Free rotation of magnetic nanoparticles in a solid matrix

E. Del Barco, J. Asenjo, X. X. Zhang, R. Pieczynski, A. Julià, J. Tejada*, R. F. Ziolo, D. Fiorani, A. M. Testa

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

47 Scopus citations


Magnetic data for a composite material consisting of nanocrystalline γ-Fe2O3 dispersed in an alginate methanol matrix indicate the presence of rotationally free magnetic particles. The decoupling of the particles from the matrix was achieved by subjecting the sample to a magnetic field applied in alternating directions. Before field treatment, a magnetic blocking process is observed at low temperature, which is characteristic of nanoscale magnetic materials in the presence of barriers for the magnetic moment of the particles. After the field treatment, no magnetic hysteresis is observed and the magnetization follows a Curie-Weiss law. This behavior can only be interpreted as due to magnetic moments that follow the external magnetic field without delay, implying, therefore, the existence of free particles.

Original languageEnglish (US)
Pages (from-to)1487-1490
Number of pages4
JournalChemistry of Materials
Issue number5
StatePublished - 2001
Externally publishedYes

ASJC Scopus subject areas

  • General Chemistry
  • General Chemical Engineering
  • Materials Chemistry


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