Barium hexaferrite ferrofluids – preparation and physical properties

Müller, Robert N.; Hiergeist, R.; Steinmetz, H.; Ayoub, N.Y.; Fujisaki, Masao; Schüppel, W.

doi:10.1016/s0304-8853(99)00016-5

Cited by 61 publications

(29 citation statements)

References 3 publications

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“…Peptization of the precipitated magnetic nanoparticle as ionic MF can be accomplished in low-pH as well as in high-pH values [45][46][47]. Fresh precipitate containing magnetic nanoparticle can be suspended in both non-polar solvents [48][49][50] and water-based media [51,52]. The as produced MF samples can be further used as an exceptional and highly-flexible platform to produce more complex nanosized magnetic material systems.…”

Section: The Materials Platform Provided By Magnetic Fluidsmentioning

confidence: 99%

Using Mössbauer spectroscopy as key technique in the investigation of nanosized magnetic particles for drug delivery

Morais

2008

Hyperfine Interact

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This paper describes how cobalt ferrite nanoparticles, suspended as ionic or biocompatible magnetic fluids, can be used as a platform to built complex nanosized magnetic materials, more specifically magnetic drug delivery systems. In particular, the paper is addressed to the discussion of the use of the Mössbauer spectroscopy as an extremely useful technique in supporting the investigation of key aspects related to the properties of the hosted magnetic nanosized particle. Example of the use of the Mössbauer spectroscopy in accessing information regarding the nanoparticle modification due to the empirical process which provides long term chemical stability is included in the paper.

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Section: The Materials Platform Provided By Magnetic Fluidsmentioning

confidence: 99%

Using Mössbauer spectroscopy as key technique in the investigation of nanosized magnetic particles for drug delivery

Morais

2008

Hyperfine Interact

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“…Magnetic fluids (MFs) are ultra-stable magnetic colloidal suspensions traditionally based on metal-oxide nanoparticles, as for instance, cubic [1] and hexagonal ferrites [2]. The iron-nitride magnetic fluid, on the other hand, has been introduced as a very promising material system for fundamental studies, for it combines high saturation magnetization with enhanced particle size polydispersity characteristics [3].…”

Section: Introductionmentioning

confidence: 99%

Magnetic investigation of iron-nitride-based magnetic fluid

et al. 2007

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Transmission electron microscopy (TEM), Mössbauer spectroscopy and magnetization measurements were used in the present study to investigate a non-aqueous ironnitride-based magnetic fluid (MF) sample containing about 2×10 16 particle/cm 3 . The TEM micrographs indicated spherical-shaped iron nitride nanoparticles with an average diameter of 12.3 nm and diameter dispersity of 0.14. The 77 K Mössbauer spectrum of the frozen MF sample indicated the presence of about 95% of the γ′-Fe 4 N phase, with a residual 5% of the ɛ-Fe 4 N phase. The temperature dependence of the magnetization was investigated under zero-field-cooled (ZFC) condition, in the temperature range of 4 to 165 K. The ZFCdata were curve-fitted using a new approach that takes into account the particle size distribution and the temperature dependence of the magnetocrystalline anisotropy, making the description of the experimental situation more realistic.

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“…Therefore, the superparamagnetic particles can be stabilized in the same way as nonmagnetic particles by using surfactants or increasing the surface charge with the pH value. [9] The polar surfactant can be absorbed onto particles' surfaces as a double layer when the suspension is made in polar media. The double-layer adsorption produces the electrostatic and steric repulsion and this repulsion is strong enough to stabilize the nanosized BaHF particles.…”

Section: Introductionmentioning

confidence: 99%

Surface analyses of barium hexaferrite particles for magnetic suspensions

Ovtar

Lisjak

Drofenik

2010

Surface & Interface Analysis

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The stabilization of a suspension made from barium hexaferrite (BaHF), hard magnetic particles was studied. The magnetic attraction between the particles of BaHF was reduced by the adsorption of the surfactant dodeclybenzene sulphonic acid (DBSa) onto the particles' surfaces. With the adsorption of the surfactant, the electrostatic and steric repulsions between the particles were enhanced and stable suspensions were prepared from three different powders of BaHF, with particles sizes 5-20, 10-130 and 40-300 nm. The stability of the suspensions was determined with zeta-potential, saturation-concentration measurements, TEM and FTIR spectroscopy. The zeta-potential was increased with the addition of surfactants and the saturation concentration was increased with the decreased particle size. A stable suspension of the largest particles with a very high saturation concentration was prepared only by avoiding the application of an external magnetic field during the preparation of the suspension. The adsorption of the surfactant was observed in the FTIR spectra as a shift of the band assignment to the Fe-O vibrations. The red shift of the band by 37 or 53 cm −1 appears with the adsorption of the DBSa, and a blue shift by 41 and 67 cm −1 was observed, where two surfactants, DBSa and acetic acid, were used. The band shift is only partly observed in the suspension of the largest particles due to the effect of the particles' sizes.

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Barium hexaferrite ferrofluids – preparation and physical properties

Cited by 61 publications

References 3 publications

Using Mössbauer spectroscopy as key technique in the investigation of nanosized magnetic particles for drug delivery

Using Mössbauer spectroscopy as key technique in the investigation of nanosized magnetic particles for drug delivery

Magnetic investigation of iron-nitride-based magnetic fluid

Surface analyses of barium hexaferrite particles for magnetic suspensions

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