Reflectivity and off-specular neutron scattering from ferrofluid

Abstract

Near surface properties of ferrofluid (FF) are studied by means of the neutron reflectivity and off-specular scattering measured in zero magnetic field, and in a field applied within the surface plane, both perpendicular and parallel to the incoming beam direction. It is found that low magnetic fields substantially perturb the free FF surface which results in dramatic changes in specular reflection and the off-specular scattering. This phenomena may be attributed to the field-induced anisotropy in the particle density correlation function. The anisotropy is found to be much less pronounced at the interface between FF and the silicon wafer.