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

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

Research output: Contribution to journal › Article › peer-review

Abstract

We find three unanticipated features in the magnetic response of dilute systems of highly monodisperse Fe nanoparticles. Above a spin freezing temperature (T_f) the remanent magnetization relaxes smoothly to zero, but below T_f the relaxation halts abruptly at a nonzero value. The distribution of relaxation rates changes at a percolation temperature (T_p), consistent with chainlike structures above T_p and three-dimensional clusters below T_p. The blocking temperature (T_b) 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 language	English (US)
Article number	172403
Pages (from-to)	1724031-1724034
Number of pages	4
Journal	Physical Review B - Condensed Matter and Materials Physics
Volume	66
Issue number	17
State	Published - Nov 1 2002
Externally published	Yes

ASJC Scopus subject areas

Electronic, Optical and Magnetic Materials
Condensed Matter Physics

Cite this

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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 N{\'e}el-Brown model for individual domains, but consistent with a type of Casimir-Polder interaction expected between dilute nanometer-scale particles.",

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AU - Chamberlin, R. V.

AU - Hemberger, J.

AU - Loidl, A.

AU - Humfeld, K. D.

AU - Farrell, D.

AU - Yamamuro, S.

AU - Ijiri, Y.

AU - Majetich, S. A.

PY - 2002/11/1

Y1 - 2002/11/1

N2 - 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.

AB - 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.

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

Abstract

ASJC Scopus subject areas

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