Electric Double Layered Magnetic Fluids (EDL-MF) based on spinel ferrite nanostructures [(M1-x+2Fex+3)]A [(Fe2-x+3 Mx+2)]BO4-2

This paper presents a review of Electric Double Layered Magnetic Fluids (EDL-MF) based on spinel ferrite type [(M1-x+2Fex+3)]A [(Fe2-x+3 Mx+2)]BO4-2, with M(II) = Mn, Co, Ni, Cu and Zn. The chemical synthesis of the nanoparticles using hydrothermal techniques and their complete peptization in an aqueous medium results in a ultra stable magnetic colloid, EDL-MF. The characterization of the particles was performed using X-ray diffraction and electronic microscopy techniques. The resulted sols were investigated by magnetic, magneto-optical measurements and magnetic resonance techniques.

Authorship

F.A. Tourinho

Universidade de Brasília, Complex Fluid Group, Instituto de QuímicaUniversidade de BrasíliaUniversidade de Brasília, Complex Fluid Group, Instituto de Química

J. Depeyrot

Universidade de Brasília, Complex Fluid Group, Institute de Física, Brasília, DF, BrazilUniversidade de BrasíliaBrazilBrasília, DF, BrazilUniversidade de Brasília, Complex Fluid Group, Institute de Física, Brasília, DF, Brazil

G.J. da Silva

M.C.L. Lara

SCIMAGO INSTITUTIONS RANKINGS

Universidade de Brasília, Complex Fluid Group, Instituto de QuímicaUniversidade de BrasíliaUniversidade de Brasília, Complex Fluid Group, Instituto de Química

Figures | Tables

Figures (10)
Tables (2)

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Figure 1.
Size histogram of the Nickel EDL-MF sample deduced from electronic microscopy images (one thousand and a half particles). A best fit of this histogram by a log-normal distribution law gives a mean diameter d₀ = 3.4 nm and a standard deviation s = 0.15.

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Figure 2.
X-rays powder diffractogram of Copper, Zinc and Nickel ferrite nanoparticles. Characteristic lines [220], [311], [400], [511] and [440] of the spinel structure are indexed.

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Figure 6.
Log-log representation of Dn/F = f(H) for nickel EDL-MF's samples. The full line is a best fit using (5) which gives d₀ = 6.4 nm and s= 0.55.

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Figure 7.
Real and imaginary parts of the birefringence of the nickel EDL-MF sample as a function of frequency. The full lines correspond to the real and the imaginary parts of the Debye relaxation.

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Figure 8.
Normalized magnetic - resonance linewidth broadening is plotted as a function of 1000/T(K^-1). Particle concentration related to each samples is indicated in units of 10¹⁶ particles/cm³. The linewidth data were normalized with respect to the sample containing 6.3×10¹⁶ particles/cm³.

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Figure 9.
Normalized magnetic - resonance linewidth broadening is plotted as a function of 1000/T(K^-1) for the powder sample (solid triangles) obtained from the starting magnetic fluid sample. The continuous line through the solid triangles represents the best fit. The dashed curve represents the expected resonance -linewidth broadening for a magnetic -fluid sample containing 14.6×10¹⁶ particles/cm³.

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Figure 10.
The open circles are the experimental data obtained from an EPR spectrometer at X-Band, model ESP 300E made by Bruker. - The full lines are the fitting to theoretical models: for CuCl2 at the concentration of 1.0 M (molar) a lorentzian fits well, and the other points are fitted to equation 1 for a solution o CuCl₂ diluted at the ratio 1 part to 3, in the ferrofluid sample. The values of these concentration are listed near each curve.

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Table I:
Mean particle diameter estimated from the width at half maximum of the [311] diffraction peak for EDL-MF samples based on CuFe₂O₄, ZnFe₂O₄ and NiFe₂O₄ in powder form.

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Table II:
Adjusted values for R₀ and s as a functions of the Cu²⁺ dopant molar concentration.

Figure 1. Size histogram of the Nickel EDL-MF sample deduced from electronic microscopy images (one thousand and a half particles). A best fit of this histogram by a log-normal distribution law gives a mean diameter d₀ = 3.4 nm and a standard deviation s = 0.15.

Figure 2. X-rays powder diffractogram of Copper, Zinc and Nickel ferrite nanoparticles. Characteristic lines [220], [311], [400], [511] and [440] of the spinel structure are indexed.

Figure 6. Log-log representation of Dn/F = f(H) for nickel EDL-MF's samples. The full line is a best fit using (5) which gives d₀ = 6.4 nm and s= 0.55.

Figure 7. Real and imaginary parts of the birefringence of the nickel EDL-MF sample as a function of frequency. The full lines correspond to the real and the imaginary parts of the Debye relaxation.

Figure 8. Normalized magnetic - resonance linewidth broadening is plotted as a function of 1000/T(K^-1). Particle concentration related to each samples is indicated in units of 10¹⁶ particles/cm³. The linewidth data were normalized with respect to the sample containing 6.3×10¹⁶ particles/cm³.

Figure 9. Normalized magnetic - resonance linewidth broadening is plotted as a function of 1000/T(K^-1) for the powder sample (solid triangles) obtained from the starting magnetic fluid sample. The continuous line through the solid triangles represents the best fit. The dashed curve represents the expected resonance -linewidth broadening for a magnetic -fluid sample containing 14.6×10¹⁶ particles/cm³.

Figure 10. The open circles are the experimental data obtained from an EPR spectrometer at X-Band, model ESP 300E made by Bruker. - The full lines are the fitting to theoretical models: for CuCl2 at the concentration of 1.0 M (molar) a lorentzian fits well, and the other points are fitted to equation 1 for a solution o CuCl₂ diluted at the ratio 1 part to 3, in the ferrofluid sample. The values of these concentration are listed near each curve.

Table I: Mean particle diameter estimated from the width at half maximum of the [311] diffraction peak for EDL-MF samples based on CuFe₂O₄, ZnFe₂O₄ and NiFe₂O₄ in powder form.

Table II: Adjusted values for R₀ and s as a functions of the Cu²⁺ dopant molar concentration.

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Electric Double Layered Magnetic Fluids (EDL-MF) based on spinel ferrite nanostructures [(M1-x+2Fex+3)]A [(Fe2-x+3 Mx+2)]BO4-2

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