Grain size effect on the Néel temperature and magnetic properties of nanocrystalline NiFe2O4 spinel

C. N. Chinnasamy, A. Narayanasamy, N. Ponpandian, R. Justin Joseyphus, B. Jeyadevan, K. Tohji, K. Chattopadhyay

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110 Citations (Scopus)

Abstract

Nanocrystalline NiFe2O4 spinel ferrites with various grain sizes have been synthesized by ball milling the bulk NiFe2O4. The average grain sizes were estimated from the X-ray line broadening of the (3 1 1) reflection. The Néel temperatures of NiFe2O4 for various grain sizes were determined by magneto thermogravimetric method. The magnetic behaviour has been explained by combining the effects of changes in cation distribution on milling and finite size scaling. The shift in B-H loops has been correlated to the surface spin effects. The high coercivities observed here may be due to high anisotropies of the milled samples. The Hopkinson peak observed just below the Néel temperature has been explained by the mathematical formalism given by the Stoner Wohlfarth model.

Original languageEnglish
Pages (from-to)281-287
Number of pages7
JournalJournal of Magnetism and Magnetic Materials
Volume238
Issue number2-3
DOIs
Publication statusPublished - 2002 Jan

Keywords

  • Ferrimagnet
  • Fine particle
  • Hopkins effect
  • Néel temperature

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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