Anisotropy-axis orientation effect on the magnetization of γ-Fe2O3 frozen ferrofluid
arXiv:1009.2610 · doi:10.1088/0022-3727/43/47/474001
Abstract
The effect of magnetic anisotropy-axis alignment on the superparamagnetic (SPM) and superspin glass (SSG) states in a frozen ferrofluid has been investigated. The ferrofluid studied here consists of maghemite nanoparticles (γ-Fe2O3, mean diameter = 8.6 nm) dispersed in glycerine at a volume fraction of ~15%. In the high temperature SPM state, the magnetization of aligned ferrofluid increased by a factor varying between 2 and 4 with respect to that in the randomly oriented state. The negative interaction energy obtained from the Curie-Weiss fit to the high temperature susceptibility in the SPM states as well as the SSG phase onset temperature determined from the linear magnetization curves were found to be rather insensitive to the anisotropy axis alignment. The low temperature aging behaviour, explored via "zero-field cooled magnetization" (ZFCM) relaxation measurements, however, show distinct difference in the aging dynamics in the anisotropy-axis aligned and randomly oriented SSG states.
to appear in Journal of Physics D: Applied Physics
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Cited by in corpus (4)
- Dynamic Correlation Length Growth in Superspin Glass: Bridging Experiments and Simulations
- Phase diagram for ensembles of random close packed Ising-like dipoles as a function of texturation
- Phase diagram of a three-dimensional dipolar Ising model with textured Ising axes
- Magnetic Relaxation in Two Dimensional Assembly of Dipolar Interacting Nanoparticles