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Local structure at a ferrofluid surface: chain‐like aggregates revealed by non‐specular X‐ray reflection
Author(s) -
Doi S.,
Takahashi I.,
Tanaka N.
Publication year - 2003
Publication title -
journal of applied crystallography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.429
H-Index - 162
ISSN - 1600-5767
DOI - 10.1107/s0021889802023361
Subject(s) - ferrofluid , fractal dimension , specular reflection , anisotropy , fractal , materials science , reflection (computer programming) , chemical physics , optics , condensed matter physics , chemistry , physics , magnetic field , mathematical analysis , mathematics , quantum mechanics , computer science , programming language
The surface structure of a ferrofluid was investigated by means of non‐specular X‐ray reflection. Strong intensity that is impossible to explain by surface fluctuations due to capillary waves was observed. It can be related to lateral correlation within aggregates of super‐paramagnetic fine particles in the vicinity of the specimen surface. The fractal dimension of these surface‐induced aggregates and the surface‐tension coefficient of the ferrofluid were simultaneously determined. The fractal dimension was found to be around 1.1, indicating a chain‐like character of the aggregates that have few branches. Strong and anisotropic interaction among the particles, as well as irreversible aggregation kinetics must be the origin of such a high‐density and low‐fractal‐dimension system of dipolar 10 nm sized particles. The temperature variation of the fractal dimension indicated that the fractal aggregates stabilize themselves by losing their branches at increasing temperatures.