Magnetic properties of iron-oxide small particles prepared on aluminum and MgO(100)

K. Fukumura, A. Nakanishi, T. Fujii, T. Kobayashi

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

Magnetic properties of small particles of iron oxide on an aluminum foil and a single crystal of MgO are studied by conversion electron Mössbauer spectroscopy (CEMS) at low temperature. The average thickness of the oxide layers is 3.0 nm on aluminum and 1.2 nm on MgO. The CEMS spectra are observed at 15-300 K with a gas-filled proportional counter which was developed in our laboratory. The hyperfine fields in the surface layer and in the core of the particles are separated. The diameter and magnetic anisotropy energy constant are 3.7 nm and 0.87 × 105 J/m3, and 3.5 nm and 2.4 × 105 J/m3, respectively, for small particles on aluminum and MgO. The large difference in the anisotropy constants of small particles on aluminum and MgO is attributed to the enhanced surface anisotropy, which may be caused by diffusion of magnesium ions into the lattice of iron oxide. The superparamagnetic blocking temperatures of these particles are 71 and 94 K, respectively.

Original languageEnglish
Pages (from-to)175-180
Number of pages6
JournalJournal of Magnetism and Magnetic Materials
Volume145
Issue number1-2
DOIs
Publication statusPublished - Mar 1 1995

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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