ISSN:
1434-6036
Keywords:
PACS. 75.30.-m Intrinsic properties of magnetically ordered materials - 75.50.-y Studies of specific magnetic materials - 61.46.+w Clusters, nanoparticles, and nanocrystalline materials
Source:
Springer Online Journal Archives 1860-2000
Topics:
Physics
Notes:
Abstract: Four ferrofluids, distinct in size distribution and aggregate structure, were investigated. The relaxation time ,related to the temperature of susceptibility maximum, was fitted to a Vogel-Fulcher law. A mean ordering temperature, T0, was calculated using magnetic particle parameters derived from the structure. It is assumed that at T0 the particle moments of particle clusters correlate, leading to a spin glass-like transition. Hence, then dynamic slows down considerably, as indicated by a strong broadening of relaxation-time distribution. T0 roughly agrees with the energy of competing interaction between particle moments, as calculated from the structure of particle aggregates. Differences between particle arrangements clearly influence the dispersion and absorption, particularly within the cluster phase.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s100510050851
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