Magnetic Properties of Composite Hematite/Yttrium Oxide Colloidal Particles

Plaza, R.C.; Gómez-Lopera, S.A.; Delgado, A.V.

doi:10.1006/jcis.2001.7614

Cited by 11 publications

(11 citation statements)

References 23 publications

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“…The FT-IR spectra show good agreement with earlier published ones [12][13][14] and the XRD was compared and fitted to the diffractograms presented by Dimikrou et al [13] and Plaza et al [15] and JCPDS card No. 33-0664.…”

Section: Hematitementioning

confidence: 76%

Surface complex characteristics of synthetic maghemite and hematite in aqueous suspensions

Jarlbring

Gunneriusson

Hußmann

et al. 2005

Journal of Colloid and Interface Science

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Section: Hematitementioning

confidence: 76%

Surface complex characteristics of synthetic maghemite and hematite in aqueous suspensions

Jarlbring

Gunneriusson

Hußmann

et al. 2005

Journal of Colloid and Interface Science

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“…The feasibility and reproducibility of the synthesis route was first demonstrated by Aiken and Matijević (4), and other authors have subsequently investigated their lightscattering properties (10), surface characteristics (11)(12)(13), and magnetism (14).…”

Section: Introductionmentioning

confidence: 99%

Stability of Dispersions of Colloidal Hematite/Yttrium Oxide Core-Shell Particles

Plaza

Quirantes

Delgado

2002

Journal of Colloid and Interface Science

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The colloidal stability of suspensions of hematite/yttria core/shell particles is investigated in this work and compared with that of the pure hematite cores. The different electrical surface characteristics of yttrium and iron oxides, as well as the diameters of both types of spherical particles, dominate the overall process of particle aggregation. The aggregation kinetics of the suspensions was followed by measuring their optical absorbance as a function of time. By previously calculating the extinction cross section of particle doublets, it was demonstrated that for both core and core/shell particles the turbidity of the suspensions should increase on aggregation. Such an increase was in fact found in the systems in spite of the ever-present tendency of the particles to settle under gravity. The authors used the initial slope of the turbidity increment time plots as a measure of the ease of aggregation between particles. Thus, they found that the essential role played by pH on the charge generation on the two oxides and the shift of one pH unit between the isoelectric points of hematite and yttria manifest in two features: (i) the stability decreases on approaching the isoelectric point from either the acid or basic side and (ii) the maximum instability is found for hematite at pH 7 and for hematite/yttria at pH 8, that is, close to the isoelectric points of α-Fe 2 O 3 and Y 2 O 3 , respectively. The role of added electrolyte is simply to yield the suspensions of either type more unstable. Using the surface free energy of the particles, the authors could estimate their Hamaker constants in water. From these and their zeta potentials, the DLVO theory of stability was used to quantitatively explain their results. C 2002 Elsevier Science (USA)

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“…However, the particles size increases by increasing the milling time to 48 and 96 h. Fig. 2 [23]. From the XRD patterns, it is clear that as the milling time increases, the alloying treatment does not occur and the primary oxide powders are only milled.…”

Section: Resultsmentioning

confidence: 94%

“…Now the interpretation of the DTA curves is possible. The first exothermic peak is related to the recrystallization of a-Fe 2 O 3 and Y 2 O 3 , and crystallization of YFeO 3 at the interface of a-Fe 2 O 3 and Y 2 O 3 but because the diffusion of either yttrium or iron in the interface is very low [23], the reaction is limited. The second exothermic peak is composed of two peaks: one is related to the orthoferrite formation via the reaction Y 2 O 3 þ Fe 2 O 3 -2YFeO 3 and the second is related to the garnet formation via the reaction 3YFeO 3 þ Fe 2 O 3 -Y 3 Fe 5 O 12 [24].…”

Section: Resultsmentioning

confidence: 99%

Investigation of nanostructural, thermal and magnetic properties of yttrium iron garnet synthesized by mechanochemical method

Karami

Shokrollahi

Hashemi

2012

Journal of Magnetism and Magnetic Materials

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Magnetic Properties of Composite Hematite/Yttrium Oxide Colloidal Particles

Cited by 11 publications

References 23 publications

Surface complex characteristics of synthetic maghemite and hematite in aqueous suspensions

Surface complex characteristics of synthetic maghemite and hematite in aqueous suspensions

Stability of Dispersions of Colloidal Hematite/Yttrium Oxide Core-Shell Particles

Investigation of nanostructural, thermal and magnetic properties of yttrium iron garnet synthesized by mechanochemical method

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