Phase transitions in a ferrofluid at magnetic field induced microphase separation
Abstract
In the presence of a magnetic field applied perpendicular to a thin sample layer, a suspension of magnetic colloidal particles (ferrofluid) can form spatially modulated phases with a characteristic length determined by the competition between dipolar forces and short-range forces opposing density variations. We introduce models for thin-film ferrofluids in which magnetization and particle density are viewed as independent variables and in which the non-magnetic properties of the colloidal particles are described either by a lattice-gas entropy or by the Carnahan-Starling free energy. Our description is particularly well suited to the low-particle density regions studied in many experiments. Within mean-field theory, we find isotropic, hexagonal and stripe phases, separated in general by first-order phase boundaries.
Cite
@article{arxiv.cond-mat/0103429,
title = {Phase transitions in a ferrofluid at magnetic field induced microphase separation},
author = {D. Lacoste and T. C. Lubensky},
journal= {arXiv preprint arXiv:cond-mat/0103429},
year = {2009}
}
Comments
12 pages, RevTex, to appear in PRE