Synthesis, morphology, and magnetic characterization of iron oxide nanowires and nanotubes

Lorenza Suber, Patrizia Imperatori, Giovanni Ausanio, Fabio Fabbri, Herbert Hofmeister

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Abstract

We have explored the synthesis of iron oxide particles, tubes, and fibrils within the pores of nanoporous polycarbonate and alumina membranes. The membranes contain uniformly distributed cylindrical pores with monodispersed diameters (varying between 20 and 200 nm) and thicknesses of 6 and 60 μm, respectively. By hydrolysis and polymerization of iron salts, particles of different sizes and phases were formed in the pores, building iron oxide particle nanowires. Alternatively, by the sol-gel technique, using as reagents metalloorganic compounds, fibrils and tubes of different iron oxide phases were prepared. Structural and morphological investigations performed using scanning electron microscopy and transmission electron microscopy revealed ordered iron oxide particle wires, tubes, and fibrils formed inside the membrane nanopores. Magnetic characterization was accomplished with a vibrating sample magnetometer. Below the blocking temperature (TB), the magnetic behavior of the nanowires was governed by dipolar interaction between nearest-neighbor nanoparticles inside the pore, whereas the energy barrier, and therefore the TBvalue, was mainly governed by dipolar interaction between magnetic moments over larger (interpore) distances. As expected, crystalline iron oxide nanotubes exhibited magnetic perpendicular anisotropy due to their magnetocrystalline and shape anisotropy. © 2005 American Chemical Society.
Original languageEnglish
Pages (from-to)7103 - 7109
Number of pages7
JournalJournal of Physical Chemistry B
Volume109
Issue number15
DOIs
Publication statusPublished - 21 Apr 2005
Externally publishedYes

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All Science Journal Classification (ASJC) codes

  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films
  • Materials Chemistry

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