparing PrInO(3) with several AMO(3) perovskites containing ions in the fixed oxidation state on the A and M crystal sites it was found that structural distortion and the tolerance factor t12 for PrInO(3) are consistent with the empirical thermal expansion coefficient based on the bond strength calculation [R. M. Hazen, and C. T. Prewitt, Am. Mineral., 1977, 62(3-4), 309]. In contrast to perovskites AMO(3-d) containing mixed-valent M ions, which allow for a wide range of changes of the tolerance factor t(12)(T,d) as a function of oxygen content, perovskites AMO(3) with M ions in the fixed oxidation state show much less flexibility. This flexibility is further reduced for the A(3+)M(3+)O(3) perovskites like PrInO(3) for which even a large change of the synthesis temperature has a minor effect on controlling the resulting t(12)(T) and the structural phase in comparison with A(2+)M(4+)O3 perovskites. The only parameter left for A(3+)M(3+)O(3) materials allowing formation of various perovskites and hexagonal phases is the total pressure, which may significantly change t(12)(T,P).

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Synthesis and oxygen content dependent properties of hexagonal DyMnO3+δ

Cited by 26 publications

References 34 publications

Oxygen storage properties of hexagonal HoMnO_3+δ

Oxygen storage properties of hexagonal HoMnO_3+δ

Pure and Zr-doped YMnO_3+δas a YSZ-compatible SOFC cathode: a combined computational and experimental approach

High temperature neutron diffraction studies of PrInO₃and the measures of perovskite structure distortion

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Synthesis and oxygen content dependent properties of hexagonal DyMnO3+δ

Cited by 26 publications

References 34 publications

Oxygen storage properties of hexagonal HoMnO3+δ

Oxygen storage properties of hexagonal HoMnO3+δ

Pure and Zr-doped YMnO3+δas a YSZ-compatible SOFC cathode: a combined computational and experimental approach

High temperature neutron diffraction studies of PrInO3and the measures of perovskite structure distortion

Contact Info

Product

Resources

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Oxygen storage properties of hexagonal HoMnO_3+δ

Oxygen storage properties of hexagonal HoMnO_3+δ

Pure and Zr-doped YMnO_3+δas a YSZ-compatible SOFC cathode: a combined computational and experimental approach

High temperature neutron diffraction studies of PrInO₃and the measures of perovskite structure distortion