Structures and magnetic properties of oriented Fe/Au and Fe/Pt nanoparticles on a-Al2O3

B. Bian, Y. Hirotsu, K. Sato, T. Ohkubo, A. Makino

Research output: Contribution to journalArticle

38 Citations (Scopus)

Abstract

Granular thin films of oriented α-Fe nanoparticles on a-Al2O3 were fabricated by electron beam evaporation technique. The process took advantage of the overgrowth of α-Fe on Au or Pt 'seed' particles epitaxially grown on (100) NaCl substrates, which were later removed in distilled water. The crystallographic orientation between α-Fe and Au (Pt) nanocrystals was < 100>(Au(Pt))//<100>(Fe) with {010}(Au(Pt))//{011}(Fe). The magnetic coercivity of the oriented α-Fe particles was controllable by particle size and inter-particle distance. Annealing of the a-Al2O3/Fe/Pt films at temperatures higher than 500°C led to a formation of the ordered L10-FePt phase. Any one of the three <100> axes of the fcc parent phase acted as the tetragonal c-axis of the L10 superstructure. Magnetic coercivities of a-Al2O3/Fe/Pt films were found to be largely increased by heat treatment. The coercivity of the annealed a-Al2O3/Fe/Pt films reached as high as 3.5 kOe with a squareness of 0.74. It has been shown that magnetic property can be improved by controlling orientation and structure of the magnetic particles.

Original languageEnglish
Pages (from-to)753-759
Number of pages7
JournalJournal of Electron Microscopy
Volume48
Issue number6
DOIs
Publication statusPublished - 1999 Jan 1

Keywords

  • Fe/Au and Fe/Pt
  • Magnetic nanoparticles
  • Oriented nanoparticles

ASJC Scopus subject areas

  • Instrumentation

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