Spinel, YbFe2O4, and Yb2Fe3O7 types of structures for compounds in the In2O3 and Sc2O3A2O3BO systems [A: Fe, Ga, or Al; B: Mg, Mn, Fe, Ni, Cu, or Zn] at temperatures over 1000°C

Kimizuka, Noboru; Mohri, Takahiko

doi:10.1016/0022-4596(85)90290-7

Cited by 220 publications

(171 citation statements)

References 5 publications

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“…Herein, we introduce a Cu 2+ (S = 1/2) based potential QSL system Sc 2 Ga 2 CuO 7 (SGCO). This system was first reported by Kimizuka et al [22] and the structure type was identified as similar to Yb 2 Fe 3 O 7 [23]. However, no other data have been reported up to now.…”

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confidence: 81%

Sc2Ga2CuO7: A possible quantum spin liquid near the percolation threshold

et al. 2015

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Sc 2 Ga 2 CuO 7 (SGCO) crystallizes in a hexagonal structure (space group: P 6 3 /mmc), which can be seen as an alternating stacking of single and double triangular layers. Combining neutron, x-ray, and resonant x-ray diffraction, we establish that the single triangular layers are mainly populated by nonmagnetic Ga 3+ ions (85% Ga and 15% Cu), while the bilayers have comparable population of Cu 2+ and Ga 3+ ions (43% Cu and 57% Ga). Our susceptibility measurements in the temperature range 1.8-400 K give no indication of any spin-freezing or magnetic long-range order (LRO). We infer an effective paramagnetic moment μ eff = 1.79 ± 0.09 μ B and a Curie-Weiss temperature θ CW of about −44 K, suggesting antiferromagnetic interactions between the Cu 2+ (S = 1/2) ions. Low-temperature neutron powder diffraction data showed no evidence for LRO down to 1.5 K. In our specific heat data as well, no anomalies were found down to 0.35 K, in the field range 0-140 kOe. The magnetic specific heat C m , exhibits a broad maximum at around 2.5 K followed by a nearly power law C m ∝ T α behavior at lower temperatures, with α increasing from 0.3 to 1.9 as a function of field for fields up to 90 kOe and then remaining at 1.9 for fields up to 140 kOe. Our results point to a disordered ground state in SGCO.

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confidence: 81%

Sc2Ga2CuO7: A possible quantum spin liquid near the percolation threshold

et al. 2015

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“…The investigated multicomponent oxides have rhombohedral R3m layered crystal structure of YbFe 2 O 4 type and belong to the homologous series RAO 3 (MO) m with m=1 [18,19,28]. In these compounds, R 3+ ions (In or Sc) have octahedral coordination with the oxygen atoms and reside in 3(a) position (Yb), whereas both A 3+ (Al or Ga) and M 2+ (Ca, Mg, Zn or Cd) ions reside in 6(c) position (Fe) and are distributed randomly [29].…”

Section: Crystal Structurementioning

confidence: 99%

“…Since the exact internal positions of atoms are not known, we used those of the YbFe 2 O 4 [18] as the starting values, and then optimized the internal positions of all atoms in the supercell via minimization of the total energy and the atomic forces. During the optimization the lattice parameters were fixed at the experimental values [18,19,23,28] except for InAlCaO 4 , InGaCaO 4 , and InGaCdO 4 where a and c were optimized since the experimental values are unavailable. Our optimized structural parameters for the latter compounds as well as the optimized z values for every structure under consideration are given in Table I.…”

Section: Crystal Structurementioning

confidence: 99%

Electronic properties of layered multicomponent wide-band-gap oxides: A combinatorial approach

Murat

Medvedeva

2012

Phys. Rev. B

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The structural, electronic, and optical properties of twelve multicomponent oxides with layered structure, RAMO4, where R 3+ =In or Sc; A 3+ =Al or Ga; and M 2+ =Ca, Cd, Mg, or Zn, are investigated using first-principles density functional approach. The compositional complexity of RAMO4 leads to a wide range of band gap values varying from 2.45 eV for InGaCdO4 to 6.29 eV for ScAlMgO4 as obtained from our self-consistent screened-exchange local density approximation calculations. Strikingly, despite the different band gaps in the oxide constituents, namely, 2-4 eV in CdO, In2O3, or ZnO; 5-6 eV for Ga2O3 or Sc2O3; and 7-9 eV in CaO, MgO, or Al2O3, the bottom of the conduction band in the multicomponent oxides is formed from the s-states of all cations and their neighboring oxygen p-states. We show that the hybrid nature of the conduction band in multicomponent oxides originates from the unusual five-fold atomic coordination of A 3+ and M 2+ cations which enables the interaction between the spatially-spread s-orbitals of adjacent cations via shared oxygen atoms. The effect of the local atomic coordination on the band gap, the electron effective mass, the orbital composition of the conduction band, and the expected (an)isotropic character of the electron transport in layered RAMO4 is thoroughly discussed.

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“…1(a) [33][34][35][36]. In these compounds, In 3+ ions have octahedral coordination with the oxygen atoms and reside in 3(a) position (Yb), whereas both A 3+ (Al or Ga) and M 2+ (Ca or Zn) ions reside in 6(c) position (Fe), Fig.…”

Section: Approachmentioning

confidence: 99%

“…This also means that there is no available elemental chemical potentials which would allow the formation of the corresponding multicomponent oxides. Since the latter are stable above 1000 • C [33,34,36], the entropy term T ∆S must be taken into consideration. Similar arguments were reported for In 2 O 3 (ZnO) k compounds [43].…”

Section: Approachmentioning

confidence: 99%

Composition-dependent oxygen vacancy formation in multicomponent wide-band-gap oxides

Murat

Medvedeva

2012

Phys. Rev. B

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The formation and distribution of oxygen vacancy in layered multicomponent InAM O4 oxides with A 3+ =Al or Ga, and M 2+ =Ca or Zn, and in the corresponding binary oxide constituents is investigated using first-principles density functional calculations. Comparing the calculated formation energies of the oxygen defect at six different site locations within the structurally and chemically distinct layers of InAM O4 oxides, we find that the vacancy distribution is significantly affected not only by the strength of the metal-oxygen bonding, but also by the cation's ability to adjust to anisotropic oxygen environment created by the vacancy. In particular, the tendency of Zn, Ga, and Al atoms to form stable structures with low oxygen coordination, results in nearly identical vacancy concentrations in the InO1.5 and GaZnO2.5 layers in InGaZnO4, and only an order of magnitude lower concentration in the AlZnO2.5 layer as compared to the one in the InO1.5 layer in InAlZnO4. The presence of two light metal constituents in the InAlCaO4 along with Ca failure to form a stable fourfold coordination as revealed by its negligible relaxation near the defect, leads to a strong preference of the oxygen vacancy to be in the InO1.5 layer. Based on the results obtained, we derive general rules on the role of chemical composition, local coordination, and atomic relaxation in the defect formation and propose an alternative light-metal oxide as a promising constituent of multicomponent functional materials with tunable properties.

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Spinel, YbFe2O4, and Yb2Fe3O7 types of structures for compounds in the In2O3 and Sc2O3A2O3BO systems [A: Fe, Ga, or Al; B: Mg, Mn, Fe, Ni, Cu, or Zn] at temperatures over 1000°C

Cited by 220 publications

References 5 publications

Sc2Ga2CuO7: A possible quantum spin liquid near the percolation threshold

Sc2Ga2CuO7: A possible quantum spin liquid near the percolation threshold

Electronic properties of layered multicomponent wide-band-gap oxides: A combinatorial approach

Composition-dependent oxygen vacancy formation in multicomponent wide-band-gap oxides

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