  Based on density-functional theory we analyze the full phase diagram, the
occurrence of long-ranged orientational order, and the structural properties of
dipolar fluids. As a model system we consider the Stockmayer fluid that
consists of spherical particles interacting via a Lennard-Jones potential plus
dipolar forces. For sufficiently strong dipole moments one finds a region where
a fluid phase with long-ranged orientational order is stable. For all sample
shapes with the exception of a long thin needle this phase exhibits a spatially
inhomogeneous magnetization which depends on the actual shape. We determine the
details of the magnetization structure in a cubic sample in the absence and in
the presence of an external magnetic field. One obtains a vortexlike structure
with an escape of the magnetization into the axis direction near the vortex
axis and two point defects where the absolute value of the magnetization is
strongly reduced. If the spherical cores of the particles are replaced by
elongated or oblate shapes a nematic phase without spontaneous magnetization is
also possible due to the anisotropic steric interactions. We study the
interplay of this nematic ordering with ferromagnetism in fluids of dipolar
hard ellipsoids. Orientational order arises locally in the isotropic fluid
phases near the liquid-gas interface of the Stockmayer fluid.
Density-functional theory allows us to determine density and orientational
order profiles as well as the surface tension of this interface.
