Magnetic studies of SiO2 coated CoFe2O4 nanoparticles

Mukta V. Limaye, Shashi B. Singh, Raja Das, Pankaj Poddar, Majid K. Abyaneh, Sulabha K. Kulkarni

Research output: Contribution to journalArticlepeer-review

13 Citations (Scopus)

Abstract

Oleic acid capped CoFe2O4 nanoparticles which exhibit a high coercivity of ∼9.47 kOe at room temperature were coated with a robust coating of SiO2. We have used chemical synthesis method to obtain SiO2 coated CoFe2O4 nanoparticles with different weight percentages of CoFe2O4 in SiO2 (1.5, 3.1 and 4.8 wt.%). The morphological investigation of the coated nanoparticles by transmission electron microscopy shows that the particles are spherical with average size ∼160 nm. Infrared spectroscopy reveals that oleic acid capping on the surface of CoFe2O4 nanoparticles is retained after silica coating process. The complete coating of SiO2 on CoFe2O4 nanoparticles is confirmed by X-ray photoelectron spectroscopy as there is no signature of cobalt or iron ions on the surface. Magnetic measurements show that coercivity of SiO2 coated CoFe2O4 particles remains more or less unaffected as in CoFe2O4 nanoparticles at room temperature. In addition, the temperature dependent magnetic measurements show that at 5 K the CoFe2O4 and SiO2 coated 1.5 wt.% CoFe2O4 samples exhibit a very high value of coercivity (∼20 kOe) which is more than twice as compared to room temperature coercivity value (∼9.47 kOe). We conclude that silica coating in our study does not significantly affect the coercivity of CoFe2O4 nanoparticles.

Original languageEnglish
Pages (from-to)683-690
Number of pages8
JournalJournal of Magnetism and Magnetic Materials
Volume441
DOIs
Publication statusPublished - 01 Nov 2017
Externally publishedYes

Keywords

  • Chemical synthesis
  • Magnetic materials
  • Photoelectron spectroscopy

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