From n = 1 to n = 2 of the Ruddlesden−Popper Phases via Ca-doping and induced effects on electrical and optical properties of La 2-x Ca x CuO 4-δ

Midouni, Adnene; Houchati, Mohamed Ikbal; Chniba-Boudjada, N.; Hamzaoui, Ahmed Hichem

doi:10.1016/j.jpcs.2017.05.026

Cited by 11 publications

(3 citation statements)

References 55 publications

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“…Basically, the mentioned semi‐arcs and the slanting line are correlated to the electrode process, interfacial phases and non‐interfacial phases which have been broadly dealt with in the literature [38,39] . The temperature dependence of ionic conductivities for pure LCDC and LCDC@KHC nanocomposite is expressed by the Arrhenius's relation: [40,41]

true σ (T) = \frac{A}{T} \exp (\frac{- E_{a}}{k_{normalB} T})

…”

Section: Resultsmentioning

confidence: 99%

New Approach to Improve Ionic Conductivity at Low Temperature by the Decomposition of KHCO₃ in the Nanocomposite Electrolyte @

et al. 2020

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The current work principally treats the significant aspects of solid electrolytes based on cerium oxide in the absence and presence of potassium bicarbonate. The classic oxide electrolyteCe0.7La0.15Ca0.15normalO2-δ (LCDC) and the bicarbonate nanocomposite electrolyteCe0.7La0.15Ca0.15normalO2-δ @KHCO3 (LCDC@KHC) are synthesized separately via self‐combustion and co‐precipitation techniques. Structural, thermal, electro‐morphological and electrochemical properties of pure LCDC and nanocomposite material LCDC@KHC are carefully examined. In particular, the influence of the heavily coupling amongst LCDC oxide and KHCO3 bicarbonate on the microstructures and ionic conductivities of KHCO3‐coated nanocrystalline LCDC is studied by TG/DTA, Raman, FEGSEM and AC impedance spectroscopy. Thermal analyses show that the LCDC@KHC nacomposite is stable at a temperature below 122 °C. Beyond this temperature, the LCDC@KHCO3 nanocomposite is transformed into a LCDC@normalKnormalHnormalCnormalO3/normalK2normalCnormalO3 nanocomposite. XRD data confirms that the LCDC phase and the various nanocomposite materials LCDC@KHC, sintering at different temperatures, adopt the fluorite structure. Lattice parameters and bond lengths are determined by Rietveld refinement. The ionic conductivity of bicarbonate nanocomposite electrolyte LCDC@KHC is 100 to 1000 times higher than that of the novel classic electrolyte LCDC. The remarkable enhancement of conductivity as a function of temperature rise is correlated to the presence of potassium in two forms: bicarbonate and carbonate in the LCDC@normalKnormalHnormalCnormalO3/normalK2normalCnormalO3 nanocomposite electrolyte.

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true σ (T) = \frac{A}{T} \exp (\frac{- E_{a}}{k_{normalB} T})

…”

Section: Resultsmentioning

confidence: 99%

New Approach to Improve Ionic Conductivity at Low Temperature by the Decomposition of KHCO₃ in the Nanocomposite Electrolyte @

et al. 2020

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“…Besides the BO octahedra distortion, they also identify the space group Cmce (SG 64) as the low (room) temperature phase. Previous experimental studies of Midouni et al 27 and Niwa et al 28 indicate the structural phase transition from the tetragonal to orthorhombic phase for La Cu CaO , Nd NiO and Pr NiO , respectively, depending on the A-cation and . Also, some papers based on the DFT calculations mention low symmetry structures for the perfect bulk crystal of (La Sr ) MO 29 (only the SG 64 is mentioned in Supporting Information 29 without a detailed discussion of the symmetry reduction mechanism) and Sr Fe O 30 (the Jahn-Teller effect is partially discussed for without SG specification).…”

Section: Introductionmentioning

confidence: 90%

Jahn–Teller distortion in Sr2FeO4: group-theoretical analysis and hybrid DFT calculations

Zvejnieks,

Mastrikov,

Gryaznov

2023

Sci Rep

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We present theoretical justification for distorted Ruddlesden–Popper (RP) phases of the first-order by using hybrid density functional theory (DFT) calculations and group-theoretical analysis. We, thus, demonstrate the existence of the Jahn–Teller effect around an Fe$$^{4\texttt {+}}$$ 4 + ion in Sr$$_{2}$$ 2 FeO$$_{4}$$ 4 . On the calculation side, we have established a combination of Wu–Cohen (WC) exchange and Perdew-Wang (PW) correlation in a three-parameter functional WC3PW, giving the most accurate description of Sr$$_{2}$$ 2 FeO$$_{4}$$ 4 from the comparison of three hybrid DFT functionals. Self-consistently obtained Hartree–Fock exact exchange of 0.16 demonstrates consistent results with the experimental literature data. Importantly, we explain conditions for co-existing proper and pseudo-Jahn–Teller effects from the crystalline orbitals, symmetry-mode analysis and irreps products. Moreover, phonon frequency calculations support and confirm the results of symmetry-mode analysis. In particular, the symmetry-mode analysis identifies a dominating irreducible representation of the Jahn-Teller mode (X2) and corresponding space group (SG) of ground state structure (SG Cmce model). Therefore, the usually suggested high-symmetry tetragonal crystal structure (SG I4/mmm model) is higher in energy by 121 meV/f.u. (equivalent to the Jahn-Teller stabilization energy) compared with the distorted low-symmetry structure (SG Cmce model). We also present diffraction patterns for the two crystal symmetries to discuss the differences. Therefore, our results shed light on the existence of low-symmetry RP phases and make possible direct comparisons with future experiments.

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“…Moreover, this layering arrangement influences their chemical and physical properties, rendering them suitable for various applications including their use as cathodes in solid oxide fuel cells, sensors, and catalysts for water splitting and the removal of organic pollutants. [1][2][3][4][5][6] In recent years, simple perovskites (ABO 3 , n = N) and layered perovskite oxides (n = 1, 2 and 3) have attracted considerable interest as semiconductor photocatalysts. This is attributed to their attractive characteristics including simple as well as elastic structures, high levels of stability and effective photo-oxidative capabilities, making them ideal for various applications.…”

Section: Introductionmentioning

confidence: 99%

Switching from antiferromagnetism to ferromagnetism in nanocrystalline La_1−xSr_1+xCoO₄ (x = 0.0, 0.2, 0.4 and 0.6) layered perovskite oxides: effects of mixed valence states of Co on their magnetic, optical and photocatalytic properties

Atri,

Qadir,

Sharma

et al. 2024

New J. Chem.

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From n = 1 to n = 2 of the Ruddlesden−Popper Phases via Ca-doping and induced effects on electrical and optical properties of La 2-x Ca x CuO 4-δ

Cited by 11 publications

References 55 publications

New Approach to Improve Ionic Conductivity at Low Temperature by the Decomposition of KHCO₃ in the Nanocomposite Electrolyte @

New Approach to Improve Ionic Conductivity at Low Temperature by the Decomposition of KHCO₃ in the Nanocomposite Electrolyte @

Jahn–Teller distortion in Sr2FeO4: group-theoretical analysis and hybrid DFT calculations

Switching from antiferromagnetism to ferromagnetism in nanocrystalline La_1−xSr_1+xCoO₄ (x = 0.0, 0.2, 0.4 and 0.6) layered perovskite oxides: effects of mixed valence states of Co on their magnetic, optical and photocatalytic properties

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From n = 1 to n = 2 of the Ruddlesden−Popper Phases via Ca-doping and induced effects on electrical and optical properties of La 2-x Ca x CuO 4-δ

Cited by 11 publications

References 55 publications

New Approach to Improve Ionic Conductivity at Low Temperature by the Decomposition of KHCO3 in the Nanocomposite Electrolyte @

New Approach to Improve Ionic Conductivity at Low Temperature by the Decomposition of KHCO3 in the Nanocomposite Electrolyte @

Jahn–Teller distortion in Sr2FeO4: group-theoretical analysis and hybrid DFT calculations

Switching from antiferromagnetism to ferromagnetism in nanocrystalline La1−xSr1+xCoO4 (x = 0.0, 0.2, 0.4 and 0.6) layered perovskite oxides: effects of mixed valence states of Co on their magnetic, optical and photocatalytic properties

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New Approach to Improve Ionic Conductivity at Low Temperature by the Decomposition of KHCO₃ in the Nanocomposite Electrolyte @

New Approach to Improve Ionic Conductivity at Low Temperature by the Decomposition of KHCO₃ in the Nanocomposite Electrolyte @

Switching from antiferromagnetism to ferromagnetism in nanocrystalline La_1−xSr_1+xCoO₄ (x = 0.0, 0.2, 0.4 and 0.6) layered perovskite oxides: effects of mixed valence states of Co on their magnetic, optical and photocatalytic properties