ZnFe2O4 nanoparticles for ferrofluids: A combined XANES and XRD study

Gomes, Juliano de Andrade; Azevedo, G. de M.; Depeyrot, J.; Mestnik-Filho, J.; Silva, G.J. da; Tourinho, F.A.; Perzynski, R.

doi:10.1016/j.jmmm.2010.11.006

Cited by 49 publications

(33 citation statements)

References 17 publications

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“…The NH 3 and NaOH sample spectra show a characteristic shape of Zn-ferrites that consist of three peaks between 9665 eV and 9675 eV. 26 Their relative intensity is typically considered as a fingerprint of the spinel inversion, namely the amount of Zn in octahedral sites. Most experimental and theoretical work reports that the relative intensity of the middle peak rises with inversion, 27 while the first and third peaks are usually identical in intensity.…”

Section: Resultsmentioning

confidence: 99%

Pushing up the magnetisation values for iron oxide nanoparticles via zinc doping: X-ray studies on the particle's sub-nano structure of different synthesis routes

Szczerba

Żukrowski

Przybylski

et al. 2016

Phys. Chem. Chem. Phys.

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The maximum magnetisation (saturation magnetisation) obtainable for iron oxide nanoparticles can be increased by doping the nanocrystals with non-magnetic elements such as zinc. Herein, we closely study how only slightly different synthesis approaches towards such doped nanoparticles strongly influence the resulting sub-nano/atomic structure. We compare two co-precipitation approaches, where we only vary the base (NaOH versus NH), and a thermal decomposition route. These methods are the most commonly applied ones for synthesising doped iron oxide nanoparticles. The measurable magnetisation change upon zinc doping is about the same for all systems. However, the sub-nano structure, which we studied with Mössbauer and X-ray absorption near edge spectroscopy, differs tremendously. We found evidence that a much more complex picture has to be drawn regarding what happens upon Zn doping compared to what textbooks tell us about the mechanism. Our work demonstrates that it is crucial to study the obtained structures very precisely when "playing" with the atomic order in iron oxide nanocrystals.

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Section: Resultsmentioning

confidence: 99%

Pushing up the magnetisation values for iron oxide nanoparticles via zinc doping: X-ray studies on the particle's sub-nano structure of different synthesis routes

Szczerba

Żukrowski

Przybylski

et al. 2016

Phys. Chem. Chem. Phys.

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“…The pre-edge peak structure in K-edge XANES spectra of 3d transition metals is sensitive to the electronic and geometrical structure around the X-ray absorbing central atom (Yamamoto, 2008). Characterization of pre-edge features is useful for understanding materials in the fields of physics, chemistry and earth sciences (Boye et al, 2011;Gomes et al, 2011;Yogi et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

Temperature dependence of pre-edge features in TiK-edge XANES spectra forATiO₃(A= Ca and Sr),A₂TiO₄(A= Mg and Fe), TiO₂rutile and TiO₂anatase

Hiratoko

Yoshiasa

Nakatani

et al. 2013

J Synchrotron Radiat

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XANES (X-ray absorption near-edge structure) spectra of the Ti K-edges of ATiO3 (A = Ca and Sr), A2TiO4 (A = Mg and Fe), TiO2 rutile and TiO2 anatase were measured in the temperature range 20-900 K. Ti atoms for all samples were located in TiO6 octahedral sites. The absorption intensity invariant point (AIIP) was found to be between the pre-edge and post-edge. After the AIIP, amplitudes damped due to Debye-Waller factor effects with temperature. Amplitudes in the pre-edge region increased with temperature normally by thermal vibration. Use of the AIIP peak intensity as a standard point enables a quantitative comparison of the intensity of the pre-edge peaks in various titanium compounds over a wide temperature range.

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“…It can be noticed that the intensities of pre‐edge peaks of both metals K ‐edge and Fe K ‐edge for each metal ferrite powder are significantly distinct. This pre‐edge peak is a characteristic of tetrahedral symmetry arising from electric transition 1s → 3d quadrupole and 1s → 3d/4p (hybridization) dipole transition and relating to the quantity of transition metal cation in the tetrahedral sites . At metal K ‐edge, the intensity of pre‐edge peak is largest in MnFe 2 O 4 (Fig.…”

Section: Resultsmentioning

confidence: 94%

Synchrotron X-ray absorption spectroscopy and magnetic characteristics studies of metal ferrites (metal = Ni, Mn, Cu) synthesized by sol-gel auto-combustion method

Tangcharoen

Klysubun

Kongmark

et al. 2014

Phys. Status Solidi A

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In this work, the metal ferrites MFe 2 O 4 (M ¼ Ni, Mn, Cu) were synthesized from metal nitrate precursors by the sol-gel auto-combustion method using diethanolamine (DEA) as a potential fuel. The crystal structures of these ferrite powders were characterized by X-ray diffraction (XRD) technique confirming the complete formation of the single-phase cubic spinel crystal structure. The ferrimagnetism characteristic and the difference of the magnetic properties such as saturation magnetization (M s ), remanent magnetization (M r ), and coercivity (H c ) for each after-calcined ferrite sample were scrutinized through the ferrimagnetic hysteresis loop (M-H) obtained from the vibrating sample magnetometer (VSM) measurement. Moreover, the cation distribution and valence state of these ferrites were investigated by the Ni, Mn, Cu, and Fe K-edge X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) spectra using the synchrotron radiation light source. From the XAS results, the analyses of both XANES and EXAFS spectra show the existence of accurate oxidation state for transition metal ions and the interionic distance to the nearest neighbors in the spinel crystal structure. In particular, the curve-fitting analysis of Ni, Mn, Cu, and Fe K-edge EXAFS spectra indicates that the degree of inversion in these metal ferrites is entirely different and found to be 0.2 for MnFe 2 O 4 , 0.8 for CuFe 2 O 4 , and 1.0 for NiFe 2 O 4 , which are the important information for understanding their effects on relevant magnetic properties.

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ZnFe2O4 nanoparticles for ferrofluids: A combined XANES and XRD study

Cited by 49 publications

References 17 publications

Pushing up the magnetisation values for iron oxide nanoparticles via zinc doping: X-ray studies on the particle's sub-nano structure of different synthesis routes

Pushing up the magnetisation values for iron oxide nanoparticles via zinc doping: X-ray studies on the particle's sub-nano structure of different synthesis routes

Temperature dependence of pre-edge features in TiK-edge XANES spectra forATiO₃(A= Ca and Sr),A₂TiO₄(A= Mg and Fe), TiO₂rutile and TiO₂anatase

Synchrotron X-ray absorption spectroscopy and magnetic characteristics studies of metal ferrites (metal = Ni, Mn, Cu) synthesized by sol-gel auto-combustion method

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ZnFe2O4 nanoparticles for ferrofluids: A combined XANES and XRD study

Cited by 49 publications

References 17 publications

Pushing up the magnetisation values for iron oxide nanoparticles via zinc doping: X-ray studies on the particle's sub-nano structure of different synthesis routes

Pushing up the magnetisation values for iron oxide nanoparticles via zinc doping: X-ray studies on the particle's sub-nano structure of different synthesis routes

Temperature dependence of pre-edge features in TiK-edge XANES spectra forATiO3(A= Ca and Sr),A2TiO4(A= Mg and Fe), TiO2rutile and TiO2anatase

Synchrotron X-ray absorption spectroscopy and magnetic characteristics studies of metal ferrites (metal = Ni, Mn, Cu) synthesized by sol-gel auto-combustion method

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Temperature dependence of pre-edge features in TiK-edge XANES spectra forATiO₃(A= Ca and Sr),A₂TiO₄(A= Mg and Fe), TiO₂rutile and TiO₂anatase