Hydrodynamics of nematic ferrofluids

Abstract:

We derive hydrodynamic equations for nematic ferrofluids (ferronematics) in the limit that the magnetic degree of freedom has relaxed to its equilibrium value. We concentrate on novel dynamic effects linear in the magnetic field. We show that flow alignment, heat conduction, diffusion, thermodiffusion, viscosity and director reorientation are all modified by the presence of an external field. In particular, the new effects describe reversible (irreversible) couplings, where the conventional effects are irreversible (reversible). We discuss, how these effects can be measured. In principle, this description is applicable to conventional nematics, too, although huge magnetic fields are expected to be necessary for detecting the new effects in this case.