Electronic edition ISSN 1574-0579

The structure formation in concentrated suspensions of acicular magnets

V. A. Archekov , K. G. Kornev , S. V. Petrov , L. D. Eskin

Abstract
Collective variable method has been used to consider a possible formation of regions with nematic ordering in acicular magnet suspensions. Analysis has been conducted on the basis of Meier-Saupe approximation. The formation of three types of anisotropic structures has been shown and the concentration dependence of the orientation coefficient of particles on magnetic discs has been studied experimentally. In the case of acicular particles of γ−Fe₂O₃ this dependence exhibits maximum. The extremum of the orientation coefficient is reached at the concentration which is close to the critical one when phase transfer of isotropic solution-nematics II takes place. Figs 2, refs 13.