Title

Crossover behavior in dynamics of frozen ferrofluids

Authors

Authors

X. D. Duan; J. L. Zhang;W. L. Luo

Comments

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Abbreviated Journal Title

J. Appl. Phys.

Keywords

MAGNETIC PARTICLE SYSTEM; GLASSES; LIQUIDS; Physics, Applied

Abstract

The imaginary part of susceptibility, chi", in frozen ferrofluids was measured as functions of temperature, frequency, and concentration of magnetic particles. In a very dilute region, where magnetic interaction is negligible, the relaxation time is mainly determined by Neel's relaxation in isolated particles and the frequency-dependent peak temperature in chi"(T), T-p, obeys the Arrhenius law. In the moderate concentration range, T-p has a Vogel-Fulcher (VF) relaxation with the measuring frequency. However, for concentration larger than a certain value, deviation from VF law occurs. Simulations show that the VF relation could be attributed to Ising spin-glass-like random and frustrated interaction between magnetic moments of particles. We suggest that particle configuration before freezing is critical to determine the distribution of pair exchange parameters. For high concentration, there are more ferromagnetic than antiferromagnetic bonds. The deviation from VF law at high concentration could be due to short range correlation among spins. (C) 2000 American Institute of Physics. [S0021- 8979(00)24908-6].

Journal Title

Journal of Applied Physics

Volume

87

Issue/Number

9

Publication Date

1-1-2000

Document Type

Article; Proceedings Paper

Language

English

First Page

6935

Last Page

6937

WOS Identifier

WOS:000086728800341

ISSN

0021-8979

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