Synchrotron X-ray powder diffraction studies on the order–disorder phase transition in lithium ferrites

Darul, J.; Nowicki, W.; Piszora, P.; Baehtz, Carsten; Wolska, E.

doi:10.1016/j.jallcom.2005.02.058

Cited by 15 publications

(3 citation statements)

References 10 publications

(11 reference statements)

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“…In region IV, Li 0.5 Fe 2.5 O 4 develops Li + /Fe 3+ ordering in octahedral sites and then crystalizes as ordered Li 0.5 Fe 2.5 O 4 in the P 4 3 32 space group. Darul et al also reported that synchrotron XRD measurements showed the crystallization of ordered Li 0.5 Fe 2.5 O 4 at 1033 K during cooling . Basically, γ-Fe 2 O 3 transforms to α-Fe 2 O 3 at 970 K under air flow, which was confirmed by the TG/DTA curves of γ-Fe 2 O 3 and the post-TG/DTA XRD measurement, as shown in Figure S15a,b, respectively.…”

Section: Resultsmentioning

confidence: 81%

Facile and Low-Temperature Synthesis of γ-Fe₂O₃ Nanoparticles with Thermally Stable Ferrimagnetism for Use in Magnetic Recording Tapes

Uyama

Mukai

Yamada

2020

ACS Appl. Nano Mater.

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Maghemite, γ-Fe 2 O 3 , has regained importance as a magnetic tape storage material for the big data era due to its low cost and long-term durability. However, the conventional synthesis of γ-Fe 2 O 3 , which involves dehydration, reduction, and oxidation processes, is complicated and requires improvement. We synthesized γ-Fe 2 O 3 directly via dehydration from the high-pressure phase of iron hydroxide, ϵ-FeOOH, using a low-temperature solution method. Bulk ϵ-FeOOH prepared from α-FeOOH at 8.2 GPa and 773 K transformed into γ-Fe 2 O 3 in a 2-phenoxyethanol and LiOH•H 2 O mixture at 498 K, which is the lowest temperature among similar dehydration reactions. 57 Fe Mossbauer, Raman, and Fourier transform infrared spectroscopy analyses revealed that the obtained γ-Fe 2 O 3 particles were covered with amorphous lithium phases, which stabilized their ferrimagnetism with a magnetization of 61.9 emu g −1 up to 1273 K, by converting to ferrimagnetic Li 0.5 Fe 2.5 O 4 . Furthermore, we reduced the size of γ-Fe 2 O 3 to an average of 0.5 μm and a minimum of approximately 100 nm by applying ϵ-FeOOH nanoparticles as a precursor, which were prepared under higher-pressure (10 GPa) and lower-temperature (673 K) conditions. Although synchrotron X-ray diffraction measurements found that the γ-Fe 2 O 3 nanoparticles were contaminated with ion-exchanged α-LiFeO 2 at 80 wt %, a facile and low-temperature method to synthesize γ-Fe 2 O 3 was established.

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Section: Resultsmentioning

confidence: 81%

Facile and Low-Temperature Synthesis of γ-Fe₂O₃ Nanoparticles with Thermally Stable Ferrimagnetism for Use in Magnetic Recording Tapes

Uyama

Mukai

Yamada

2020

ACS Appl. Nano Mater.

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“…Structural data for all samples obtained by the Rietveld refinements are reported in Tables I-III and [13]. It indicates that the ionic radii of A new report on the role of limited substitution with Mn 3+ , Cr 3+ and Al…”

Section: Resultsmentioning

confidence: 85%

Characterization of Structural Properties of LiM_xFe_5-xO₈(M=Al, Cr, Mn) Spinel Solid Solutions

Darul

2008

Acta Phys. Pol. A

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The structural properties of series spinel oxides with the general formula, LiM 0.5 Fe 4.5 O 8 (M = Mn, Cr, Al), are investigated. The effect of limited substitution of manganese, chromium and aluminum ions in the lithium ferrite samples on the order-disorder phase transition in the spinel crystal lattice at room temperature is presented. In these materials it is found that the ordered structures have not been isolated as single phases under the present experimental conditions and this fact will certainly influence the magnetic behavior of the compounds. The Rietveld refinements of the synchrotron X-ray diffraction data revealed that transition metal ions hinders the ordering process and Al 3+ ion was shown to be least effective in removing of order.

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“…A decrease in the lattice parameter values is observed at 900°C, for both materials. According to the literature, this behavior may be related to order-disorder phase transitions or to nor-mal-inverse spinel transitions, as a consequence of temperature increase [27][28][29].…”

Section: Resultsmentioning

confidence: 99%

Effect of the modifier ion on the properties of MgFe2O4 and ZnFe2O4 pigments

Xavier

Candeia

Bernardi³

et al. 2007

J Therm Anal Calorim

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Magnesium and zinc ferrites have been prepared by the polymeric precursor method. The organic material decomposition was studied by thermogravimetry (TG) and differential thermal analysis (DTA). The variation of crystalline phases and particle morphology with calcination temperature were investigated using X-ray diffraction (XRD) and scanning electronic microscopy (SEM), respectively. The colors of the ferrites were evaluated using colorimetry. Magnesium ferrite crystallizes above 800°C, presenting a yellow-orange color with a reflectance peak at the 600-650 nm range, while zinc ferrite crystallizes at 600°C, with a reflectance peak between 650-700 nm, corresponding to the red-brick color.

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Synchrotron X-ray powder diffraction studies on the order–disorder phase transition in lithium ferrites

Cited by 15 publications

References 10 publications

Facile and Low-Temperature Synthesis of γ-Fe₂O₃ Nanoparticles with Thermally Stable Ferrimagnetism for Use in Magnetic Recording Tapes

Facile and Low-Temperature Synthesis of γ-Fe₂O₃ Nanoparticles with Thermally Stable Ferrimagnetism for Use in Magnetic Recording Tapes

Characterization of Structural Properties of LiM_xFe_5-xO₈(M=Al, Cr, Mn) Spinel Solid Solutions

Effect of the modifier ion on the properties of MgFe2O4 and ZnFe2O4 pigments

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Synchrotron X-ray powder diffraction studies on the order–disorder phase transition in lithium ferrites

Cited by 15 publications

References 10 publications

Facile and Low-Temperature Synthesis of γ-Fe2O3 Nanoparticles with Thermally Stable Ferrimagnetism for Use in Magnetic Recording Tapes

Facile and Low-Temperature Synthesis of γ-Fe2O3 Nanoparticles with Thermally Stable Ferrimagnetism for Use in Magnetic Recording Tapes

Characterization of Structural Properties of LiMxFe5-xO8(M=Al, Cr, Mn) Spinel Solid Solutions

Effect of the modifier ion on the properties of MgFe2O4 and ZnFe2O4 pigments

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Product

Resources

About

Facile and Low-Temperature Synthesis of γ-Fe₂O₃ Nanoparticles with Thermally Stable Ferrimagnetism for Use in Magnetic Recording Tapes

Facile and Low-Temperature Synthesis of γ-Fe₂O₃ Nanoparticles with Thermally Stable Ferrimagnetism for Use in Magnetic Recording Tapes

Characterization of Structural Properties of LiM_xFe_5-xO₈(M=Al, Cr, Mn) Spinel Solid Solutions