Superparamagnetic behaviour of γ-Fe2O3 nanoparticles dispersed in a silica matrix

C. Cannas; G. Concas; D. Gatteschi; A. Falqui; A. Musinu; G. Piccaluga; C. Sangregorio; G. Spano

doi:10.1039/b008645m

Superparamagnetic behaviour of γ-Fe₂O₃ nanoparticles dispersed in a silica matrix

C. Cannas, G. Concas, D. Gatteschi, A. Falqui, A. Musinu, G. Piccaluga^*, C. Sangregorio, G. Spano

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

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Abstract

The structural and magnetic properties of two Fe₂O₃-SiO₂ nanocomposites, containing respectively 16.9 and 28.5 wt.% Fe₂O₃, were investigated. The samples were synthetized by a sol-gel method, using ethylene glycol as a solvent, and heating the gels gradually to 900°C. The procedure allowed us to obtain γ-Fe₂O₃ nanoparticles homogeneously dispersed in the amorphous silica matrix. The particles have a narrow size distribution and mean sizes from 3 to 6 nm depending on the iron oxide content. The magnetic properties of the samples were investigated by static and dynamic susceptibility measurements. All the samples showed superparamagnetic behaviour. The superparamagnetic relaxation was investigated also by Mössbauer spectroscopy. Hysteresis loops were measured at 2.5 K and both samples showed high values of coercive field. The role of magnetic interparticle interactions on the magnetic properties is discussed.

Original language	English (US)
Pages (from-to)	832-838
Number of pages	7
Journal	Physical Chemistry Chemical Physics
Volume	3
Issue number	5
DOIs	https://doi.org/10.1039/b008645m
State	Published - 2001
Externally published	Yes

ASJC Scopus subject areas

General Physics and Astronomy
Physical and Theoretical Chemistry

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title = "Superparamagnetic behaviour of γ-Fe2O3 nanoparticles dispersed in a silica matrix",

abstract = "The structural and magnetic properties of two Fe2O3-SiO2 nanocomposites, containing respectively 16.9 and 28.5 wt.% Fe2O3, were investigated. The samples were synthetized by a sol-gel method, using ethylene glycol as a solvent, and heating the gels gradually to 900°C. The procedure allowed us to obtain γ-Fe2O3 nanoparticles homogeneously dispersed in the amorphous silica matrix. The particles have a narrow size distribution and mean sizes from 3 to 6 nm depending on the iron oxide content. The magnetic properties of the samples were investigated by static and dynamic susceptibility measurements. All the samples showed superparamagnetic behaviour. The superparamagnetic relaxation was investigated also by M{\"o}ssbauer spectroscopy. Hysteresis loops were measured at 2.5 K and both samples showed high values of coercive field. The role of magnetic interparticle interactions on the magnetic properties is discussed.",

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doi = "10.1039/b008645m",

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TY - JOUR

T1 - Superparamagnetic behaviour of γ-Fe2O3 nanoparticles dispersed in a silica matrix

AU - Cannas, C.

AU - Concas, G.

AU - Gatteschi, D.

AU - Falqui, A.

AU - Musinu, A.

AU - Piccaluga, G.

AU - Sangregorio, C.

AU - Spano, G.

PY - 2001

Y1 - 2001

N2 - The structural and magnetic properties of two Fe2O3-SiO2 nanocomposites, containing respectively 16.9 and 28.5 wt.% Fe2O3, were investigated. The samples were synthetized by a sol-gel method, using ethylene glycol as a solvent, and heating the gels gradually to 900°C. The procedure allowed us to obtain γ-Fe2O3 nanoparticles homogeneously dispersed in the amorphous silica matrix. The particles have a narrow size distribution and mean sizes from 3 to 6 nm depending on the iron oxide content. The magnetic properties of the samples were investigated by static and dynamic susceptibility measurements. All the samples showed superparamagnetic behaviour. The superparamagnetic relaxation was investigated also by Mössbauer spectroscopy. Hysteresis loops were measured at 2.5 K and both samples showed high values of coercive field. The role of magnetic interparticle interactions on the magnetic properties is discussed.

AB - The structural and magnetic properties of two Fe2O3-SiO2 nanocomposites, containing respectively 16.9 and 28.5 wt.% Fe2O3, were investigated. The samples were synthetized by a sol-gel method, using ethylene glycol as a solvent, and heating the gels gradually to 900°C. The procedure allowed us to obtain γ-Fe2O3 nanoparticles homogeneously dispersed in the amorphous silica matrix. The particles have a narrow size distribution and mean sizes from 3 to 6 nm depending on the iron oxide content. The magnetic properties of the samples were investigated by static and dynamic susceptibility measurements. All the samples showed superparamagnetic behaviour. The superparamagnetic relaxation was investigated also by Mössbauer spectroscopy. Hysteresis loops were measured at 2.5 K and both samples showed high values of coercive field. The role of magnetic interparticle interactions on the magnetic properties is discussed.

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JO - Physical Chemistry Chemical Physics

JF - Physical Chemistry Chemical Physics

IS - 5

ER -

Superparamagnetic behaviour of γ-Fe₂O₃ nanoparticles dispersed in a silica matrix

Abstract

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