Comparison of surface effects in bare and titanium oxide coated CoFe2O4 nanoparticles

M. Zareef Kahn, K. Nadeem*, F. Zeb, Hur Abbas, Basit Ali, Ilse Letofsky-Papst

*Corresponding author for this work

Research output: Contribution to journalArticle

Abstract

Comparison of surface effects in bare and titanium oxide coated CoFe2O4 nanoparticles has been done with the help of magnetic measurements. The average crystallite size was 31 for bare CoFe2O4 nanoparticles. For titanium oxide coated nanoparticles, the CoFe2O4 and titanium oxide phases have crystallite size of 46 and 38 nm, respectively. TEM images confirmed the coating behavior of titanium oxide on CoFe2O4 nanoparticles. Both kinds of nanoparticles were in magnetically blocked state at room temperature as evident by ZFC/FC measurements. The effective anisotropy constant was calculated from simulated ZFC curve and found higher for bare CoFe2O4 nanoparticles due to large surface spin disorder and strong interparticle interactions. In modified Bloch's law fit for Ms vs. T data, the higher value of Bloch's constant for titanium oxide coated CoFe2O4 nanoparticles demonstrates the weak exchange coupling constant J. The Kneller's law fit for Hc vs. T data showed a lower value of constant α for titanium oxide coated CoFe2O4 nanoparticles which is due to the reduced surface magnetic and weak interparticle interactions. In summary, crystalline titanium oxide coating on CoFe2O4 nanoparticles showed reduction in surface spin disorder and weaken interparticle interactions.
Original languageEnglish
Article number106186
Number of pages6
JournalSolid State Sciences
Volume103
DOIs
Publication statusPublished - 2020

Keywords

  • Cobalt ferrite
  • Magnetic properties
  • Surface effects
  • Titanium oxide

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Chemistry(all)

Fields of Expertise

  • Advanced Materials Science

Treatment code (Nähere Zuordnung)

  • Basic - Fundamental (Grundlagenforschung)

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