Percolation, relaxation halt, and retarded van der Waals interaction in dilute systems of iron nanoparticles

R. V. Chamberlin, J. Hemberger, A. Loidl, K. D. Humfeld, D. Farrell, S. Yamamuro, Y. Ijiri, S. A. Majetich

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24 Scopus citations

Abstract

We find three unanticipated features in the magnetic response of dilute systems of highly monodisperse Fe nanoparticles. Above a spin freezing temperature (Tf) the remanent magnetization relaxes smoothly to zero, but below Tf the relaxation halts abruptly at a nonzero value. The distribution of relaxation rates changes at a percolation temperature (Tp), consistent with chainlike structures above Tp and three-dimensional clusters below Tp. The blocking temperature (Tb) varies inversely proportional to particle diameter, opposite to the behavior of the Néel-Brown model for individual domains, but consistent with a type of Casimir-Polder interaction expected between dilute nanometer-scale particles.

Original languageEnglish (US)
Article number172403
Pages (from-to)1724031-1724034
Number of pages4
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume66
Issue number17
StatePublished - Nov 1 2002
Externally publishedYes

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ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

Cite this

Chamberlin, R. V., Hemberger, J., Loidl, A., Humfeld, K. D., Farrell, D., Yamamuro, S., Ijiri, Y., & Majetich, S. A. (2002). Percolation, relaxation halt, and retarded van der Waals interaction in dilute systems of iron nanoparticles. Physical Review B - Condensed Matter and Materials Physics, 66(17), 1724031-1724034. [172403].