Coupling SMMs to a substrate: understanding molecule-surface interaction in molecular spintronic devices

Proposals of using molecules in technology in order to overcome the limits of current electronics have been many. Among the most studied is the use of single molecule magnets (SMMs) in spintronic devices. It is of utmost importance to understand the surface-molecule interaction and to be able to control this interaction so that the molecular properties are not obliterated by coupling to the surface. This is particularly challenging, and even more so when the surface is magnetic. We here demonstrate how a self-assembled monolayer of oleic acid can be used to dampen or buffer the magnetic coupling between an SMM and iron oxide. Our model is a simple iron oxide nanoparticle with an oleic acid layer onto which a 4f or 3d4f SMM has been grafted. Element specific XAS and XMCD data collected on the hybrid Co4Dy-NP system on Co, Dy and Fe edges show an extremely weak dipolar coupling between the SMM and the substrate. (author)