Cobalt doped γ-Fe 2 O 3 nanoparticles: Synthesis and magnetic properties

S. Chakrabarti, S. K. Mandal, S. Chaudhuri

Research output: Contribution to journalArticle

51 Citations (Scopus)

Abstract

We demonstrate here the wet chemical synthesis of cobalt doped γ-Fe 2 O 3 nanoparticles and the subsequent effect on magnetic properties with the variation in dopant concentration. It is observed that cobalt can be homogeneously doped into the γ-Fe 2 O 3 lattice up to 5 mol% without any appreciable change in the particle size (∼6 nm). Further increase in cobalt concentration (10 mol% here) resulted in an increase in particle size (∼9 nm) due to possible adsorption of a cobalt layer on the surface of γ-Fe 2 O 3 nanoparticles rather than complete doping in the iron oxide lattice. The ac susceptibility measurements revealed an increase in blocking temperature (T B ) with percentage variation in cobalt doping (2-10%), indicating substitution of Fe 3+ ions by Co 2+ ions in the γ-Fe 2 O 3 lattice. The dc magnetization measurements showed an increase in saturation magnetization only up to 5%, beyond which it significantly diminished. The reduction in saturation magnetization is attributed to the contribution from surface anisotropy in cobalt coated γ-Fe 2 O 3 nanoparticles.

Original languageEnglish
Pages (from-to)506-511
Number of pages6
JournalNanotechnology
Volume16
Issue number4
DOIs
Publication statusPublished - 1 Apr 2005

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Cobalt
Magnetic properties
Nanoparticles
Doping (additives)
Saturation magnetization
Particle size
Ions
Iron oxides
Magnetization
Anisotropy
Substitution reactions
Adsorption
Temperature

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Chakrabarti, S. ; Mandal, S. K. ; Chaudhuri, S. / Cobalt doped γ-Fe 2 O 3 nanoparticles : Synthesis and magnetic properties. In: Nanotechnology. 2005 ; Vol. 16, No. 4. pp. 506-511.
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Cobalt doped γ-Fe 2 O 3 nanoparticles : Synthesis and magnetic properties. / Chakrabarti, S.; Mandal, S. K.; Chaudhuri, S.

In: Nanotechnology, Vol. 16, No. 4, 01.04.2005, p. 506-511.

Research output: Contribution to journalArticle

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AB - We demonstrate here the wet chemical synthesis of cobalt doped γ-Fe 2 O 3 nanoparticles and the subsequent effect on magnetic properties with the variation in dopant concentration. It is observed that cobalt can be homogeneously doped into the γ-Fe 2 O 3 lattice up to 5 mol% without any appreciable change in the particle size (∼6 nm). Further increase in cobalt concentration (10 mol% here) resulted in an increase in particle size (∼9 nm) due to possible adsorption of a cobalt layer on the surface of γ-Fe 2 O 3 nanoparticles rather than complete doping in the iron oxide lattice. The ac susceptibility measurements revealed an increase in blocking temperature (T B ) with percentage variation in cobalt doping (2-10%), indicating substitution of Fe 3+ ions by Co 2+ ions in the γ-Fe 2 O 3 lattice. The dc magnetization measurements showed an increase in saturation magnetization only up to 5%, beyond which it significantly diminished. The reduction in saturation magnetization is attributed to the contribution from surface anisotropy in cobalt coated γ-Fe 2 O 3 nanoparticles.

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