Structure and scattering in colloidal ferrofluids

The structure of a model colloidal ferrofluid, the dipolar hard-sphere fluid, at low temperature has been investigated using Monte Carlo simulations. Extensive particle association into chainlike and ringlike clusters is observed at low density. The structure factors have been calculated, and are analyzed with the aid of simple scaling arguments. We describe the progression of fluid structures from the low-density associated phase, to the high-density liquid phase. This paper may be of help in obtaining an experimental observation of a fluid-fluid transition in colloidal ferrofluids.