The structure of the adsorbed palmitic acid at the Fe oxide/oil interface has been investigated using polarised neutron reflectometry. The palmitic acid was found to be strongly adsorbed at the oxide/oil interface resulting in a monolayer of thickness 16±4 Å for 150, and 500 ppm palmitic acid concentrations (16±5 Å for the 1000 ppm solution). These layer thicknesses suggest tilt for the palmitic acid molecules with respect to the interface. The model also requires a second diffuse layer extending in the bulk oil. The thickness of this diffuse layer was 35±17 Å for the 150 ppm and 45±22 Å for 500 and 1000 ppm solutions. The composition profiles at the interface suggest a depletion of the oil in the vicinity of the interface as the concentration of palmitic acid increases.

Polarized neutron reflectometry is used to study the magnetic proximity effect in a superconductor/ferromagnet (SC/FM) system of composition Cu(32nm)/V(40nm)/Fe(1nm)/MgO. In contrast to previous studies, here a single SC/FM bilayer, is studied and multilayer artefacts are excluded. The necessary signal enhancement is achieved by waveguide resonance, i.e. preparing the V(40nm)/Fe(1nm) SC/FM bilayer sandwiched by the highly reflective MgO substrate and Cu top layer, respectively . A new magnetic state of the system was observed at temperatures below 0.7 T C . manifested in a systematic change in the height and width of the waveguide resonance peak. Upon increasing the temperature from 0.7 T C to T C , a gradual decay of this state is observed, accompanied by a 5% growth of the diffuse scattering. According to theoretical studies, such behavior is the result of the magnetic proximity effect. Due to the presence of the thin FM layer the superconducting electrons are polarized and, as a result, near the SC/FM interface an additional magnetic layer appears in the SC with thickness comparable to ξ, the coherence length of the superconductor.

Exchange bias (EB) is induced by oxygen implantation in three different ferromagnetic materials: polycrystalline Co, highly textured Co and polycrystalline Ni. These systems are compared in order to study the influence of the grain boundary density and the intrinsic ferromagnet/antiferromagnet coupling strength on the implantation-induced EB. Special emphasis is given to the role of the implantation profile in the EB properties. The implantation profile is thoroughly characterized and its correlation with the magnetic depth profile, i.e. the magnetization as a function of depth, for different magnetic states is studied. This is achieved by modelling the implanted system as a layered system. In the three systems, the magnetization reversal mechanism is studied. In this way the effect of the implantation process on the reversal mechanism is unraveled. Irrespective of the particular system, the magnetization reverses solely by domain wall nucleation and motion, as opposed to Co/CoO bilayer systems, where a change in the reversal mechanism is observed upon the first reversal.