Influence of metal content on size, dispersion, and magnetic properties of iron-cobalt alloy nanoparticles embedded in silica matrix

Guido Ennas*, Andrea Falqui, Sergio Marras, Claudio Sangregorio, Giaime Marongiu

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

48 Scopus citations

Abstract

(FexCo1-x)y(SiO2)1-y nanocomposites were prepared by a sol-gel method, using tetraethoxysilane and metal acetates as precursors. Two sets of xerogel samples were prepared: in the first set x was kept equal to 0.5 and four y values were selected in the range 0.02-0.2; in the second set y was kept equal to 0.1 and three samples with x equal to 0.45, 0.50, and 0.70 were prepared. The samples were characterized by X-ray diffraction, TEM, and HREM to verify the formation of the FeCo alloy nanocrystals and to investigate their structure, morphology, and composition. All samples contain spherical FeCo alloy nanoparticles uniformly dispersed in the silica matrix with average size increasing with metal content. Magnetic measurements carried out on selected samples show a superparamagnetic behavior, with blocking temperature which depends on metal load, as a consequence of particle distance variation.

Original languageEnglish (US)
Pages (from-to)5659-5663
Number of pages5
JournalChemistry of Materials
Volume16
Issue number26
DOIs
StatePublished - Dec 28 2004
Externally publishedYes

ASJC Scopus subject areas

  • Materials Chemistry
  • Materials Science(all)

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