Size-induced structural phase transitions and hyperfine properties of microcrystalline Fe<sub>2</sub>O<sub>3</sub>

Ayyub, Pushan; Multani, M.S.; Barma, Mustansir; Palkar, V. R.; Vijayaraghavan, R.

doi:10.1088/0022-3719/21/11/014

Cited by 249 publications

(161 citation statements)

References 35 publications

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“…Further, microemulsion techniques have been criticized as an approach for synthesizing larger nanoparticles due to the formation of SPIO with poor crystallinity. 10 …”

Section: Microemulsionmentioning

confidence: 99%

Superparamagnetic Iron Oxide Nanoparticle Probes for Molecular Imaging

et al. 2006

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Abstract-The field of molecular imaging has recently seen rapid advances in the development of novel contrast agents and the implementation of insightful approaches to monitor biological processes non-invasively. In particular, superparamagnetic iron oxide nanoparticles (SPIO) have demonstrated their utility as an important tool for enhancing magnetic resonance contrast, allowing researchers to monitor not only anatomical changes, but physiological and molecular changes as well. Applications have ranged from detecting inflammatory diseases via the accumulation of non-targeted SPIO in infiltrating macrophages to the specific identification of cell surface markers expressed on tumors. In this article, we attempt to illustrate the broad utility of SPIO in molecular imaging, including some of the recent developments, such as the transformation of SPIO into an activatable probe termed the magnetic relaxation switch.

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“…Further, microemulsion techniques have been criticized as an approach for synthesizing larger nanoparticles due to the formation of SPIO with poor crystallinity. 10 …”

Section: Microemulsionmentioning

confidence: 99%

Superparamagnetic Iron Oxide Nanoparticle Probes for Molecular Imaging

et al. 2006

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“…Other nanoparticles synthesized in waterin-oil microemulsions include monodisperse silica particles [80-831, nano-size molybdenum sulfide particles [84], and magnetic particles such as magnetite [85,86] and maghemite [87].…”

Section: Particle Synthesis In Microemulsionsmentioning

confidence: 99%

Preparation of nanoparticles of silver halides, superconductors and magnetic materials using water-in-oil microemulsions as nano-reactors

Pillai

Kumar

Hou

et al. 1995

Advances in Colloid and Interface Science

249

121

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“…Within the last few decades the magnetic properties of nanocrystalline hematite have therefore attracted considerable attention. [2][3][4][5][6][7][8][9][10][11][12] Recently a sample of hematite nanoparticles with a size of about 16 nm, prepared by heating of Fe(NO 3 ) 3 •9H 2 O, was studied by magnetization measurements, x-ray and neutron diffraction, and Mössbauer spectroscopy. 12 The nanocrystalline hematite had a spontaneous magnetization of about 0.3-0.4 J T Ϫ1 kg Ϫ1 which is only slightly enhanced compared to the value for polycrystalline bulk WF hematite ͑0.3 J T Ϫ1 kg Ϫ1 ).…”

Section: Introductionmentioning

confidence: 99%

Magnetic dynamics of weakly and strongly interacting hematite nanoparticles

Hansen¹,

Koch

Mørup³

2000

Phys. Rev. B

207

241

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The magnetic dynamics of two differently treated samples of hematite nanoparticles from the same batch with a particle size of about 20 nm have been studied by Mössbauer spectroscopy. The dynamics of the first sample, in which the particles are coated and dispersed in water, is in accordance with the Néel expression for the superparamagnetic relaxation time of noninteracting particles. From a simultaneous analysis of a series of Mössbauer spectra, measured as a function of temperature, we obtain the median energy barrier K Bu V m /k ϭ570Ϯ100 K and the preexponential factor 0 ϭ1.3 Ϫ0.8 ϩ1.9 ϫ10 Ϫ10 s for a rotation of the sublattice magnetization directions in the rhombohedral ͑111͒ plane. The corresponding median superparamagnetic blocking temperature is about 150 K. The dynamics of the second, dry sample, in which the particles are uncoated and thus allowed to aggregate, is slowed down by interparticle interactions and a magnetically split spectrum is retained at room temperature. The temperature variation of the magnetic hyperfine field, corresponding to different quantiles in the hyperfine field distribution, can be consistently described by a mean field model for ''superferromagnetism'' in which the magnetic anisotropy is included. The coupling between the particles is due to exchange interactions and the interaction strength can be accounted for by just a few exchange bridges between surface atoms in neighboring crystallites.

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Size-induced structural phase transitions and hyperfine properties of microcrystalline Fe₂O₃

Cited by 249 publications

References 35 publications

Superparamagnetic Iron Oxide Nanoparticle Probes for Molecular Imaging

Superparamagnetic Iron Oxide Nanoparticle Probes for Molecular Imaging

Preparation of nanoparticles of silver halides, superconductors and magnetic materials using water-in-oil microemulsions as nano-reactors

Magnetic dynamics of weakly and strongly interacting hematite nanoparticles

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Size-induced structural phase transitions and hyperfine properties of microcrystalline Fe2O3

Cited by 249 publications

References 35 publications

Superparamagnetic Iron Oxide Nanoparticle Probes for Molecular Imaging

Superparamagnetic Iron Oxide Nanoparticle Probes for Molecular Imaging

Preparation of nanoparticles of silver halides, superconductors and magnetic materials using water-in-oil microemulsions as nano-reactors

Magnetic dynamics of weakly and strongly interacting hematite nanoparticles

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About

Size-induced structural phase transitions and hyperfine properties of microcrystalline Fe₂O₃