Cation ordering in NiFe2–xCrx O4‐spinels studied by Mössbauer spectroscopy in external fields

Winell, Sofia; Amcoff, Örjan; Ericsson, Tore

doi:10.1002/pssb.200743507

Cited by 12 publications

(3 citation statements)

References 17 publications

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“…The lattice constants in the NiAl 2-x Ga x O 4 system were found to increase linearly with increasing Ga concentration, in agreement with Vegard's law [19]. In the NiFe 2-x Cr x O 4 system, the lattice constant decreases slightly up to x = 1, and then increases slightly when x > 1, which is consistent with other studies [20].…”

Section: Synthesissupporting

confidence: 90%

Examination of the site preference of metals in NiAl2−GaO spinel-type oxides by X-ray absorption near-edge spectroscopy

Walker

Hayes

Grosvenor

2014

Journal of Electron Spectroscopy and Related Phenomena

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Materials adopting the spinel-type structure have received considerable attention owing to the compositional diversity and the large number of potential applications for these materials.Although many studies of ternary spinel-type oxides have been completed, few studies have investigated quaternary materials. The NiAl 2-x Ga x O 4 spinel-type system was investigated in this study by X-ray absorption near-edge spectroscopy (XANES) and powder X-ray diffraction to study how the metal-site preference changed depending on composition. The Al L 2,3 -edge XANES spectra showed that Al occupied the tetrahedral and octahedral sites when x in the chemical formula was low, and preferentially occupied the octahedral site as x increased. The Ga K-edge XANES spectra confirmed that Ga 3+ has a strong preference for residing in the tetrahedral site and that this ion only partially occupied the octahedral sites when the concentration of Ga 3+ in the system was sufficiently large. The Ni K-edge XANES spectra showed that Ni 2+ has a strong preference for residing in the octahedral site, and that more Ni 2+ was present in the tetrahedral site in NiAl 2 O 4 vs. NiGa 2 O 4 . Rietveld refinement of powder X-ray diffraction patterns from the ternary end members were in general agreement with these results.This study has demonstrated the utility of using XANES to investigate the site preference of Al and Ga through the examination of Al L 2,3 -and Ga K-edge spectra, respectively.

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Section: Synthesissupporting

confidence: 90%

Examination of the site preference of metals in NiAl2−GaO spinel-type oxides by X-ray absorption near-edge spectroscopy

Walker

Hayes

Grosvenor

2014

Journal of Electron Spectroscopy and Related Phenomena

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“…The bending of the Arrhenius plots for NiCr2O4 and NiFeCrO4 can be related to the resistance going from grain boundary to bulk domination (15), with NiFeCrO4 switching to a metallic-like conduction at T > 600°C. The overall decrease in activation energy follows the increase in degree of inversion of chromite spinels, Mg ≈ Zn < Ni < NiFe (32)(33)(34). The doped MnCr2O4 show all an increase in conductivity compared with the pure spinel.…”

Section: Materials Synthesis and Characterizationmentioning

confidence: 96%

Cr- and Ti-Based Spinels as Materials for Anodic Catalyst Support in PEM Electrolysis Cells: Assessing Corrosion Stability and Support Role in Catalyst Activity of Corrosion Stable Ceramics

Fenini¹,

Savaniu

Irvine

et al. 2018

ECS Trans.

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This work aims to determine the stability of Cr-and Ti-based spinels as catalyst supports for oxygen evolution reaction (OER) catalyst in PEM electrolyzers (PEMECs). Different compositions of MCr2O4 (M=Ni, NiFe, Zn, Mg) and MTi2O4 (Li, Mg, Mn) have been synthesized by solid state synthesis. Pure and doped Cr-based spinels exhibit low conductivities at the operating temperatures of PEMECs (<10 -4 S cm -1 ), while Ti-based spinels showed very high conductivities at room temperature (~10-100 S cm -1 ). Cr-spinels proved to be very stable to chemical corrosion testing, while Tispinels manifested substantial weight loss. The most promising materials (LiTi2O4, MnCr2O4, Cu-MnCr2O4) showed redox activity at potentials >1.5 V vs SHE. LiTi2O4 is completely oxidized upon cycling up to 2.0 V vs SHE. Mixtures of IrO2/oxide support deposited on glassy carbon were tested toward OER, which showed a 10% higher absolute current at 2.0 V vs SHE in the case of IrO2/Cu-MnCr2O4 compared with pure IrO2.

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“…Among spinel ferrites, nickel ferrites are of great interest due to their noteworthy properties such as large permeability at high frequency, high electrical resistivity, chemical stability, and cost-effectiveness [1][2][3][4]. NiFe 2 O 4 possess inverse spinel structure [5] in which Ni 2+ ions occupy half of the B sites, while half of the Fe 3+ ions rest on A sites, the other half on B sites.…”

Section: Introductionmentioning

confidence: 99%

Enhanced coercivity of NiFe_1–xDy_xCrO₄ ferrites synthesised by glycine-nitrate combustion method

Sharma

Verma

Choudhary

et al. 2019

Materials Science and Technology

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The present work was focused on the effect of small amounts of Dy doping on the structural and magnetic properties of Ni-Cr ferrite materials. All the ferrites possess cubic symmetry corresponding to the space group [Formula: see text] with small amounts of secondary phase DyFeO3. No regular trend in the lattice parameter a with Dy doping has been observed. Room temperature magnetisation results, obtained from Vibrating Sample Magnetometer measurements, showed a decrease in saturation magnetisation with Dy doping. Enhanced coercivity in undoped Ni-Cr ferrite is observed which was several orders of magnitude higher than that of the reported bulk material. Substitution of Dy in Ni-Cr ferrite further enhances coercivity thereby making the materials magnetically more hard.

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Cation ordering in NiFe_2–xCr_x O₄‐spinels studied by Mössbauer spectroscopy in external fields

Cited by 12 publications

References 17 publications

Examination of the site preference of metals in NiAl2−GaO spinel-type oxides by X-ray absorption near-edge spectroscopy

Examination of the site preference of metals in NiAl2−GaO spinel-type oxides by X-ray absorption near-edge spectroscopy

Cr- and Ti-Based Spinels as Materials for Anodic Catalyst Support in PEM Electrolysis Cells: Assessing Corrosion Stability and Support Role in Catalyst Activity of Corrosion Stable Ceramics

Enhanced coercivity of NiFe_1–xDy_xCrO₄ ferrites synthesised by glycine-nitrate combustion method

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Cation ordering in NiFe2–xCrx O4‐spinels studied by Mössbauer spectroscopy in external fields

Cited by 12 publications

References 17 publications

Examination of the site preference of metals in NiAl2−GaO spinel-type oxides by X-ray absorption near-edge spectroscopy

Examination of the site preference of metals in NiAl2−GaO spinel-type oxides by X-ray absorption near-edge spectroscopy

Cr- and Ti-Based Spinels as Materials for Anodic Catalyst Support in PEM Electrolysis Cells: Assessing Corrosion Stability and Support Role in Catalyst Activity of Corrosion Stable Ceramics

Enhanced coercivity of NiFe1–xDyxCrO4 ferrites synthesised by glycine-nitrate combustion method

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Cation ordering in NiFe_2–xCr_x O₄‐spinels studied by Mössbauer spectroscopy in external fields

Enhanced coercivity of NiFe_1–xDy_xCrO₄ ferrites synthesised by glycine-nitrate combustion method